Differences

This shows you the differences between two versions of the page.

Link to this comparison view

vaadin_7.4_osgi_web_application [2017/08/24 10:35]
 vaadin_7.4_osgi_web_application [2021/04/05 11:23] (current)
Line 1: Line 1:
 +====== Vaadin 7.4 OSGi Web Application ======
  
 +<note important>Editing not finished!</note>
 +
 +[[http://vaadin.com | Vaadin]] is a Servlet based Java web framework. And as most OSGi container support Servlet based web applications very well this should be a match made in heaven. But their are some minor things one will stumble upon when trying to run a Vaadin application inside an OSGi container. One of those things is always the classpath.
 +
 +
 +===== OSGi Web Application Packaging =====
 +OSGi Web Applications are called WAB ⇒ **W**eb **A**pplication **B**undle. Same as a bundle is just a jar file with an extended manifest file the same goes for the WAB. A web application bundle is just a WAR file with an extended manifest.
 +
 +
 +===== Demo Vaadin 7 OSGi Web Applicaton =====
 +The demo application is a stripped barebone Vaadin application. It uses the default widgetset and the default Vaadin Reindeer theme.
 +
 +It is derived from the Vaadin application maven archetype and just shows a button which will display a message on click.
 +
 +
 +===== Development =====
 +Maven and the Maven Bundle Plugin (and some other plugins) are used for development.
 +
 +==== Application Code ====
 +To get the application code from the source code repository just clone it with hg (Mercurial):
 +
 +  hg clone http://hg.code.sf.net/u/fist/demo.vaadin74 demo.vaadin74
 +
 +=== VaadinServlet ===
 +The VaadinServlet class is used to register the web application at the servlet container. Due to a classpath problem a class extending VaadinServlet must be created so that the bundle can resolve all needed classes.
 +
 +<sxh java title=OsgiVaadinServlet>
 +public class OsgiVaadinServlet extends VaadinServlet {
 +
 +    @Override
 +    protected VaadinServletService createServletService(DeploymentConfiguration deploymentConfiguration)
 +                    throws ServiceException {
 +
 +        VaadinServletService service = new VaadinServletService(this, deploymentConfiguration) {
 +
 +            @Override
 +            public ClassLoader getClassLoader() {
 +                return OsgiVaadinServlet.class.getClassLoader();
 +            }
 +
 +            @Override
 +            protected List<RequestHandler> createRequestHandlers() throws ServiceException {
 +                ClassLoader actual = Thread.currentThread().getContextClassLoader();
 +                try {
 +                    Thread.currentThread().setContextClassLoader(DefaultBroadcaster.class.getClassLoader());
 +                    return super.createRequestHandlers();
 +                }
 +                finally {
 +                    Thread.currentThread().setContextClassLoader(actual);
 +                }
 +            }
 +        };
 +        
 +        service.init();
 +        
 +        return service;
 +    }
 +}
 +</sxh>
 +
 +=== web.xml ===
 +The registration of the servlet is done via the //web.xml// file (annotations didn't work).
 +
 +<sxh xml>
 +<?xml version="1.0" encoding="UTF-8"?>
 +<web-app xmlns="http://java.sun.com/xml/ns/javaee" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
 + xsi:schemaLocation="http://java.sun.com/xml/ns/javaee
 +        http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd"
 + version="3.0">
 +
 + <servlet>
 + <servlet-name>vaadin_servlet</servlet-name>
 +
 + <servlet-class>test.vaadin74.OsgiVaadinServlet</servlet-class>
 +
 + <init-param>
 + <param-name>UI</param-name>
 + <param-value>test.vaadin74.MyVaadinUI</param-value>
 + </init-param>
 + </servlet>
 +
 + <servlet-mapping>
 + <servlet-name>vaadin_servlet</servlet-name>
 + <url-pattern>/*</url-pattern>
 + </servlet-mapping>
 +
 +</web-app>
 +</sxh>
 +
 +<note>Don't forget to specify your own VaadinServlet class in the web.xml file.</note>
 +
 +
 +=== Maven Bundle Plugin ===
 +The Maven Bundle Plugin takes care of all things related to the building of a bundle with the needed entries in the manifest file. Just add it to the pom.xml.
 +
 +<sxh xml>
 +<plugin>
 + <groupId>org.apache.felix</groupId>
 + <artifactId>maven-bundle-plugin</artifactId>
 + <version>2.5.4</version>
 + <extensions>true</extensions>
 + <executions>
 + <execution>
 + <id>bundle-manifest</id>
 + <phase>process-classes</phase>
 + <goals>
 + <goal>manifest</goal>
 + </goals>
 + </execution>
 + <execution>
 + <id>bundle-install</id>
 + <phase>install</phase>
 + <goals>
 + <goal>install</goal>
 + </goals>
 + </execution>
 + </executions>
 + <configuration>
 + <supportedProjectTypes>
 + <supportedProjectType>ejb</supportedProjectType>
 + <supportedProjectType>war</supportedProjectType>
 + <supportedProjectType>bundle</supportedProjectType>
 + <supportedProjectType>jar</supportedProjectType>
 + </supportedProjectTypes>
 + <instructions>
 + <!-- Read all OSGi configuration info from this optional file -->
 + <_include>-osgi.properties</_include>
 + <Bundle-PresentationName>${project.artifactId}</Bundle-PresentationName>
 + <Embed-Directory>WEB-INF/lib</Embed-Directory>
 + <Embed-Dependency>*;scope=compile</Embed-Dependency>
 + <Embed-Transitive>true</Embed-Transitive>
 + </instructions>
 + </configuration>
 +</plugin>
 +</sxh>
 +
 +=== MANIFEST.MF ===
 +The MANIFEST.MF file contains the information about the bundle or WAB. By default the MANIFEST.MF generated by the maven-bundle-plugin is located under ''WEB-INF/classes/META-INF''. To get these entries to the //normal// MANIFEST.MF maven needs some instructions.
 +
 +<sxh xml>
 +<plugin>
 + <!-- Need to use this plugin to build war files -->
 + <groupId>org.apache.maven.plugins</groupId>
 + <artifactId>maven-war-plugin</artifactId>
 + <version>2.6</version>
 + <configuration>
 + <archive>
 + <!-- add bundle plugin generated manifest to the war -->
 + <manifestFile>
 + ${project.build.outputDirectory}/META-INF/MANIFEST.MF
 + </manifestFile>
 + <!-- Adding Bundle-ClassPath in maven-bundle-plugin confuses that plugin 
 + and it generates wrong Import-Package, etc. So, we generate it here. -->
 + <manifestEntries>
 + <Bundle-ClassPath>WEB-INF/classes/</Bundle-ClassPath>
 + </manifestEntries>
 + </archive>
 + <!-- We don't always have a web.xml -->
 + <failOnMissingWebXml>false</failOnMissingWebXml>
 + </configuration>
 +</plugin>
 +</sxh>
 +
 +==== vaadinbootstrap.js ====
 +The file //vaadinbootstrap.js// is located in the //vaadin-server// jar in the folder //VAADIN//. The file should be copied from the vaadin-server jar to the folder ''src/main/webapp/VAADIN/''.
 +
 +==== Classpath ====
 +Vaadin expects some things to be on the classpath of the application, like themes and compiled resources. To get this working in a simple way is to include these in the war (see Embed-Dependency in pom.xml) and add them to the Bundle-ClassPath entry in the manifest file.
 +
 +  Bundle-ClassPath: .,WEB-INF/classes/,WEB-INF/lib/vaadin-themes-7.4.4.jar,WEB-INF/lib/vaadin-client-compiled-7.4.4.jar
 +  
 +===== Building =====
 +Building the web application bundle with maven is no more than doing a 
 +
 +  mvn clean package
 +
 +The "target" folder contains the bundle (war) file. 
 +
 +===== Deployment =====
 +
 +==== Apache Karaf ====
 +For the testing purpose I am using Apache Karaf 3.0.3 which is the latest stable version of Apache Karaf at the moment of writing and can be downloaded from the Apache Karaf website.
 +
 +Karaf is a very easy to manage OSGi container. Just unpack the archive and start it with
 +
 +  bin/karaf
 +
 +The bundles can be dumped into the deploy folder which will automatically start the bundles.
 +
 +=== Installing Prerequisites ===
 +
 +The //war// feature need to be installed with the command
 +
 +  feature:install war
 +  
 +Now drop all the dependencies into the deploy folder and you are ready to proceed.
 +
 +=== Installing Vaadin ===
 +Sadly not all libraries delivered with the Vaadin All-In-One archive are provided with a valid OSGi manifest header. But for most use cases a subset of libraries is sufficient enough. For this demo only the following libraries are needed:
 +    
 +  * flute-1.3.0.gg2.jar          
 +  * atmosphere-runtime-2.2.4.vaadin2.jar
 +  * org.apache.commons.beanutils-1.8.3.jar                
 +  * org.apache.commons.codec-1.8.0.jar           
 +  * org.apache.commons-collections-3.2.1.jar     
 +  * org.apache.commons.io-2.4.0.jar              
 +  * org.apache.commons.lang3-3.1.0.jar           
 +  * vaadin-slf4j-jdk14-1.6.1.jar
 +  * jsoup-1.8.1.jar                    
 +  * guava-16.0.1.vaadin1.jar              
 +  * streamhtmlparser-jsilver-0.0.10.vaadin1.jar
 +  * vaadin-shared-7.4.4.jar
 +  * vaadin-server-7.4.4.jar
 +  * vaadin-client-7.4.4.jar
 +
 +<note tip>Some of the libraries in the Vaadin archive have no OSGi manifest header entries, check for Bundle-* entries. OSGi versions of these libraries can be downloaded here (TODO) or from the [[http://search.maven.org | Maven Repository]].</note>
 +
 +=== Installing Demo ===
 +Just copy the test.vaadin-x.x.x.war to the deploy folder and you are done. The web application is available under the path which is specified in the manifest with the //Web-ContextPath//, in this example ''/test.vaadin7''.
 +
 +So point the browser to ''http://localhost:8181/test.vaadin7''.
 +=== Checking the web application ===
 +Apache Karaf uses Jetty as its HTTP server. By default it uses the port 8181. You can check this by either pointing your browser to http://localhost:8181 or by using netstat.
 +
 +  netstat -an | grep 8181
 +  
 +A good place to start looking for your application is always the log, see karaf/data/logs/karaf.log.
 +
 +Another nice method is by using the Apache Felix Webconsole. You can install it with ''feature:install webconsole''. Then go to http://localhost:8181/system/console/http . There you will see the installed WABs.
 +
 +
 +===== Stylesheet Compiling =====
 +If a CSS style is used or one of the predefined styles then everything is alright and should work. But if you are using your own style (or extending an existing one) then normally Vaadin would compile it on the fly during the first call of the servlet. But that ends in a nice error message.
 +
 +  java.lang.NoClassDefFoundError: com/vaadin/sass/internal/ScssStylesheet
 +  
 +But the Book of Vaadin explains nicely how to compile the stylesheet before the deployment.
 +
 +For myself the easiest way was to manually compile it with the following command
 +
 +  java -cp "/my/path/to/vaadin-all-7.4.4/lib/*":"/my/path/to/vaadin-all-7.4.4/*" com.vaadin.sass.SassCompiler styles.scss styles.css
 +
 +  
 +===== Open Questions =====
 +The Vaadin Push support has been tested in this setup. It may need some additional classes which has to be available on the bundle classpath.
 +
 +
 +===== Source Code =====
 +  * {{::pom.xml| Maven pom.xml file for OSGi Web Application Bundles}}
 +  * [[https://sourceforge.net/u/fist/test.vaadin7/ci/default/tree/ | Vaadin 7 OSGi Web App Test Case - Source Code Repository]]
 +
 +
 +===== Links =====
 +  * [[http://vaadin.com | Vaadin]]
 +  * [[https://vaadin.com/wiki/-/wiki/Main/Creating+a+Modular+Vaadin+Application+with+OSGi | Vaadin Wiki - Creating a Modular Vaadin Application with OSGi]]
 +  * [[http://felix.apache.org/site/apache-felix-maven-bundle-plugin-bnd.html | Maven Bundle Plugin]]
 +  * [[http://karaf.apache.org | Apache Karaf]]
 +
 +
 +{{tag>devel java vaadin osgi}}


  • Show page
  • Old revisions
  • Backlinks
  • Recent Changes
  • Media Manager
  • Sitemap