Sometimes a library you are writing may have optional dependencies. E.g. “if apache http client is on the classpath, use it; otherwise – fallback to HttpURLConnection”. Why would you do that? For various reasons – when distributing a library and you may not want to force a big dependency footprint. On the other hand, a more advanced library may have performance benefits, so whoever needs these, may include it. Or you may want to allow easily pluggable implementations of some functionality – e.g. json serialization. Your library doesn’t care whether it’s Jackson, gson or native android json serialization – so you may provide implementations using all of these, and pick the one whose dependency is found. One way to achieve this is to explicitly specify/pass the library to use. When the user of your library/framework instantiates its main class, they can pass a booleanuseApacheClient=true, or an enum value JsonSerializer.JACKSON. That is not a bad option, as it forces the user to be aware of what dependency they are using (and is a de-facto dependency injection) Another option, used by spring among others, is to dynamically check is the dependency is available on the classpath. E.g. private static final boolean apacheClientPresent = isApacheHttpClientPresent(); private static boolean isApacheHttpClientPresent() { try { Class.forName("org.apache.http.client.HttpClient"); logger.info("Apache HTTP detected, using it for HTTP communication.); return true; } catch (ClassNotFoundException ex) { logger.info("Apache HTTP client not found, using HttpURLConnection."); return false; } } and then, whenever you need to make HTTP requests (where ApacheHttpClient and HttpURLConnectionClient are your custom implementations of your own HttpClient interface): HttpClient client = null; if (apacheClientPresent) { client = new ApacheHttpClient(); } else { client = new HttpURLConnectionClient(); } Note that it’s important to guard any code that may try to load classes from the dependency with the “isXPresent” boolean. Otherwise class loading exceptions may fly. E.g. in spring, they wrapped the Jackson dependencies in a MappingJackson2HttpMessageConverter if (jackson2Present) { this.messageConverters.add(new MappingJackson2HttpMessageConverter()); } That way, if Jackson is not present, the class is not instantiated and loading of Jackson classes is not attempted at all. Whether to prefer the automatic detection, or require explicit configuration of what underlying dependency to use, is a hard question. Because automatic detection may leave the user of your library unaware of the mechanism, and when they add a dependency for a different purpose, it may get picked by your library and behaviour may change (though it shouldn’t, tiny differences are always there). You should document that, of course, and even log messages (as above), but that may not be enough to avoid (un)pleasant surprises. So I can’t answer when to use which, and it should be decided case-by-case. This approach is applicable also to internal dependencies – your core module may look for a more specific module to be present in order to use it, and otherwise fallback to a default. E.g. you provide a default implementation of “elapsed time” using System.nano(), but when using Android you’d better rely on SystemClock for that – so you may want to detect whether your elapsed time android implementation is present. This looks like logical coupling, so in this scenario it’s maybe wiser to prefer to explicit approach, though. Overall, this is a nice technique to use optional dependencies, with a basic fallback; or one of many possible options without a fallback. And it’s good to know that you can do it, and have it in your “toolkit” of possible solutions to a problem. But you shouldn’t always use it over the explicit (dependency injection) option.

I have a few popular Oauth related posts on my blog. I have one pertaining to Oauth 1.0a, and I have one on the topic of Oauth 2.0 for use in mobile application development. However, I get a lot of requests to show how to accomplish an Oauth 2.0 connection in a web browser using only JavaScript and AngularJS. We’re going to better explore the process flow behind Oauth 2.0 to establish a secure connection with a provider of our choice. In this particular example we’ll be using Imgur because I personally think it is a great service. Before we begin, it is important to note that this tutorial will only work with providers that offer the implicit grant type. Oauth Implicit Grant Type via OauthLib: The implicit grant type is used to obtain access tokens (it does not support the issuance of refresh tokens) and is optimized for public clients known to operate a particular redirection URI. These clients are typically implemented in a browser using a scripting language such as JavaScript. Unlike the authorization code grant type, in which the client makes separate requests for authorization and for an access token, the client receives the access token as the result of the authorization request. You’ll know the provider supports the implicit grant type when they make use of response_type=token rather than response_type=code. So there are going to be a few requirements to accomplish this in AngularJS: We are going to be using the AngularJS UI-Router library We are going to have a stand-alone index.html page with multiple templates We are going to have a stand-alone oauth_callback.html page with no AngularJS involvement With that said, let’s go ahead and create our project to look like the following: project root templates login.html secure.html js app.js index.html oauth_callback.html The templates/login.html page is where we will initialize the Oauth flow. After reaching the oauth_callback.html page we will redirect to the templates/secure.html page which requires a successful sign in. Crack open your index.html file and add the following code: Now it is time to add some very basic HTML to our templates/login.html and templates/secure.html pages: Login Login with Imgur Secure Web Page Access Token: {{accessToken} Not much left to do now. Open your js/app.js file and add the following AngularJS code: var example = angular.module("example", ['ui.router']); example.config(function($stateProvider, $urlRouterProvider) { $stateProvider .state('login', { url: '/login', templateUrl: 'templates/login.html', controller: 'LoginController' }) .state('secure', { url: '/secure', templateUrl: 'templates/secure.html', controller: 'SecureController' }); $urlRouterProvider.otherwise('/login'); }); example.controller("LoginController", function($scope) { $scope.login = function() { window.location.href = "https://api.imgur.com/oauth2/authorize?client_id=" + "CLIENT_ID_HERE" + "&response_type=token" } }); example.controller("SecureController", function($scope) { $scope.accessToken = JSON.parse(window.localStorage.getItem("imgur")).oauth.access_token; }); We are first going to focus on the login method of the LoginController. Go ahead and add the following, pretty much taken exactly from the Imgur documentation: $scope.login = function() { window.location.href = "https://api.imgur.com/oauth2/authorize?client_id=" + "CLIENT_ID_HERE" + "&response_type=token" } This long URL has the following components: Parameter Description client_id The application id found in your Imgur developer dashboard response_type Authorization grant or implicit grant type. In our case token for implicit grant The values will typically change per provider, but the parameters will usually remain the same. Now let’s dive into the callback portion. After the Imgur login flow, it is going to send you to http://localhost/oauth_callback.html because that is what we’ve decided to enter into the Imgur dashboard. Crack open your oauth_callback.html file and add the following source code: Redirecting... If you’re familiar with the ng-cordova-oauth library that I made, you’ll know much of this code was copied from it. Basically what we’re doing is grabbing the current URL and parsing out all the token parameters that Imgur has provided us. We are then going to construct an object with these parameters and serialize them into local storage. Finally we are going to redirect into the secure area of our application. In order to test this we need to be running our site from a domain or localhost. We cannot test this via a file:// URL. If you’re on a Mac or Linux machine, the simplest thing to do is run sudo python -m SimpleHTTPServer 80 since both these platforms ship with Python. This will run your web application as localhost on port 80. A video version of this article can be seen below.

Before we dig into CAS (Compare And Swap) strategy and how is it used by atomic constructs like AtomicInteger, first consider this code: public class MyApp { private volatile int count = 0; public void upateVisitors() { ++count; //increment the visitors count } } This sample code is tracking the count of visitors to the application. Is there anything wrong with this code? What will happen if multiple threads try to update count? Actually the problem is simply marking count as volatile does not guarantee atomicity and ++count is not an atomic operations. To read more check this. Can we solve this problem if we mark the method itself synchronized as shown below: public class MyApp { private int count = 0; public synchronized void upateVisitors() { ++count; //increment the visitors count } } Will this work? If yes then what changes have we made actually? Does this code guarantee atomicity? Yes. Does this code guarantee visibility? Yes. Then what is the problem? It makes use of locking and that introduces lot of delay and overhead. Check this article. This is very expensive way of making things work. To overcome these problems atomic constructs were introduced. If we make use of an AtomicInteger to track the count it will work. public class MyApp { private AtomicInteger count = new AtomicInteger(0); public void upateVisitors() { count.incrementAndGet(); //increment the visitors count } } The classes that support atomic operations e.g. AtomicInteger, AtomicLong etc. makes use of CAS. CAS does not make use of locking rather it is very optimistic in nature. It follows these steps: Compare the value of the primitive to the value we have got in hand. If the values do not match it means some thread in between has changed the value. Else it will go ahead and swap the value with new value. Check the following code in AtomicLong class: public final long incrementAndGet() { for (;;) { long current = get(); long next = current + 1; if (compareAndSet(current, next)) return next; } } In JDK 8 the above code has been changed to a single intrinsic: public final long incrementAndGet() { return unsafe.getAndAddLong(this, valueOffset, 1L) + 1L; } What advantage this single intrinsic have? Actually this single line is JVM intrinsic which is translated by JIT into an optimized instruction sequence. In case of x86 architecture it is just a single CPU instruction LOCK XADD which might yield better performance than classic load CAS loop. Now think about the possibility when we have high contention and a number of threads want to update the same atomic variable. In that case there is a possibility that locking will outperform the atomic variables but in realistic contention levels atomic variables outperform lock. There is one more construct introduced in Java 8, LongAdder. As per the documentation: This class is usually preferable to AtomicLong when multiple threads update a common sum that is used for purposes such as collecting statistics, not for fine-grained synchronization control. Under low update contention, the two classes have similar characteristics. But under high contention, expected throughput of this class is significantly higher, at the expense of higher space consumption. So LongAdder is not always a replacement for AtomicLong. We need to consider the following aspects: When no contention is present AtomicLong performs better. LongAdder will allocate Cells (a final class declared in abstract class Striped64) to avoid contention which consumes memory. So in case we have a tight memory budget we should prefer AtomicLong. That's all folks. Hope you enjoyed it.

From a really long time, I wanted to write automation using the Tor Web Browser. My preferred automation framework is Selenium WebDriver. However, I found out that there isn’t a built-in integration between the two. I wasted almost half a day to discover how to combine them. Finally, I did it! You can find my discoveries below. What is Tor? Tor is free software and an open network that helps you defend against traffic analysis, a form of network surveillance that threatens personal freedom and privacy, confidential business activities and relationships, and state security. It was originally developed with the U.S. Navy in mind, for the primary purpose of protecting government communications. Today, it is used every day for a wide variety of purposes by normal people, the military, journalists, law enforcement officers, activists, and many others. As you can see Tor is a modified Firefox browser. You have all features of Firefox plus additional protection. Download it from here: https://www.torproject.org/ Integrate Tor and Selenium WebDriver You cannot start the Tor browser using IWebDriver interface because there isn’t an implementation for it. Once started the proxy generated by Tor can be accessed via “127.0.0.1 9051“. So the first step in the plan is to start a new instance of Тоr. Next we start a new FirefoxDriver configured with a new profile with the proxy settings generated by Tor. public IWebDriver Driver { get; set; } public Process TorProcess { get; set; } public WebDriverWait Wait { get; set; } [TestInitialize] public void SetupTest() { String torBinaryPath = @"C:\Users\aangelov\Desktop\Tor Browser\Browser\firefox.exe"; this.TorProcess = new Process(); this.TorProcess.StartInfo.FileName = torBinaryPath; this.TorProcess.StartInfo.Arguments = "-n"; this.TorProcess.StartInfo.WindowStyle = ProcessWindowStyle.Maximized; this.TorProcess.Start(); FirefoxProfile profile = new FirefoxProfile(); profile.SetPreference("network.proxy.type", 1); profile.SetPreference("network.proxy.socks", "127.0.0.1"); profile.SetPreference("network.proxy.socks_port", 9150); this.Driver = new FirefoxDriver(profile); this.Wait = new WebDriverWait(this.Driver, TimeSpan.FromSeconds(60)); } [TestCleanup] public void TeardownTest() { this.Driver.Quit(); this.TorProcess.Kill(); } By default, Tor is installed on your desktop. We start a new process of the browser which we kill in the test cleanup. The SetPreference method configures the Firefox profile to use the Tor’s proxy settings. You can validate the setup via the test below, just change the IP address with yours. The test will open http://whatismyipaddress.com/ and will verify that your FirefoxDriver is running with different IP. [TestMethod] public void Open_Tor_Browser() { this.Driver.Navigate().GoToUrl(@"http://whatismyipaddress.com/"); var expression = By.XPath("//*[@id='section_left']/div[2]"); this.Wait.Until(x => x.FindElement(expression)); var element = this.Driver.FindElement(expression); Assert.AreNotEqual("84.40.65.000", element.Text); } Change Tor Identity via Code As you know this special browser allows you to change your identity (IP address) via the magic Tor button. However, it’s possible to do it via telnet or C# code. Use the following guide for telnet: https://stem.torproject.org/faq.html % telnet localhost 9051 Trying 127.0.0.1... Connected to localhost. Escape character is '^]'. AUTHENTICATE 250 OK SIGNAL NEWNYM 250 OK In the following folder “C:\Users\{your_user}\Desktop\Tor Browser\Browser\TorBrowser\Data\Tor“, you are going to find torrc-defaults file (config file). If you want use password authentication, you need to generate a password hash. You can do it via the tor.exe –hash-password “your_password” command. Then open the torrc-defaults file and add the following line: hashedControlPassword 16:751C69A9B10D7F4260B04E0D07D7EBCB760EDCEBADD40CDAF40F1FB095 The string after hashedControlPassword is the hash generated for your password. Your file should be similar to this: # If non-zero, try to write to disk less frequently than we would otherwise. AvoidDiskWrites 1 # Where to send logging messages. Format is minSeverity[-maxSeverity] # (stderr|stdout|syslog|file FILENAME). Log notice stdout # Bind to this address to listen to connections from SOCKS-speaking # applications. SocksPort 9150 ControlPort 9151 hashedControlPassword 16:751C69A9B10D7F4260B04E0D07D7EBCB760EDCEBADD40CDAF40F1FB095 CookieAuthentication 0 ## fteproxy configuration ClientTransportPlugin fte exec TorBrowser\Tor\PluggableTransports\fteproxy --managed ## obfsproxy configuration ClientTransportPlugin obfs2,obfs3,scramblesuit exec TorBrowser\Tor\PluggableTransports\obfsproxy managed ## flash proxy configuration # # Change the second number here (9000) to the number of a port that can # receive connections from the Internet (the port for which you # configured port forwarding). ClientTransportPlugin flashproxy exec TorBrowser\Tor\PluggableTransports\flashproxy-client --register :0 :9000 ## meek configuration ClientTransportPlugin meek exec TorBrowser\Tor\PluggableTransports\terminateprocess-buffer TorBrowser\Tor\PluggableTransports\meek-client-torbrowser --exit-on-stdin-eof -- TorBrowser\Tor\PluggableTransports\meek-client Now you can use the following C# code to refresh the proxy settings. public void RefreshTorIdentity() { Socket server = null; try { IPEndPoint ip = new IPEndPoint(IPAddress.Parse("127.0.0.1"), 9151); server = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp); server.Connect(ip); server.Send(Encoding.ASCII.GetBytes("AUTHENTICATE \"johnsmith\"" + Environment.NewLine)); byte[] data = new byte[1024]; int receivedDataLength = server.Receive(data); string stringData = Encoding.ASCII.GetString(data, 0, receivedDataLength); server.Send(Encoding.ASCII.GetBytes("SIGNAL NEWNYM" + Environment.NewLine)); data = new byte[1024]; receivedDataLength = server.Receive(data); stringData = Encoding.ASCII.GetString(data, 0, receivedDataLength); if (!stringData.Contains("250")) { Console.WriteLine("Unable to signal new user to server."); server.Shutdown(SocketShutdown.Both); server.Close(); } } finally { server.Close(); } } You can find the full source code at the following address: https://github.com/angelovstanton/Projects/tree/master/Demos/TelerikAcademy_WebDriver

Basic Authentication is the simplest way to secure access to a resource.

Written by Dave Syer in the Spring blog In this article we continue our discussion of how to use Spring Security with Angular JS in a “single page application”. Here we show how to build an API Gateway to control the authentication and access to the backend resources using Spring Cloud. This is the fourth in a series of articles, and you can catch up on the basic building blocks of the application or build it from scratch by reading the first article, or you can just go straight to the source code in Github. In the last article we built a simple distributed application that used Spring Session to authenticate the backend resources. In this one we make the UI server into a reverse proxy to the backend resource server, fixing the issues with the last implementation (technical complexity introduced by custom token authentication), and giving us a lot of new options for controlling access from the browser client. Reminder: if you are working through this article with the sample application, be sure to clear your browser cache of cookies and HTTP Basic credentials. In Chrome the best way to do that for a single server is to open a new incognito window. Creating an API Gateway An API Gateway is a single point of entry (and control) for front end clients, which could be browser based (like the examples in this article) or mobile. The client only has to know the URL of one server, and the backend can be refactored at will with no change, which is a significant advantage. There are other advantages in terms of centralization and control: rate limiting, authentication, auditing and logging. And implementing a simple reverse proxy is really simple with Spring Cloud. If you were following along in the code, you will know that the application implementation at the end of the last article was a bit complicated, so it’s not a great place to iterate away from. There was, however, a halfway point which we could start from more easily, where the backend resource wasn’t yet secured with Spring Security. The source code for this is a separate project in Github so we are going to start from there. It has a UI server and a resource server and they are talking to each other. The resource server doesn’t have Spring Security yet so we can get the system working first and then add that layer. Declarative Reverse Proxy in One Line To turn it into an API Gateawy, the UI server needs one small tweak. Somewhere in the Spring configuration we need to add an @EnableZuulProxy annotation, e.g. in the main (only)application class: @SpringBootApplication @RestController @EnableZuulProxy public class UiApplication { ... } and in an external configuration file we need to map a local resource in the UI server to a remote one in the external configuration (“application.yml”): security: ... zuul: routes: resource: path: /resource/** url: http://localhost:9000 This says “map paths with the pattern /resource/** in this server to the same paths in the remote server at localhost:9000”. Simple and yet effective (OK so it’s 6 lines including the YAML, but you don’t always need that)! All we need to make this work is the right stuff on the classpath. For that purpose we have a few new lines in our Maven POM: org.springframework.cloud spring-cloud-starter-parent 1.0.0.BUILD-SNAPSHOT pom import org.springframework.cloud spring-cloud-starter-zuul ... Note the use of the “spring-cloud-starter-zuul” - it’s a starter POM just like the Spring Boot ones, but it governs the dependencies we need for this Zuul proxy. We are also using because we want to be able to depend on all the versions of transitive dependencies being correct. Consuming the Proxy in the Client With those changes in place our application still works, but we haven’t actually used the new proxy yet until we modify the client. Fortunately that’s trivial. We just need to go from this implementation of the “home” controller: angular.module('hello', [ 'ngRoute' ]) ... .controller('home', function($scope, $http) { $http.get('http://localhost:9000/').success(function(data) { $scope.greeting = data; }) }); to a local resource: angular.module('hello', [ 'ngRoute' ]) ... .controller('home', function($scope, $http) { $http.get('resource/').success(function(data) { $scope.greeting = data; }) }); Now when we fire up the servers everything is working and the requests are being proxied through the UI (API Gateway) to the resource server. Further Simplifications Even better: we don’t need the CORS filter any more in the resource server. We threw that one together pretty quickly anyway, and it should have been a red light that we had to do anything as technically focused by hand (especially where it concerns security). Fortunately it is now redundant, so we can just throw it away, and go back to sleeping at night! Securing the Resource Server You might remember in the intermediate state that we started from there is no security in place for the resource server. Aside: Lack of software security might not even be a problem if your network architecture mirrors the application architecture (you can just make the resource server physically inaccessible to anyone but the UI server). As a simple demonstration of that we can make the resource server only accessible on localhost. Just add this to application.properties in the resource server: server.address: 127.0.0.1 Wow, that was easy! Do that with a network address that’s only visible in your data center and you have a security solution that works for all resource servers and all user desktops. Suppose that we decide we do need security at the software level (quite likely for a number of reasons). That’s not going to be a problem, because all we need to do is add Spring Security as a dependency (in the resource server POM): org.springframework.boot spring-boot-starter-security That’s enough to get us a secure resource server, but it won’t get us a working application yet, for the same reason that it didn’t in Part III: there is no shared authentication state between the two servers. Sharing Authentication State We can use the same mechanism to share authentication (and CSRF) state as we did in the last, i.e. Spring Session. We add the dependency to both servers as before: org.springframework.session spring-session 1.0.0.RELEASE org.springframework.boot spring-boot-starter-redis but this time the configuration is much simpler because we can just add the same Filterdeclaration to both. First the UI server (adding @EnableRedisHttpSession): @SpringBootApplication @RestController @EnableZuulProxy @EnableRedisHttpSession public class UiApplication { ... } and then the resource server. There are two changes to make: one is adding@EnableRedisHttpSession and a HeaderHttpSessionStrategy bean to theResourceApplication: @SpringBootApplication @RestController @EnableRedisHttpSession class ResourceApplication { ... @Bean HeaderHttpSessionStrategy sessionStrategy() { new HeaderHttpSessionStrategy(); } } and the other is to explicitly ask for a non-stateless session creation policy inapplication.properties: security.sessions: NEVER As long as redis is still running in the background (use the fig.yml if you like to start it) then the system will work. Load the homepage for the UI at http://localhost:8080 and login and you will see the message from the backend rendered on the homepage. How Does it Work? What is going on behind the scenes now? First we can look at the HTTP requests in the UI server (and API Gateway): VERB PATH STATUS RESPONSE GET / 200 index.html GET /css/angular-bootstrap.css 200 Twitter bootstrap CSS GET /js/angular-bootstrap.js 200 Bootstrap and Angular JS GET /js/hello.js 200 Application logic GET /user 302 Redirect to login page GET /login 200 Whitelabel login page (ignored) GET /resource 302 Redirect to login page GET /login 200 Whitelabel login page (ignored) GET /login.html 200 Angular login form partial POST /login 302 Redirect to home page (ignored) GET /user 200 JSON authenticated user GET /resource 200 (Proxied) JSON greeting That’s identical to the sequence at the end of Part II except for the fact that the cookie names are slightly different (“SESSION” instead of “JSESSIONID”) because we are using Spring Session. But the architecture is different and that last request to “/resource” is special because it was proxied to the resource server. We can see the reverse proxy in action by looking at the “/trace” endpoint in the UI server (from Spring Boot Actuator, which we added with the Spring Cloud dependencies). Go tohttp://localhost:8080/trace in a browser and scroll to the end (if you don’t have one already get a JSON plugin for your browser to make it nice and readable). You will need to authenticate with HTTP Basic (browser popup), but the same credentials are valid as for your login form. At or near the end you should see a pair of requests something like this: { "timestamp": 1420558194546, "info": { "method": "GET", "path": "/", "query": "" "remote": true, "proxy": "resource", "headers": { "request": { "accept": "application/json, text/plain, */*", "x-xsrf-token": "542c7005-309c-4f50-8a1d-d6c74afe8260", "cookie": "SESSION=c18846b5-f805-4679-9820-cd13bd83be67; XSRF-TOKEN=542c7005-309c-4f50-8a1d-d6c74afe8260", "x-forwarded-prefix": "/resource", "x-forwarded-host": "localhost:8080" }, "response": { "Content-Type": "application/json;charset=UTF-8", "status": "200" } }, } }, { "timestamp": 1420558200232, "info": { "method": "GET", "path": "/resource/", "headers": { "request": { "host": "localhost:8080", "accept": "application/json, text/plain, */*", "x-xsrf-token": "542c7005-309c-4f50-8a1d-d6c74afe8260", "cookie": "SESSION=c18846b5-f805-4679-9820-cd13bd83be67; XSRF-TOKEN=542c7005-309c-4f50-8a1d-d6c74afe8260" }, "response": { "Content-Type": "application/json;charset=UTF-8", "status": "200" } } } }, The second entry there is the request from the client to the gateway on “/resource” and you can see the cookies (added by the browser) and the CSRF header (added by Angular as discussed inPart II). The first entry has remote: true and that means it’s tracing the call to the resource server. You can see it went out to a uri path “/” and you can see that (crucially) the cookies and CSRF headers have been sent too. Without Spring Session these headers would be meaningless to the resource server, but the way we have set it up it can now use those headers to re-constitute a session with authentication and CSRF token data. So the request is permitted and we are in business! Conclusion We covered quite a lot in this article but we got to a really nice place where there is a minimal amount of boilerplate code in our two servers, they are both nicely secure and the user experience isn’t compromised. That alone would be a reason to use the API Gateway pattern, but really we have only scratched the surface of what that might be used for (Netflix uses it for a lot of things). Read up on Spring Cloud to find out more on how to make it easy to add more features to the gateway. The next article in this series will extend the application architecture a bit by extracting the authentication responsibilities to a separate server (the Single Sign On pattern).

I am really interested in Computer Vision technology, so I started to dig deeper in this topic. This is how I found the code below for edge detection, a method belonging to object detection. If you are interested in implementing edge detection in C#, too, here you can find the code I tried. The code is from a prewritten C# camera library you can all access. To develop the edge detection function you only need to have a Visual C# WPF Application created in Visual Studio and the VOIPSDK.dll and NVA.dll files (from www.camera-sdk.com ) added to the references. Creating the user interface is the first step. It will help you to use edge detection by providing an easy-to-use interface. You will have two fields to display the original image and the processed image of the camera, you can set values for Canny Threshold and Canny Threshold Linking and you can set whether you want the edges of the detected elements to be white or colorized. You can find the code of the GUI under Form1.Designer.cs. Under Form1.cs there is the code for the edge detection function. You can see how to code is built up and what you should to create this function. There will be the different methods you have to call and all the configurations are described. Trust me, guys, this source code will help you a lot, it made my life easier. Good luck! // Form1.Designer.cs namespace EdgeDetection { partial class Form1 { /// /// Required designer variable. /// private System.ComponentModel.IContainer components = null; /// /// Clean up any resources being used. /// /// true if managed resources should be disposed; otherwise, false. protected override void Dispose(bool disposing) { if (disposing && (components != null)) { components.Dispose(); } base.Dispose(disposing); } #region Windows Form Designer generated code /// /// Required method for Designer support - do not modify /// the contents of this method with the code editor. /// private void InitializeComponent() { this.label1 = new System.Windows.Forms.Label(); this.label2 = new System.Windows.Forms.Label(); this.btn_Set = new System.Windows.Forms.Button(); this.tb_CannyThreshold = new System.Windows.Forms.TextBox(); this.groupBox1 = new System.Windows.Forms.GroupBox(); this.chk_Colorized = new System.Windows.Forms.CheckBox(); this.label3 = new System.Windows.Forms.Label(); this.tb_CannyThresholdLinking = new System.Windows.Forms.TextBox(); this.label4 = new System.Windows.Forms.Label(); this.groupBox1.SuspendLayout(); this.SuspendLayout(); // // label1 // this.label1.AutoSize = true; this.label1.Font = new System.Drawing.Font("Microsoft Sans Serif", 8.25F, System.Drawing.FontStyle.Bold, System.Drawing.GraphicsUnit.Point, ((byte)(238))); this.label1.Location = new System.Drawing.Point(30, 265); this.label1.Name = "label1"; this.label1.Size = new System.Drawing.Size(87, 13); this.label1.TabIndex = 0; this.label1.Text = "Original image"; // // label2 // this.label2.AutoSize = true; this.label2.Font = new System.Drawing.Font("Microsoft Sans Serif", 8.25F, System.Drawing.FontStyle.Bold, System.Drawing.GraphicsUnit.Point, ((byte)(238))); this.label2.Location = new System.Drawing.Point(370, 265); this.label2.Name = "label2"; this.label2.Size = new System.Drawing.Size(103, 13); this.label2.TabIndex = 1; this.label2.Text = "Processed image"; // // btn_Set // this.btn_Set.Location = new System.Drawing.Point(182, 188); this.btn_Set.Name = "btn_Set"; this.btn_Set.Size = new System.Drawing.Size(58, 23); this.btn_Set.TabIndex = 2; this.btn_Set.Text = "Set"; this.btn_Set.UseVisualStyleBackColor = true; this.btn_Set.Click += new System.EventHandler(this.btn_Set_Click); // // tb_CannyThreshold // this.tb_CannyThreshold.Location = new System.Drawing.Point(153, 31); this.tb_CannyThreshold.Name = "tb_CannyThreshold"; this.tb_CannyThreshold.Size = new System.Drawing.Size(87, 20); this.tb_CannyThreshold.TabIndex = 4; // // groupBox1 // this.groupBox1.Controls.Add(this.chk_Colorized); this.groupBox1.Controls.Add(this.label3); this.groupBox1.Controls.Add(this.tb_CannyThresholdLinking); this.groupBox1.Controls.Add(this.label4); this.groupBox1.Controls.Add(this.btn_Set); this.groupBox1.Controls.Add(this.tb_CannyThreshold); this.groupBox1.Location = new System.Drawing.Point(677, 12); this.groupBox1.Name = "groupBox1"; this.groupBox1.Size = new System.Drawing.Size(258, 230); this.groupBox1.TabIndex = 12; this.groupBox1.TabStop = false; this.groupBox1.Text = "Settings"; // // chk_Colorized // this.chk_Colorized.AutoSize = true; this.chk_Colorized.CheckAlign = System.Drawing.ContentAlignment.MiddleRight; this.chk_Colorized.Location = new System.Drawing.Point(98, 115); this.chk_Colorized.Name = "chk_Colorized"; this.chk_Colorized.Size = new System.Drawing.Size(69, 17); this.chk_Colorized.TabIndex = 15; this.chk_Colorized.Text = "Colorized"; this.chk_Colorized.UseVisualStyleBackColor = true; // // label3 // this.label3.AutoSize = true; this.label3.Location = new System.Drawing.Point(27, 76); this.label3.Name = "label3"; this.label3.Size = new System.Drawing.Size(121, 13); this.label3.TabIndex = 14; this.label3.Text = "CannyThresholdLinking:"; // // tb_CannyThresholdLinking // this.tb_CannyThresholdLinking.Location = new System.Drawing.Point(153, 73); this.tb_CannyThresholdLinking.Name = "tb_CannyThresholdLinking"; this.tb_CannyThresholdLinking.Size = new System.Drawing.Size(87, 20); this.tb_CannyThresholdLinking.TabIndex = 13; // // label4 // this.label4.AutoSize = true; this.label4.Location = new System.Drawing.Point(61, 34); this.label4.Name = "label4"; this.label4.Size = new System.Drawing.Size(87, 13); this.label4.TabIndex = 11; this.label4.Text = "CannyThreshold:"; // // MainForm // this.AutoScaleDimensions = new System.Drawing.SizeF(6F, 13F); this.AutoScaleMode = System.Windows.Forms.AutoScaleMode.Font; this.ClientSize = new System.Drawing.Size(947, 307); this.Controls.Add(this.groupBox1); this.Controls.Add(this.label2); this.Controls.Add(this.label1); this.FormBorderStyle = System.Windows.Forms.FormBorderStyle.FixedSingle; this.MaximizeBox = false; this.Name = "MainForm"; this.Text = "Edge Detection"; this.Load += new System.EventHandler(this.MainForm_Load); this.groupBox1.ResumeLayout(false); this.groupBox1.PerformLayout(); this.ResumeLayout(false); this.PerformLayout(); } #endregion private System.Windows.Forms.Label label1; private System.Windows.Forms.Label label2; private System.Windows.Forms.Button btn_Set; private System.Windows.Forms.TextBox tb_CannyThreshold; private System.Windows.Forms.GroupBox groupBox1; private System.Windows.Forms.Label label4; private System.Windows.Forms.Label label3; private System.Windows.Forms.TextBox tb_CannyThresholdLinking; private System.Windows.Forms.CheckBox chk_Colorized; } } // Form1.cs using System; using System.Drawing; using System.Windows.Forms; using Ozeki.Media.MediaHandlers; using Ozeki.Media.MediaHandlers.Video; using Ozeki.Media.MediaHandlers.Video.CV; using Ozeki.Media.MediaHandlers.Video.CV.Processer; using Ozeki.Media.Video.Controls; namespace EdgeDetection { public partial class Form1 : Form { WebCamera _webCamera; MediaConnector _connector; ImageProcesserHandler _imageProcesserHandler; IEdgeDetector _edgeDetector; FrameCapture _frameCapture; VideoViewerWF _originalView; VideoViewerWF _processedView; DrawingImageProvider _originalImageProvider; DrawingImageProvider _processedImageProvider; public Form1() { InitializeComponent(); } void MainForm_Load(object sender, EventArgs e) { Init(); SetVideoViewers(); InitDetectorFields(); ConnectWebcam(); Start(); } void Init() { _frameCapture = new FrameCapture(); _frameCapture.SetInterval(5); _webCamera = WebCamera.GetDefaultDevice(); _connector = new MediaConnector(); _originalImageProvider = new DrawingImageProvider(); _processedImageProvider = new DrawingImageProvider(); _edgeDetector = ImageProcesserFactory.CreateEdgeDetector(); _imageProcesserHandler = new ImageProcesserHandler(); _imageProcesserHandler.AddProcesser(_edgeDetector); } void SetVideoViewers() { _originalView = new VideoViewerWF { BackColor = Color.Black, Location = new Point(10, 20), Size = new Size(320, 240) }; _originalView.SetImageProvider(_originalImageProvider); Controls.Add(_originalView); _processedView = new VideoViewerWF { BackColor = Color.Black, Location = new Point(350, 20), Size = new Size(320, 240) }; _processedView.SetImageProvider(_processedImageProvider); Controls.Add(_processedView); } void InitDetectorFields() { InvokeGUIThread(() => { tb_CannyThreshold.Text = _edgeDetector.CannyThreshold.ToString(); tb_CannyThresholdLinking.Text = _edgeDetector.CannyThresholdLinking.ToString(); chk_Colorized.Checked = _edgeDetector.Colorized; }); } void ConnectWebcam() { _connector.Connect(_webCamera, _originalImageProvider); _connector.Connect(_webCamera, _frameCapture); _connector.Connect(_frameCapture, _imageProcesserHandler); _connector.Connect(_imageProcesserHandler, _processedImageProvider); } void Start() { _originalView.Start(); _processedView.Start(); _frameCapture.Start(); _webCamera.Start(); } void btn_Set_Click(object sender, EventArgs e) { InvokeGUIThread(() => { _edgeDetector.CannyThreshold = Double.Parse(tb_CannyThreshold.Text); _edgeDetector.CannyThresholdLinking = Double.Parse(tb_CannyThresholdLinking.Text); _edgeDetector.Colorized = chk_Colorized.Checked; }); } void InvokeGUIThread(Action action) { BeginInvoke(action); } } }

Of late, I have been looking into Microservice containers that are available out there to help speed up the development. Although, Microservice is a generic term however there is some consensus with respect to what it means. Hence, we may conveniently refer to the definition Microservice as an "architectural design pattern, in which complex applications are composed of small, independent processes communicating with each other using language-agnostic APIs. These services are small, highly decoupled and focus on doing a small task." There are several Microservice containers out there. However, in my experience I have found Dropwizard and Spring-boot to have had received more attention and they appear to be widely used compared to the rest. In my current role, I was asked create a comparison matrix between the two, so it's here below. Dropwizard Spring-Boot What is it? Dropwizard pulls together stable, mature libraries from the Java ecosystem into a simple, light-weight package that lets you focus on getting things done. [more...] Takes an opinionated view of building production-ready Spring applications. Spring Boot favours convention over configuration and is designed to get you up and running as quickly as possible. [more...] Overview? Dropwizard straddles the line between being a library and a framework. Provide performant, reliable implementations of everything a production-ready web application needs. [more...] Spring-boot takes an opinionated view of the Spring platform and third-party libraries so you can get started with minimum fuss. Most Spring Boot applications need very little Spring configuration. [more...] Out of the box features? Dropwizard has out-of-the-box support for sophisticated configuration, application metrics, logging, operational tools, and much more, allowing you and your team to ship a production-quality web service in the shortest time possible. [more...] Spring-boot provides a range of non-functional features that are common to large classes of projects (e.g. embedded servers, security, metrics, health checks, externalized configuration). [more...] Libraries Core: Jetty, Jersey, Jackson and Matrics Others: Guava, Liquibase and Joda Time. Spring, JUnit, Logback, Guava. There are several starter POM files covering various use cases, which can be included in the POM to get started. Dependency Injection? No built in Dependency Injection. Requires a 3rd party dependency injection framework such as Guice, CDI or Dagger. [Ref...] Built in Dependency Injection provided by Spring Dependency Injection container. [Ref...] Types of Services i.e. REST, SOAP Has some support for other types of services but primarily is designed for performant HTTP/REST LAYER. If ever need to integrate SOAP, there is a dropwizard bundle for building SOAP web services using JAX-WS API is provided here but it’s not official drop-wizard sub project. [more...] As well as supporting REST Spring-boot has support for other types of services such as JMS, Advanced Message Queuing Protocol, SOAP based Web Services to name a few. [more...] Deployment? How it creates the Executable Jar? Uses Shading to build executable fat jars, where a shaded jar spackages all classes, from all jars, into a single 'uber jar'. [Ref...] Spring-boot adopts a different approach and avoids shaded jars, as it becomes hard to see which libraries you are actually using in your application. It can also be problematic if the same filename is used in Shaded jars. Instead it uses “Nested Jar” approach where all classes from all jars do not need to be included into a single “uber jar” instead all dependent jars should be in the “lib” folder, spring loader loads them appropriately. [Ref...] Contract First Web Services? No built in support. Would have to refer to 3rd party library (CXF or any other JAX-WS implementation) if needed a solution for the Contract First SOAP based services. Contract First services support is available with the help of spring-boot-starter-ws starter application. [Ref...] Externalised Configuration for properties and YAML Supports both Properties and YAML Supports both Properties and YAML Concluding Remarks If dealing with only REST micro services, drop wizard is an excellent choice. Where Spring-boot shines is the types of services supported i.e. REST, JMS, Messaging, and Contract First Services. Not least a fully built in Dependency Injection container. Disclaimer: The matrix is purely based on my personal views and experiences, having tried both frameworks and is by no means an exhaustive guide. Readers are requested to do their own research before making a strategic decision between the two very formidable frameworks.

Fellow geeks, the following article provides an overview of injection in Java EE and describes the two injection mechanisms provided by the platform: Resource Injection and Dependency Injection. Java EE provides injection mechanisms that enable our objects to obtain the references to resources and other dependencies without having to instantiate them directly (explicitly with ‘new’ keyword). We simply declare the needed resources & other dependencies in our classes by drawing fields or methods with annotations that denotes the injection point to the compiler. The container then provides the required instances at runtime. The advantage of Injection is that it simplifies our code and decouples it from the implementations of its dependencies. Note should be given for the fact that Dependency Injection is a specification (also a design pattern) and Context and Dependency Injection (CDI) is an implementation andJava standard for DI. The following topics are discussed here: · Resource Injection · Dependency Injection · Difference between Context and Dependency Injection 1. Resource Injection One of the simplification features of Java EE is the implementation of basic Resource Injection to simplify web and EJB components. Resource injection enables you to inject any resource available in the JNDI namespace into any container-managed object, such as a servlet, an enterprise bean, or a managed bean. For eg, we can use resource injection to inject data sources, connectors, or any other desired resources available in the JNDI namespace. The type we’ll use for the reference to the instance happen to be injected is usually an interface, which would decouple our code from the implementation of the resource. For better understanding of the above statement let’s take a look at the example. The resource injection can be performed in the following three ways: · Field Injection · Method Injection · Class injection Now, the javax.annotation.Resource annotation is used to declare a reference to a resource. So before proceeding, let’s learn few elements of @Resource annotation. @Resource has the following elements: · name: The JNDI name of the resource · type: The Java type of the resource · authenticationType: The authentication type to use for the resource · shareable: Indicates whether the resource can be shared · mappedName: A non-portable, implementation-specific name to which the resource should be mapped · description: The description of the resource Thenameelement is the JNDI name of the resource, and is optional for field- and method-based injection. For field injection, d defaultnameis the field name. For method-based injection, the defaultnameis the JavaBeans property name based on the method. The‘name’ and ‘type’element must be specified for class injection. Thedescriptionelement is the description of the resource (optional). Let’s hop on to the example now. Field Injection: To use field-based resource injection, declare a field and annotate it with the @Resource annotation. The container will refer the name and type of the resource if the name and type elements are not specified. If you do specify the type element, it must match the field’s type declaration. package com.example; public class SomeClass { @Resource private javax.sql.DataSource myDB; ... } In the code above, the container infers the name of the resource based on the class name and the field name: com.example.SomeClass/myDB. The inferred type isjavax.sql.DataSource.class. package com.example; public class SomeClass { @Resource(name="customerDB") private javax.sql.DataSource myDB; ... } In the code above, the JNDI name is customerDB, and the inferred type is javax.sql.DataSource.class. Method Injection: To use method injection, declare a setter method and preceding with the @Resource annotation. The container will itself refer the name and type of the resource if in case it is not specified by programmer. The setter method must follow the JavaBeans conventions for property names: the method name must begin with set, have a void return type, and only one parameter (needless to say :P). Anyways, if you do specify the return type, it must match the field’s type declaration. package com.example; public class SomeClass { private javax.sql.DataSource myDB; ... @Resource private void setMyDB(javax.sql.DataSource ds) { myDB = ds; } ... } In the code above, the container refers the name of the resource according to the class name and the field name: com.example.SomeClass/myDB. The type which is javax.sql.DataSource.class. package com.example; public class SomeClass { private javax.sql.DataSource myDB; ... @Resource (name="customerDB") private void setMyDB (javax.sql.DataSource ds) { myDB = ds; } ... } In the code above, the JNDI name is customerDB, and the inferred type is javax.sql.DataSource.class. Class Injection: To use class-based injection, decorate the class with a @Resource annotation, and set the requiredname and type elements. @Resource(name="myMessageQueue", type="javax.jms.ConnectionFactory") public class SomeMessageBean { ... } Declaring Multiple Resources The @Resources annotation is used to group together multiple @Resource declarations for class injection only. @Resources({ @Resource(name="myMessageQueue", type="javax.jms.ConnectionFactory"), @Resource(name="myMailSession", type="javax.mail.Session") }) public class SomeMessageBean { ... } The code above shows the @Resources annotation containing two @Resource declarations. One is a JMS (Java Messagin Service) message queue, and the other is a JavaMail session. 2. Dependency Injection Dependency injection enables us to turn regular Java classes into managed objects and to inject them into any other managed object (objects wich are managed by the container). Using DI, our code can declare dependencies on any managed object. The container automatically provides instances of these dependencies at the injection points at runtime, n it also manages the lifecycle of these instances right from class loading to releasing it for Garbage Collection. Dependency injection in Java EE defines scopes. For eg, a managed object that is only happen to respond to a single client request (such as a currency converter) has a different scope than a managed object that is needed to process multiple client requests within a session (such as a shopping cart). We can define managed objects (also called managed beans) so that we can later inject by assigning a scope to a needed class: @javax.enterprise.context.RequestScoped public class CurrencyConverter { ... } Use the javax.inject.Inject annotation to inject managed beans; for example: public class MyServlet extends HttpServlet { @Inject CurrencyConverter cc; ... } Umlike resource injection, dependency injection is typesafe because it resolves by type. To decouple our code from the implementation of the managed bean, we can reference the injected instances using an interface type and have our managed bean (regular class controlled by container) implement that interface. I wouldn’t like to discuss more on DI or better saying CDI since we already have a great article published on this. 3. Difference between Resource Injection and Dependency Injection The differences between the RI and DI are listed below. 1. Resource Injection can inject JNDI Resources directly whereas Dependency Injection cannot. 2. Dependency Injection can inject Regular Classes (managed bean) directly whereas Resource Injection cannot. 3. Resource Injection resolves by resource name whereas Dependency Injectin resolves by type. 4. Dependency Injection is typesafe whereas Resoiurce Injection is not. Conclusion: Thus we learnt concept on types on Injection in Java EE and the differences between them. Just a brief. There’s more to come

This article represents facts on what would it take to build one or more jar files for a given framework/library using Maven, provided the framework’s downloadable files consisted of pom.xml. Please feel free to comment/suggest if I missed to mention one or more important points. Also, sorry for the typos. So far, whenever I came across pom.xml file in the framework that I downloaded in order to get the jar file, I hated it. I used to, then, go to internet and get the compiled jar file(s) for the framework/library. And, good thing is that I have been able to get my work done. This was purely out of my laziness that I did not use to build using maven.Then, I got a chance to work with Twitter HBC library (Java) for integrating with Twitter. And, I downloaded it and wanted to get one or more jar files. And, once again, I came across apom.xml in root folder and unique pom.xml files in hbc-core, hbc-twitter4j and hbc-examples folder. This time, I decided to build the hbc jar files on my system.Following are some of the steps I took to build hbc jar files and get dependencies to run the program using hbc jar files. Download and install Maven. Anyone wanting to install/configure Maven, go to this Maven in 5 Minutes page. It clearly states what needs to be done to install/configure Maven. Once configured, open a command prompt and execute command “mvn -version”. If the version information of Maven is displayed, you are all set. Once determined, go to the folder which consists of pom.xml file. In present case, go to hbc root folder. Go to hbc root folder, hbc-master. Execute following command to build the hbc jar files and also obtain the dependencies (jar files) required to run the library. Command is “mvn clean install -U dependency:copy-dependencies“. This command built the source file and created two different jar files in hbc-twitter4j/target (hbc-twitter4j-2.2.1-SNAPSHOT.jar) and hbc-core/target (hbc-core-2.2.1-SNAPSHOT.jar). Further to that, it downloaded all the dependent jar files in repective target/dependency folder.

Converters are an essential building block in XAML interfaces with one simple task: converting values of one type to another. Since they have a input, usually a view model property, and an output, it would be wonderful if we could somehow chain them to create a new converter that processes all internal converters. Luckily, this is quite simple to do, but we do need to create a new converter which will hold other converters and whose implementation will iterate over nested converters. Full code can be found over at Github repository here, only interesting parts will be highlighted in this blog post. Our combining converter class is also a converter itself, but it can contain other converters inside it: [ContentProperty("Converters")] public class ChainingConverter : IValueConverter { public Collection Converters { get; set; } } Converter functions are trivially implemented and iteratively go through the converters list and apply the converter on the previous value. public object Convert(object value, Type targetType, object parameter, CultureInfo culture) { foreach (var converter in Converters) { value = converter.Convert(value, targetType, parameter, culture); } return value; } ConvertBack is implemented in the same fashion. This allows us to create new converters in XAML with the following syntax: But what if we need to send parameters to some of the converters, how can we do that when the same parameter is used throughout the ChainingConverter implementation? To provide custom parameter for individual converters, we can create a wrapper converter around existing converter and specify parameter on that wrapper. Here is a skeleton for such wrapper converter, notice that the wrapper is also a converter: [ContentProperty("Converter")] public class ParameterizedConverterWrapper : DependencyObject, IValueConverter { // IValueConverter Converter dependency property // object Parameter dependency property // object DefaultReturnValue dependency property public object Convert(object value, Type targetType, object parameter, CultureInfo culture) { if (Converter != null) return Converter.Convert(value, targetType, Parameter ?? parameter, culture); return DefaultReturnValue; } } Converter wrappers allow us to create complex converters such as this one: The final converter should be self explanatory even though you probably haven’t seen these converters before. You can see that unlike other converters, the wrapper is a dependency object which allows us to use bindings on the Parameter property since it is in fact a dependency property. More complex converters should be created from ordinary converters whenever possible, especially when working with primitive types such as bool, string, enums and null values. What’s next? The last example looked like a small DSL embedded in XAML. We could create converters that simulate flow control or conditionals. We could even create converters that switch depending on the property before it, essentially coding logic inside such converters. Whether that is desirable is debatable, but it can be done. The full code with sample application can be found at the following Github repository: MassivePixel/wp-common.

In this blog post I will look into the basics of configuring Role Based Access Control (RBAC) in EAP and Wildfly. RBAC was introduced in EAP 6.2 and WildFly 8 so you will need either of those if you wish to use RBAC. For the purposes of this blog I will be using the following: OS - Ubuntu 14 Java - 1.7.0_67 JBoss - EAP 6.3 Although I'm using EAP these instructions should work just the same on Wildfly. What is RBAC? Role Based Access Control is designed to restrict system access by specifying permissions for management users. Each user with management access is given a role and that role defines what they can and cannot access. In EAP 6.2+ and Wildfly 8+ there are seven predefined roles each of which has different permissions. Details on each of the roles can be found here: https://access.redhat.com/documentation/en-US/JBoss_Enterprise_Application_Platform/6.2/html/Security_Guide/Supported_Roles.html In order to authenticate users one of the three standard authentication providers must be used. These are: Local User - The local user is automatically added as a SuperUser so a user on the server machine has full access. This user should be removed in a production system and access locked down to named users. Username/Password - using either the mgmt-users.properties file, or an LDAP server. Client Certificate - using a trust store For the purposes of this blog and to keep things simple we will use username/passwords and the mgmt-users.properties file Why do we need RBAC? The easiest way to show this is through a practical demo. Configuration can be done either via the Management Console or via the Command Line Interface (CLI). However, only a limited set of tasks can be done via the management console whereas all tasks are available via the CLI. Therefore, for the purposes of this blog I will be doing all configuration via the CLI. In our test scenario we have 4 users: Andy - This user is the main sys-admin and therefore we want him to be able to access everything. Bob - This user is a lead developer and therefore will need to be able to deploy apps and make changes to certain application resources. Clare & Dave - These users are standard developers and will need to be able to view application resources but should not be able to make changes. First of all we will set up a number of users. In order to do so we will use the add-user.sh script which can be found in: /bin Create the following users in the stated groups. (Enter No for the final question for all users) Andy - no group Bob - lead-developers Clare - standard-developers Dave - standard-developers In /domain/configuration you will find a file called mgmt-users.properties. At the bottom of this file you will see a list of the users we've created similar to this: Andy=82153e0297590cceb14e7620ccd3b6ed Bob=06a61e836d9d2d5be98517b468ab72cc Clare=63a8ff615a122c56b1d47fc098ff5124 Dave=2df8d1e02e7f3d13dcea7f4b022d0165 In the same directory you will find a a file called mgmt-groups.properties, at the bottom of this file you will see a list of users and the groups they are in, like so: Andy= Bob=lead-developers Clare=developers Dave=developers Now point a browser at http://localhost:9990 and log in as the user Dave. Navigate around and you will see you have full access to everything. This is precisely why RBAC is needed! Allowing all users to not only access the management console but to be able to access and alter anything is a recipe for disaster and guaranteed to cause issues further down the line. Often users don't understand the implications of the changes they have made, it may just be a quick fix to resolve an immediate issue but it may have long term consequences that are not noticed until much further down the line when the changes that were made have been forgotten about or are not documented. As someone who works in support we see these kind of issues on a regular basis and they can be difficult to track down with no audit trail and users not realising that the minor change they made to one part of the system is now causing a major issue in some other part of the system. OK, so we now have our users set up but at the moment they have full access to everything. Next up we will configure these users and assign them to roles. First of all start up the CLI. Run the following command: /bin/jboss-cli.sh -c Change directory to the authorisation node cd /core-service=management/access=authorization Running the following command lists the current role names and the standard role names along with two other attributes ls -l The two we are interested in here are permission-combination-policy and provider. The permission-combination-policy defines how permissions are determined if a user is assigned more than one role. The default setting is permissive. This means that if a user is assigned to any role that allows a particular action then the user can perform that action. The opposite of this is rejecting. This means that if a user is assigned to multiple roles then all those roles must permit an action for a user to be able to perform that action. The other attribute of interest here is provider. This can be set to either simple (which is the default) or rbac. In simple mode all management users can access everything and make changes, as we have seen. In rbac mode users are assigned roles and each of those roles has difference privileges. Switching on RBAC OK, lets turn on RBAC... Run the following commands to turn on RBAC cd /core-service=management/access=authorization :write-attribute(name=provider, value=rbac) Restart JBoss Now point a browser at http://localhost:9990 and try to log in as the user Andy (who should be able to access everything). You should see the following message : Insufficient privileges to access this interface. This is because at the moment the user Andy isn't mapped to any role. Let's fix that now: If you look in domain.xml in the management element you will see the following: This shows that at the moment only the local user is mapped to the SuperUser role. Mapping users and groups to roles We need to map our users to the relevant roles to allow them access. In order to do this we need the following command: role-mapping=ROLENAME/include=ALIAS:add(name=USERNAME, type=USER) Where rolename is one of the pre-configured roles, alias is a unique name for the mapping and user is the name of the user to map. So, lets map the user Andy to the SuperUser role. ./role-mapping=SuperUser/include=user-Andy:add(name=Andy, type=USER) In domain.xml you will see that our user has been added to the SuperUser role: Now point a browser at http://localhost:9990 you should now be able to log in as the user Andy and have full access to everything. Next we need to add mappings for the other roles we want to use. ./role-mapping=Deployer:add ./role-mapping=Monitor:add Now we need to give role mappings to all our other users. As we have them in groups we can assign the groups to roles, rather than mapping by user. The command is basically the same as for a user but the type is GROUP rather than user. Here we are mapping lead developers to the Deployer role and standard developers to the Monitor role. ./role-mapping=Deployer/include=group-lead-devs:add(name=lead-developers, type=GROUP) ./role-mapping=Monitor/include=group-standard-devs:add(name=developers, type=GROUP) If you look in domain.xml you should now see the following showing that the user Andy is mapped to the SuperUser role and the two groups are mapped to the Deployer and Monitor roles. You can also view the role mappings in the admin console. Click on the Administration tab. Expand the Access Control item on the left and select Role Assignment. Select the Users tab - this shows users that are mapped to roles. Select the Groups tab and you will see the mapping between groups and roles. Log in as the different users and see the differences between what you can and can't access. Conclusion So, that's it for Part One. We have switched on RBAC, set up a number of users and groups and mapped those users and groups to particular roles to give them different levels of access. In Part Two of this blog I will look at constraints which allow more fine grained permission setting, scoped roles which allow you to set permissions on individual servers and audit logging which allows you to see who is accessing the management console and see what changes they are making.

this article represents different scenarios related with xss (cross-site scripting) and how to handle them appropriately using angularjs features such as sce ($sceprovider) and sanitize service ($sanitizeprovider) . please feel free to comment/suggest if i missed to mention one or more important points. also, sorry for the typos. following are the key xss-related scenarios described later in this article: escape html completely insert html in secure way while ignoring elements such as “script”. this is as well dangerous and could deface your website, if not taken care, especially with “img” tag. trust and insert entire html; this is dangerous and could easily end-up defacing your website escape html using ng-bind directive in case you want to escape html in entireity, you may want to use ng-bind directive. all it does is escape the html elements and print it as it is. following code demonstrates the ng-bind directive usage. angularjs xss demo test ng-bind directive: note that html text is entered as it is. {{hellomessage} following diagram demonstrates the above. pay attention to the html code entered in the text field. it is printed as it is, on to the html page. insert html in secure way, while ignoring elements such as “script”, using ng-bind-html directive this is key to solving xss attacks. that said, one should still take care of elements such as “img” ( included as part of white-list; void elements) as it could display any image (including illegal ones) on your webpage, thus, defacing your webpage . using ng-bind-html directive, javascript script tag such as “script” could be ignored straight-away. ng-bind-html directive evaluates the expression and inserts the resulting html into the element in a secure way. for cases where user inputs could consist of html (such as comments), the inclusion of ng-bind-html directive would ensure that the text is sanitize against a white-list of safe html tokens. the whitelist of safe tokens is coded as part of $sanitize module and mentioned below. following is included in the safe list (taken directly from the source code): void elements : area,br,col,hr,img,wbr. the details of same could be found at http://dev.w3.org/html5/spec/overview.html#void-elements block element : address,article,aside,blockquote,caption,center,del,dir,div,dl,figure,figcaption,footer,h1,h2,h3,h4, h5,h6,header,hgroup,hr,ins,map,menu,nav,ol,pre,script,section,table,ul inline elements : a,abbr,acronym,b,bdi,bdo,big,br,cite,code,del,dfn,em,font,i,img,ins,kbd,label,map,mark,q,ruby, rp,rt,s,samp,small,span,strike,strong,sub,sup,time,tt,u,var end tag elements : colgroup,dd,dt,li,p,tbody,td,tfoot,th,thead,tr,rp,rt. the details of same could be found at http://dev.w3.org/html5/spec/overview.html#optional-tags following are two elements which are escaped as it is in untrusted category . in case, you want to show it, you would have to use $sce service and call trustashtml method for angular to execute below-mentioned elements. script style following represents code sample demonstrating the ng-bind-html directive usage. angularjs xss demo test ng-bind-html directive: note that image is displayed appropriately as a result of text entered in the text field. following image demonstrates how it looks like when entering html code in textfield that is inserted into dom in a secure way. pay attention to “img” element which is a part of void elements in above list. as the code is entered in the textfield, the image appeared as “img” is in trusted list (white-list) trust and insert entire html warning: this is dangerous and could easily end-up defacing your website . only when you know and are doubly sure, you should use trustashtml. in case, you are confident that the text content could be trusted, you could use $sce service and call trustashtml method which then inserts entire html into the dom. pay attention to the html and javascript code snippet where $sce service is used to invoke trustashtml method to trust the html code. in that case, one code such as “” is inserted, it ended up painting already existing html element. this may not be healthy. one could change the background images with illegal images that way. ng-bind directive: note that html text is entered as it is. {{hellomessage} note that script tag is executed as well. following image demonstrates how it looks like when entering html style code in textfield that is inserted into dom . as a result, the other html element is painted in red as shown below. in scenarios where a hacker could insert an style element with background, this could show-up unwanted background and bring bad experience for the end users. entire code – cut/copy and paste and play angularjs xss demo test ng-bind directive: note that html text is entered as it is. {{hellomessage} note that script tag is executed as well. ng-bind-html directive: note that image is displayed appropriately as a result of text entered in the text field.

this article represents top 6 popular angularjs topics that has been used most by the angularjs developer community to date. the inference is derived based on number of tagged discussions happening on stackoverflow . clearly, “directive” is the winner and attracts most of them all. the article presents my thoughts on why these topics have been most popular. please feel free to comment/suggest if i missed to mention one or more important points. also, sorry for the typos. following is the list of top 6 popular topics: directives scope object ng-repeat angular ui & bootstrap routing service following plot demonstrates the popularity of different feature/topics in relation with angularjs. angularjs topics popularity inference : some of the following could as well be inferred from the above data/plot. three features which have been most used by the developers and therefore, should be key reasons why you would also want to use angular in next project are following: directives routing ng-repeat one of the pain point (or shortcoming) that have been talked most by the angular developers is the ui widgets related support by angular. this is where most of them have jumped to angular ui and bootstrap. the topic/concept that has intrigued most to several developers is scope object. thoughts on why these topics may be most popular following are top 6 popular topics in angularjs discussed on forums such as stackoverflow: directives : this is, no doubt, the most popular and powerful feature of angularjs directives as also indicated by count of discussion threads posted on stackoverflow as of today. the power of directives lies in the following and this is why it is the most popular topic of angularjs. re-usability : once created a directive as part of a module, all that one need to do to use the directive is include the module as a dependency when defining new module and define the directives wherever required on the page. usability : owing to the fact that one could give intuitive names to directives, directive enhances the readability and understandability of code by a notch. greater adherence to dry principle : the aspect of templating makes directive a very attractive feature. it does reduce the duplication of code as same html template code could be used at several places without the need to write the code in html file. scope object : this is second most popular topic found based on the discussion count. rightfully expected as well! the whole notion of scope object and how it is key to dependency injection makes it one of the most powerful as well as tricky concept of angularjs. also, this is one of the topic which raised the barrier to entry for angularjs and contributed in making steep learning curve for developers. that said, scope is going to r.i.p in angular 2.0 which could be seen as a good sign for those who always struggled with scope object. ng-repeat : the ng-repeat feature brings power to angularjs from the fact that it is one of the feature that removed the need of server-side code required to repeat the html code over multiple iterations. with ng-repeat, one could easily repeat html code multiple times. angular ui & bootstrap : one of the shortcoming of angularjs for good or bad is its inability to be one and all solution to create some great ui along with powerful eventing feature. for creating fancy or great looking ui, one would still have to go to ui frameworks such as bootstrap, kendo-ui etc. this is where people have been looking for angularui and bootstrap. angularui comes with attractive feature set for enhanced routing, grid util, angularjs code editor plugins, bootstrap module etc. routing : routing feature is key to creating single page application. one of key reason why angularjs is very popular is the ease with which one could create single-page application using it. and, routing feature makes it all happen. no doubt, this is why many developers have been looking for it. service : service feature helps one to create reusable components in an angular module. these services could then be injected in another modules using dependency injection feature. the service could be injected in one of the following components: controllers services doing a quick recap, one may recall that for creating a service, one could use factory recipe method and define service that way. you could know details about creating a custom service on our another page dedicated on this.

We can run a Gradle build without any of the task actions being executed. This is a so-called dry run of our build. We can use the dry run of a build to see if the task dependencies we have defined or are defined in a plugin are defined properly. Because all tasks and task dependencies are resolved if we use the dry run mode we can see in the output which tasks are executed. We define a simple build file with three tasks and some task dependencies: def printTaskNameAction = { println "Running ${it.name}" } task first << printTaskNameAction task second(dependsOn: first) << printTaskNameAction task third(dependsOn: [first, second]) << printTaskNameAction To run a Gradle build as a dry run we can use the command line option -m or --dry-run. So let's execute the task third with the dry run command line option: $ gradle -m third :first SKIPPED :second SKIPPED :third SKIPPED BUILD SUCCESSFUL Total time: 2.242 secs $ And we see in the output none of the tasks are really executed, because SKIPPED is shown, but we do see the task names of the tasks that are resolved. Written with Gradle 2.2.

One of the ways Spring recommends injecting inter-dependencies between beans is shown in the following sample copied from the Spring's reference guide here: @Configuration public class AppConfig { @Bean public Foo foo() { return new Foo(bar()); } @Bean public Bar bar() { return new Bar("bar1"); } } So here, bean `foo` is being injected with a `bar` dependency. However, there is one alternate way to inject dependency that is not documented well, it is to just take the dependency as a `@Bean` method parameter this way: @Configuration public class AppConfig { @Bean public Foo foo(Bar bar) { return new Foo(bar); } @Bean public Bar bar() { return new Bar("bar1"); } } There is a catch here though, the injection is now by type, the `bar` dependency would be resolved by type first and if duplicates are found, then by name: @Configuration public static class AppConfig { @Bean public Foo foo(Bar bar1) { return new Foo(bar1); } @Bean public Bar bar1() { return new Bar("bar1"); } @Bean public Bar bar2() { return new Bar("bar2"); } } In the above sample dependency `bar1` will be correctly injected. If you want to be more explicit about it, an @Qualifer annotation can be added in: @Configuration public class AppConfig { @Bean public Foo foo(@Qualifier("bar1") Bar bar1) { return new Foo(bar1); } @Bean public Bar bar1() { return new Bar("bar1"); } @Bean public Bar bar2() { return new Bar("bar2"); } } So now the question of whether this is recommended at all, I would say yes for certain cases. For eg, had the bar bean been defined in a different @Configuration class , the way to inject the dependency then is along these lines: @Configuration public class AppConfig { @Autowired @Qualifier("bar1") private Bar bar1; @Bean public Foo foo() { return new Foo(bar1); } } I find the method parameter approach simpler here: @Configuration public class AppConfig { @Bean public Foo foo(@Qualifier("bar1") Bar bar1) { return new Foo(bar1); } }

creating uber jar’s in java is nothing particular new, even creating executable jar’s was possible with maven long before java 8. with the first release of javafx 2, oracle introduced the javafxpackager tool, which has now been renamed to javapackager (java 8 u20). this enables developers to create native executables for any common platform, even mac app store packages; the drawbacks of the javapackager are that you must create the executable on the target platform and that it will than contain the whole jre to run the application. this means that your 100kb application gets more than 40mb, depending on your target platform. the first step on your way to an executable uber jar is to build your project and to collect all dependencies in a folder or a fat jar. this folder/fat jar will be the input for the javapackager tool, which creates the executable part. solution 1: the maven-dependency-plugin the maven-dependency-plugin contains the goal “unpack-dependencies”. we can use this goal to enhance the default “target/classes” folder with all the dependencies you need to run your application. we assume that the default maven build creates all classes of your project in the “target/classes” folder and the “unpack-dependencies” plugin copies all the project dependencies to this folder. the result is a valid input for the javapackager tool, which creates the executable. the “unpack-dependencies” goal is easy to use; you just need to set the output directory to the “target/classes” folder to ensure everything is together in one folder. a typical configuration looks like this: maven-dependency-plugin 2.6 unpack-dependencies package unpack-dependencies system org.springframework.jmx ${project.build.directory}/classes to create an executable jar from the target/classes directory we use the “exec-maven-plugin” to execute the javapackager commandline tool. org.codehaus.mojo exec-maven-plugin package-jar package exec ${env.java_home}/bin/javapackager -createjar -appclass ${app.main.class} -srcdir ${project.build.directory}/classes -outdir ./target -outfile ${project.artifactid}-app -v now we can create an executable jar, which contains all the project dependencies and that can simply be executed with “java –jar myapp.jar”. in the next step we want to create a native executable or an installer. specific configuration details for the javapackager can be found here: http://docs.oracle.com/javase/8/docs/technotes/tools/unix/javapackager.html , for this tutorial we assume that we want to create a native installer. to do so, we add a second “execution” to your “exec-maven-plugin” like this: package-jar2 package exec ${env.java_home}/bin/javapackager -deploy -native installer -appclass ${app.main.class} -srcfiles ${project.build.directory}/${artifactid}-app.jar -outdir ./target -outfile ${project.artifactid}-app -v once the configuration is done, you can run “mvn clean package” and you will find your executable jar as well as the native installer in your target folder. this solution works fine in most cases, but sometimes you can get in trouble with this plugin. when you have configuration files in your project that also exist in one of your dependencies, the unpack-dependency goal will overwrite your configuration file. for example your project contains a file like “meta-inf/service/com.myconf.file” and any dependency does contain the same file. in this case solution 2 may be a better approach. solution 2: the maven-shade plugin the maven-shade plugin provides the capability to package artifacts into an uber-jar, including its dependencies. it also provides various transformers to merge configuration files or to define the manifest of your jar file. this capability allows us to create an executable uber jar without involving the javapackager, so the packager is only needed to create the native executable. to build an executable uber jar following plugin configuration is needed: org.apache.maven.plugins maven-shade-plugin 2.3 package shade junit:junit jmock:* *:xml-apis … meta-inf/services/conf.file ${app.main.class} ${maven.compile.java.version} ${maven.compile.java.version} this configuration defines a main-class entry in the manifest and merges all “meta-inf/services/conf.files” together. the resulting executable jar file is now a valid input for the javapacker to create a native installer. the configuration to create a native installer with “exec-maven-plugin” and javapacker tool is exactly the same like in solution 1. i provided two example projects on github https://github.com/amoahcp/mvndemos where you can test both configurations. these are two simple projects with a main class starting a jetty webserver on port 8080, so the only dependency is jetty. both solutions can be used for any type of java projects, even with swing or javafx. reference: http://jacpfx.org/2014/10/08/uber-jars.html

Recently I ran into very interesting problem which I thought would take me just a couple of minutes to solve: protecting Apache CXF (current release 3.0.1)/ JAX-RS REST services with Spring Security (current stable version 3.2.5) in the application running inside embedded Jetty container (current release 9.2). At the end, it turns out to be very easy, once you understand how things work together and known subtle intrinsic details. This blog post will try to reveal that. Our example application is going to expose a simple JAX-RS / REST service to manage people. However, we do not want everyone to be allowed to do that so the HTTP basic authentication will be required in order to access our endpoint, deployed at http://localhost:8080/api/rest/people. Let us take a look on thePeopleRestService class: package com.example.rs; import javax.json.Json; import javax.json.JsonArray; import javax.ws.rs.GET; import javax.ws.rs.Path; import javax.ws.rs.Produces; @Path( "/people" ) public class PeopleRestService { @Produces( { "application/json" } ) @GET public JsonArray getPeople() { return Json.createArrayBuilder() .add( Json.createObjectBuilder() .add( "firstName", "Tom" ) .add( "lastName", "Tommyknocker" ) .add( "email", "a@b.com" ) ) .build(); } } As you can see in the snippet above, nothing is pointing out to the fact that this REST service is secured, just couple of familiar JAX-RS annotations. Now, let us declare the desired security configuration following excellent Spring Security documentation. There are many ways to configure Spring Security but we are going to show off two of them: using in-memory authentication and using user details service, both built on top of WebSecurityConfigurerAdapter. Let us start with in-memory authentication as it is the simplest one: package com.example.config; import org.springframework.beans.factory.annotation.Autowired; import org.springframework.context.annotation.Configuration; import org.springframework.security.config.annotation.authentication.builders.AuthenticationManagerBuilder; import org.springframework.security.config.annotation.method.configuration.EnableGlobalMethodSecurity; import org.springframework.security.config.annotation.web.builders.HttpSecurity; import org.springframework.security.config.annotation.web.configuration.EnableWebSecurity; import org.springframework.security.config.annotation.web.configuration.WebSecurityConfigurerAdapter; import org.springframework.security.config.http.SessionCreationPolicy; @Configuration @EnableWebSecurity @EnableGlobalMethodSecurity( securedEnabled = true ) public class InMemorySecurityConfig extends WebSecurityConfigurerAdapter { @Autowired public void configureGlobal(AuthenticationManagerBuilder auth) throws Exception { auth.inMemoryAuthentication() .withUser( "user" ).password( "password" ).roles( "USER" ).and() .withUser( "admin" ).password( "password" ).roles( "USER", "ADMIN" ); } @Override protected void configure( HttpSecurity http ) throws Exception { http.httpBasic().and() .sessionManagement().sessionCreationPolicy( SessionCreationPolicy.STATELESS ).and() .authorizeRequests().antMatchers("/**").hasRole( "USER" ); } } In the snippet above there two users defined: user with the role USER and admin with the roles USER,ADMIN. We also protecting all URLs (/**) by setting authorization policy to allow access only users with roleUSER. Being just a part of the application configuration, let us plug it into the AppConfig class using @Importannotation. package com.example.config; import java.util.Arrays; import javax.ws.rs.ext.RuntimeDelegate; import org.apache.cxf.bus.spring.SpringBus; import org.apache.cxf.endpoint.Server; import org.apache.cxf.jaxrs.JAXRSServerFactoryBean; import org.apache.cxf.jaxrs.provider.jsrjsonp.JsrJsonpProvider; import org.springframework.context.annotation.Bean; import org.springframework.context.annotation.Configuration; import org.springframework.context.annotation.DependsOn; import org.springframework.context.annotation.Import; import com.example.rs.JaxRsApiApplication; import com.example.rs.PeopleRestService; @Configuration @Import( InMemorySecurityConfig.class ) public class AppConfig { @Bean( destroyMethod = "shutdown" ) public SpringBus cxf() { return new SpringBus(); } @Bean @DependsOn ( "cxf" ) public Server jaxRsServer() { JAXRSServerFactoryBean factory = RuntimeDelegate.getInstance().createEndpoint( jaxRsApiApplication(), JAXRSServerFactoryBean.class ); factory.setServiceBeans( Arrays.< Object >asList( peopleRestService() ) ); factory.setAddress( factory.getAddress() ); factory.setProviders( Arrays.< Object >asList( new JsrJsonpProvider() ) ); return factory.create(); } @Bean public JaxRsApiApplication jaxRsApiApplication() { return new JaxRsApiApplication(); } @Bean public PeopleRestService peopleRestService() { return new PeopleRestService(); } } At this point we have all the pieces except the most interesting one: the code which runs embedded Jettyinstance and creates proper servlet mappings, listeners, passing down the configuration we have created. package com.example; import java.util.EnumSet; import javax.servlet.DispatcherType; import org.apache.cxf.transport.servlet.CXFServlet; import org.eclipse.jetty.server.Server; import org.eclipse.jetty.servlet.FilterHolder; import org.eclipse.jetty.servlet.ServletContextHandler; import org.eclipse.jetty.servlet.ServletHolder; import org.springframework.web.context.ContextLoaderListener; import org.springframework.web.context.support.AnnotationConfigWebApplicationContext; import org.springframework.web.filter.DelegatingFilterProxy; import com.example.config.AppConfig; public class Starter { public static void main( final String[] args ) throws Exception { Server server = new Server( 8080 ); // Register and map the dispatcher servlet final ServletHolder servletHolder = new ServletHolder( new CXFServlet() ); final ServletContextHandler context = new ServletContextHandler(); context.setContextPath( "/" ); context.addServlet( servletHolder, "/rest/*" ); context.addEventListener( new ContextLoaderListener() ); context.setInitParameter( "contextClass", AnnotationConfigWebApplicationContext.class.getName() ); context.setInitParameter( "contextConfigLocation", AppConfig.class.getName() ); // Add Spring Security Filter by the name context.addFilter( new FilterHolder( new DelegatingFilterProxy( "springSecurityFilterChain" ) ), "/*", EnumSet.allOf( DispatcherType.class ) ); server.setHandler( context ); server.start(); server.join(); } } Most of the code does not require any explanation except the the filter part. This is what I meant by subtle intrinsic detail: the DelegatingFilterProxy should be configured with the filter name which must be exactlyspringSecurityFilterChain, as Spring Security names it. With that, the security rules we have configured are going to apply to any JAX-RS service call (the security filter is executed before the Apache CXF servlet), requiring the full authentication. Let us quickly check that by building and running the project: mvn clean package java -jar target/jax-rs-2.0-spring-security-0.0.1-SNAPSHOT.jar Issuing the HTTP GET call without providing username and password does not succeed and returns HTTP status code 401. > curl -i http://localhost:8080/rest/api/people HTTP/1.1 401 Full authentication is required to access this resource WWW-Authenticate: Basic realm="Realm" Cache-Control: must-revalidate,no-cache,no-store Content-Type: text/html; charset=ISO-8859-1 Content-Length: 339 Server: Jetty(9.2.2.v20140723) The same HTTP GET call with username and password provided returns successful response (with some JSON generated by the server). > curl -i -u user:password http://localhost:8080/rest/api/people HTTP/1.1 200 OK Date: Sun, 28 Sep 2014 20:07:35 GMT Content-Type: application/json Content-Length: 65 Server: Jetty(9.2.2.v20140723) [{"firstName":"Tom","lastName":"Tommyknocker","email":"a@b.com"}] Excellent, it works like a charm! Turns out, it is really very easy. Also, as it was mentioned before, the in-memory authentication could be replaced with user details service, here is an example how it could be done: package com.example.config; import java.util.Arrays; import org.springframework.beans.factory.annotation.Autowired; import org.springframework.context.annotation.Bean; import org.springframework.context.annotation.Configuration; import org.springframework.security.config.annotation.authentication.builders.AuthenticationManagerBuilder; import org.springframework.security.config.annotation.method.configuration.EnableGlobalMethodSecurity; import org.springframework.security.config.annotation.web.builders.HttpSecurity; import org.springframework.security.config.annotation.web.configuration.EnableWebSecurity; import org.springframework.security.config.annotation.web.configuration.WebSecurityConfigurerAdapter; import org.springframework.security.config.http.SessionCreationPolicy; import org.springframework.security.core.authority.SimpleGrantedAuthority; import org.springframework.security.core.userdetails.User; import org.springframework.security.core.userdetails.UserDetails; import org.springframework.security.core.userdetails.UserDetailsService; import org.springframework.security.core.userdetails.UsernameNotFoundException; @Configuration @EnableWebSecurity @EnableGlobalMethodSecurity(securedEnabled = true) public class UserDetailsSecurityConfig extends WebSecurityConfigurerAdapter { @Autowired public void configureGlobal(AuthenticationManagerBuilder auth) throws Exception { auth.userDetailsService( userDetailsService() ); } @Bean public UserDetailsService userDetailsService() { return new UserDetailsService() { @Override public UserDetails loadUserByUsername( final String username ) throws UsernameNotFoundException { if( username.equals( "admin" ) ) { return new User( username, "password", true, true, true, true, Arrays.asList( new SimpleGrantedAuthority( "ROLE_USER" ), new SimpleGrantedAuthority( "ROLE_ADMIN" ) ) ); } else if ( username.equals( "user" ) ) { return new User( username, "password", true, true, true, true, Arrays.asList( new SimpleGrantedAuthority( "ROLE_USER" ) ) ); } return null; } }; } @Override protected void configure( HttpSecurity http ) throws Exception { http .httpBasic().and() .sessionManagement().sessionCreationPolicy( SessionCreationPolicy.STATELESS ).and() .authorizeRequests().antMatchers("/**").hasRole( "USER" ); } } Replacing the @Import( InMemorySecurityConfig.class ) with @Import( UserDetailsSecurityConfig.class ) in the AppConfig class leads to the same results, as both security configurations define the identical sets of users and their roles. I hope, this blog post will save you some time and gives a good starting point, as Apache CXF and Spring Security are getting along very well under Jetty umbrella! The complete source code is available on GitHub.

In my last post, I explained how to do code reviews properly. I recommended taking advantage of static analysis tools like Findbugs, PMD, Klocwork or Fortify to check for common mistakes and bad code before passing the code on to a reviewer, to make the reviewer’s job easier and reviews more effective. Some readers asked whether static analysis tools can be used instead of manual code reviews. Manual code reviews add delays and costs to development, while static analysis tools keep getting better, faster, and more accurate. So can you automate code reviews, in the same way that many teams automate functional testing? Do you need to do manual reviews too, or can you rely on technology to do the job for you? Let’s start by understanding what static analysis bug checking tools are good at, and what they aren’t. What static analysis tools can do – and what they can’t do In this article, Paul Anderson at GrammaTech does a good job of explaining how static analysis bug finding works, the trade-offs between recall (finding all of the real problems), precision (minimizing false positives) and speed, and the practical limitations of using static analysis tools for finding bugs. Static analysis tools are very good at catching certain kinds of mistakes, including memory corruption and buffer overflows (for C/C++), memory leaks, illegal and unsafe operations, null pointers, infinite loops, incomplete code, redundant code and dead code. A static analysis tool knows if you are calling a library incorrectly (as long as it recognizes the function), if you are using the language incorrectly (things that a compiler could find but doesn’t) or inconsistently (indicating that the programmer may have misunderstood something). And static analysis tools can identify code with maintainability problems, code that doesn't follow good practice or standards, is complex or badly structured and a good candidate for refactoring. But these tools can’t tell you when you have got the requirements wrong, or when you have forgotten something or missed something important – because the tool doesn't know what the code is supposed to do. A tool can find common off-by-one mistakes and some endless loops, but it won’t catch application logic mistakes like sorting in descending order instead of ascending order, or dividing when you meant to multiply, referring to buyer when it should have been seller, or lessee instead of lessor. These are mistakes that aren't going to be caught in unit testing either, since the same person who wrote the code wrote the tests, and will make the same mistakes. Tools can’t find missing functions or unimplemented features or checks that should have been made but weren't. They can’t find mistakes or holes in workflows. Or oversights in auditing or logging. Or debugging code left in by accident. Static analysis tools may be able to find some backdoors or trapdoors – simple ones at least. And they might find some concurrency problems – deadlocks, races and mistakes or inconsistencies in locking. But they will miss a lot of them too. Static analysis tools like Findbugs can do security checks for you: unsafe calls and operations, use of weak encryption algorithms and weak random numbers, using hard-coded passwords, and at least some cases of XSS, CSRF, and simple SQL injection. More advanced commercial tools that do inter-procedural and data flow analysis (looking at the sources, sinks and paths between) can find other bugs including injection problems that are difficult and time-consuming to trace by hand. But a tool can’t tell you that you forgot to encrypt an important piece of data, or that you shouldn't be storing some data in the first place. It can’t find logic bugs in critical security features, if sensitive information could be leaked, when you got an access control check wrong, or if the code could fail open instead of closed. And using one static analysis tool on its own to check code may not be enough. Evaluations of static analysis tools, such as NIST's SAMATE project (a series of comparative studies, where many tools are run against the same code), show almost no overlap between the problems found by different tools (outside of a few common areas like buffer errors) even when the tools are supposed to be doing the same kinds of checks. Which means that to get the most out of static analysis, you will need to run two or more tools against the same code (which is what SonarQube, for example, which integrates its own static analysis results with other tools, including popular free tools, does for you). If you’re paying for commercial tools, this could get very expensive fast. Tools vs. Manual Reviews Tools can find cases of bad coding or bad typing – but not bad thinking. These are problems that you will have to find through manual reviews. A 2005 study Comparing Bug Finding Tools with Reviews and Tests used Open Source bug finding tools (including Findbugs and PMD) on 5 different code bases, comparing what the tools found to what was found through code reviews and functional testing. Static analysis tools found only a small subset of the bugs found in manual reviews, although the tools were more consistent – manual reviewers missed a few cases that the tools picked up. Just like manual reviews, the tools found more problems with maintainability than real defects (this is partly because one of the tools evaluated – PMD – focuses on code structure and best practices). Testing (black box – including equivalence and boundary testing – and white box functional testing and unit testing) found fewer bugs than reviews. But different bugs. There was no overlap at all between bugs found in testing and the bugs found by the static analysis tools. Finding problems that could happen - or do happen Static analysis tools are good at finding problems that “could happen”, but not necessarily problems that “do happen”. Researchers at Colorado State University ran static analysis tools against several releases of different Open Source projects, and compared what the tools found against the changes and fixes that developers actually made over a period of a few years – to see whether the tools could correctly predict the fixes that needed to be made and what code needed to be refactored. The tools reported hundreds of problems in the code, but found very few of the serious problems that developers ended up fixing. One simple tool (Jlint) did not find anything that was actually fixed or cleaned up by developers. Of 112 serious bugs that were fixed in one project, only 3 were also found by static analysis tools. In another project, only 4 of 136 bugs that were actually reported and fixed were found by the tools. Many of the bugs that developers did fix were problems like null pointers and incorrect string operations – problems that static analysis tools should be good at catching, but didn’t. The tools did a much better job of predicting what code should be refactored: developers ended up refactoring and cleaning up more than 70% of the code structure and code clarity issues that the tools reported (PMD, a free code checking tool, was especially good for this). Ericsson evaluated different commercial static analysis tools against large, well-tested, mature applications. On one C application, a commercial tool found 40 defects – nothing that could cause a crash, but still problems that needed to be fixed. On another large C code base, 1% of the tool’s findings turned out to be bugs serious enough to fix. On the third project, they ran 2 commercial tools against an old version of a C system with known memory leaks. One tool found 32 bugs, another 16: only 3 of the bugs were found by both tools. Surprisingly, neither tool found the already known memory leaks – all of the bugs found were new ones. And on a Java system with known bugs they tried 3 different tools. None of the tools found any of the known bugs, but one of the tools found 19 new bugs that the team agreed to fix. Ericsson’s experience is that static analysis tools find bugs that are extremely difficult to find otherwise. But it’s rare to find stop-the-world bugs – especially in production code – using static analysis. This is backed up by another study on the use of static analysis (Findbugs) at Google and on the Sun JDK 1.6.0. Using the tool, engineers found a lot of bugs that were real, but not worth the cost of fixing: deliberate errors, masked errors, infeasible situations, code that was already doomed, errors in test code or logging code, errors in old code that was “going away soon” or other relatively unimportant cases. Only around 10% of medium and high priority correctness errors found by the tool were real bugs that absolutely needed to be fixed. The Case for Security So far we've mostly looked at static analysis checking for run-time correctness and general code quality, not security. Although security builds on code quality – vulnerabilities are just bugs that hackers look for and exploit – checking code for correctness and clarity isn’t enough for a secure app. A lot of investment in static analysis technology over the past 5-10 years has been in finding security problems in code, such as common problems listed in OWASP’s Top 10 or the SANS/CWE Top 25 Most Dangerous Software Errors. A couple of studies have looked at the effectiveness of static analysis tools compared to manual reviews in finding security vulnerabilities. The first study was on a large application that had 15 known security vulnerabilities found through a structured manual assessment done by security experts. Two different commercial static analysis tools were run across the code. The tools together found less than half of the known security bugs – only the simplest ones, the bugs that didn't require a deep understanding of the code or the design. And of course the tools reported thousands of other issues that needed to be reviewed and qualified or thrown away as false positives. These other issues including some run-time correctness problems, null pointers and resource leaks, and code quality findings (dead code, unused variables), but no other real security vulnerabilities beyond those already found by the manual security review. But this assumes that you have a security expert around to review the code. To find security vulnerabilities, a reviewer needs to understand the code (the language and the frameworks), and they also need to understand what kind of security problems to look for. Another study shows how difficult this is. Thirty developers were hired to do independent security code reviews of a small web app (some security experts, others web developers). They were not allowed to use static analysis tools. The app had 6 known vulnerabilities. 20% of the reviewers did not find any of the known bugs. None of the reviewers found all of the known bugs, although several found a new XSS vulnerability that the researchers hadn’t known about. On average, 10 reviewers would have had only an 80% chance of finding all of the security bugs. And, not Or Static analysis tools are especially useful for developers working in unsafe languages like C/C++ (where there is a wide choice of tools to find common mistakes) or dynamically typed scripting languages like Javascript or PHP (where unfortunately the tools aren't that good), and for teams starting off learning a new language and framework. Using static analysis is (or should be) a requirement in highly regulated, safety critical environments like medical devices and avionics. And until more developers get more training and understand more about how to write secure software, we will all need to lean on static analysis (and dynamic analysis) security testing tools to catch vulnerabilities. But static analysis isn't a substitute for code reviews. Yes, code reviews take extra time and add costs to development, even if you are smart about how you do them – and being smart includes running static analysis checks before you do reviews. If you want to move fast and write good, high-quality and secure code, you still have to do reviews.You can’t rely on static analysis alone.

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