Modular Web Applications based on OSGi - Jochen Hiller
- 1. 1 Modular web applications based on OSGi | March 18th 2008 | Short Talk #244 © Copyright 2008 Jochen Hiller; Source code in this presentation is made available under the EPL v1.0, remainder of the presentation is licensed under Creative Commons Att. Nc Nd 2.5 license Modular web applications based on OSGi Jochen Hiller March,18th 2008
- 2. Modular web applications based on OSGi | March 18th 2008 | Short Talk #244 © Copyright 2008 Jochen Hiller; Source code in this presentation is made available under the EPL v1.0, remainder of the presentation is licensed under Creative Commons Att. Nc Nd 2.5 license2 The OSGi HttpService … • is lightweight • is restricted to Servlet Spec 2.1 no filters, no listeners, no welcome-files no JSP support • requires registration at HttpService servlets / resources programmatically via extension point if using Equinox • Equinox provides techniques to add missing functionality see org.eclipse.equinox.http.helper classes from Simon Kaegi but: complex, additional effort required
- 3. Modular web applications based on OSGi | March 18th 2008 | Short Talk #244 © Copyright 2008 Jochen Hiller; Source code in this presentation is made available under the EPL v1.0, remainder of the presentation is licensed under Creative Commons Att. Nc Nd 2.5 license3 A solution: “Web Application Service” • The web.xml provides all configuration information • Parse web.xml to … register all servlets and filters from contributing bundle support specified welcome-files add JSP support by default add all mime-types, support default mime-types • Map web application to a context (alias in HttpService terms) • Resource lookup from contributing bundle • Binds to all OSGi HttpServices • The technique: register wrapper servlets • See https://bugs.eclipse.org/bugs/show_bug.cgi?id=162132
- 4. Modular web applications based on OSGi | March 18th 2008 | Short Talk #244 © Copyright 2008 Jochen Hiller; Source code in this presentation is made available under the EPL v1.0, remainder of the presentation is licensed under Creative Commons Att. Nc Nd 2.5 license4 Web Application Service: The Service API package org.eclipse.equinox.webapp.service; public interface WebAppService { public Object registerWebApp( String alias, Bundle bundle, String bundleResourcePath, String webXml, Dictionary options) throws WebContextException; public void unregisterWebApp(Object handle); }
- 5. Modular web applications based on OSGi | March 18th 2008 | Short Talk #244 © Copyright 2008 Jochen Hiller; Source code in this presentation is made available under the EPL v1.0, remainder of the presentation is licensed under Creative Commons Att. Nc Nd 2.5 license5 Web Application Service: As Extension point <!– web application service as extension point --> <extension id="webapp" name="DemoWebApp“ point="org.eclipse.equinox.webapp.registry.webapp"> <webapp alias="/" path="/WebContent"> </webapp> </extension>
- 6. Modular web applications based on OSGi | March 18th 2008 | Short Talk #244 © Copyright 2008 Jochen Hiller; Source code in this presentation is made available under the EPL v1.0, remainder of the presentation is licensed under Creative Commons Att. Nc Nd 2.5 license6 Web Application Service: As Extender pattern • Follows Extender Pattern as proposed by OSGi • Bundle Listener observes all bundles coming / leaving the platform • Trigger file is /WEB-INF/web.xml • Context to register is bundle symbolic name May be configured through /WEB-INF/osgi-web.xml
- 7. Modular web applications based on OSGi | March 18th 2008 | Short Talk #244 © Copyright 2008 Jochen Hiller; Source code in this presentation is made available under the EPL v1.0, remainder of the presentation is licensed under Creative Commons Att. Nc Nd 2.5 license7 What are the benefits? • Easy development of JavaEE based web applications based on OSGi • Simplified deployment of existing web applications (WAR) to OSGi • OSGi can act as a lightweight web container • Implementation is not dependent on OSGi runtime implementation
- 8. Modular web applications based on OSGi | March 18th 2008 | Short Talk #244 © Copyright 2008 Jochen Hiller; Source code in this presentation is made available under the EPL v1.0, remainder of the presentation is licensed under Creative Commons Att. Nc Nd 2.5 license8 Demo: Deploy Tomcat examples • Tomcat 5.5.x example applications servlet-examples jsp-examples • Changes required: Create /META-INF/MANIFEST.MF Added /WEB-INF/classes and /WEB-INF/lib/*.jar to bundle classpath May be automated using bnd tool from Peter Kriens
- 9. Modular web applications based on OSGi | March 18th 2008 | Short Talk #244 © Copyright 2008 Jochen Hiller; Source code in this presentation is made available under the EPL v1.0, remainder of the presentation is licensed under Creative Commons Att. Nc Nd 2.5 license9 Limitations, Plans • And what is missing? Taglib support is missing Listeners not yet supported Declarative security not supported Implementation under development, API may change Documentation, Tutorials More testing (e.g. compatibility with servlet bridge, other OSGi implementations) • Further ideas: Equinox specific framework extension to directly support loading WAR files Align with Enterprise OSGi and RFC 66 activities
- 10. Modular web applications based on OSGi | March 18th 2008 | Short Talk #244 © Copyright 2008 Jochen Hiller; Source code in this presentation is made available under the EPL v1.0, remainder of the presentation is licensed under Creative Commons Att. Nc Nd 2.5 license10 Questions? • Contact me: jo.hiller@googlemail.com • Incubator project at: http://sourceforge.net/projects/sse-examples CVS, webapp-incubator