building server-side eclipse based web applications

Building Server-Side Eclipse based web applications | Tutorial© Copyright 2007, 2008, 2009 Jochen Hiller, Simon Kaegi, Gunnar Wagenknecht, IBM Corporation; 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 license1

Building Server-Side Eclipse based web applications

Tutorial

Building Server-Side Eclipse based web applications | Tutorial© Copyright 2007, 2008, 2009 Jochen Hiller, Simon Kaegi, Gunnar Wagenknecht, IBM Corporation; 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

The authors

Jochen HillerDeutsche Telekom AG, [email protected]

Simon KaegiIBM Rational Software, [email protected], E4 Committer

Gunnar WagenknechtAGETO, [email protected] Committer

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mailto:[email protected]




Overview

• Introduction to Server-Side Eclipse

• Developing Server-Side Eclipse applications

• Deploying Server-Side Eclipse applications

• Monitoring and Debugging Server-Side Eclipse applications

• Summary

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What is Server-Side Eclipse (SSE)?• Recognition… that many of the features that have made RCP successful are

equally applicable in server-side contexts.Standardized component model (OSGi)Pervasive extensibility – Extension RegistryRuntime provisioning

• Integration... with existing server-side infrastructure and technologiesJ2EE Application ServersServlets and JSPsApplication Frameworks…

• Jeff McAffer stated at EclipseCon 2007, Equinox BOF:Server-Side Eclipse is a concept, a marketing name, to illustrate possible usage scenarios (like RCP).

• The new top level project Eclipse Runtime is an umbrella project for a lot of server-related projects

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What motivates developers to use SSE?

JavaTM EEapplication

RCPapplication

+ component model+ use 3rd party plug-ins

Web developer

+ server support+ re-use plugins+ distributed

applications

RCP developer

applicationframework

+ component model• modular• flexible• dynamic

Infrastructure developer

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SSE Based Web Applications

• Component based (Bundles)

• Use the OSGi HttpService (Servlet API)Explicitly (code) or declaratively (extension registry)

• Consistent development story independent of deployment constraints

Support for an embedded HttpServiceSupport for running embedded in Application Servers

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Overview





• Summary

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Integrating Java EE with the OSGi HttpService

• Replaces web deploy descriptor (e.g. “web.xml”)• URL mapping differences• Servlet API support

ServletContext / HttpContext differencesDoes not provide “direct” support for Filters, Listeners.

• Dynamic Registrationvoid registerResources(String alias, String name, HttpContext context) void registerServlet(String alias, Servlet servlet, Dictionary initparams, HttpContext context)void unregister(String alias)

http://www2.osgi.org/javadoc/r4/org/osgi/service/http/HttpService.html#registerResources(java.lang.String, java.lang.String, org.osgi.service.http.HttpContext)

http://www2.osgi.org/javadoc/r4/org/osgi/service/http/HttpContext.html


http://www2.osgi.org/javadoc/r4/org/osgi/service/http/HttpService.html#unregister(java.lang.String)


URL Mapping Differencesvoid registerResources(String alias, String name, HttpContext context)

• “alias” roughly equivalent to <url-mapping>alias of “/myContent” is equivalent to <url-mapping>

/myContent/*</url-mapping>

• “name” provides a base path when looking up resources in the HttpContext.

• No support for extension mappings

• No implicit welcome file supporteg. mapping “/” to “/index.html”

Supported in Equinox

Syntax is:{path}/*.jsp

http://www2.osgi.org/javadoc/r4/org/osgi/service/http/HttpService.html#registerResources(java.lang.String, java.lang.String, org.osgi.service.http.HttpContext)



HttpContext• Maps 1-1 to a ServletContext

• Allows implementation of custom HttpContext

• MIME type retrieval • resource retrieval• authentication

• Does not directly support:getNamedDispatchergetResourcePathsgetInitParameters (*)“Context Path” (*)

Method Summary

String getMimeType(String name)

URL getResource(String name)

boolean handleSecurity(HttpServletRequest request, HttpServletResponse response)

Supported in Equinox (via Reflection)

Set getResourcePaths(String path)

http://www2.osgi.org/javadoc/r4/org/osgi/service/http/HttpContext.html#getMimeType(java.lang.String)

http://www2.osgi.org/javadoc/r4/org/osgi/service/http/HttpContext.html#getResource(java.lang.String)

http://www2.osgi.org/javadoc/r4/org/osgi/service/http/HttpContext.html#handleSecurity(javax.servlet.http.HttpServletRequest, javax.servlet.http.HttpServletResponse)

http://tomcat.apache.org/tomcat-5.5-doc/servletapi/javax/servlet/ServletContext.html#getResourcePaths(java.lang.String)


Servlets and FiltersWhat’s missing…

• Filter (*)

• HttpSessionListener• HttpSessionAttributeListener• HttpSessionActivationListener

• ServletContextListener (*)• ServletContextAttributeListener

• ServletRequestListener• ServletRequestAttributeListener

(*) = Workarounds Available:

• Technique is to wrap-and-adapt your Servlet or Resource.

Servlet wrapped = new ContextListenerServletAdaptor(

myServlet, myListener);registerServlet(“/myPath”, wrapped, params, myHttpContext);

• See org.eclipse.equinox.http.helper[s]in the Equinox-Incubator CVS

• not currently API but supported


Dynamic RegistrationTwo main techniques:• Code-based

Lifecycle: tied to Bundle START and STOPMore Complex but provides greater control

• Extension Registry (org.eclipse.equinox.http.registry)Lifecycle: tied to Bundle RESOLVED and UNRESOLVEDSimpler in most cases

• Declarative Services / Spring

URL Space is also dynamic and shared across all registrationsNo more than one registration per “alias”Worth planning – useful techniques with relative URLs


JSP Support

• Provided by:org.eclipse.equinox.jsp.jasper.JspServlet

<< public JspServlet(Bundle bundle, String bundleResourcePath, String alias) >>

• No default constructor

• Requires compilation / runtime context from “bundle”• JSP lookup consistent with OSGi HttpService resource

registration.

JSP Support – Extension Registry• Extension Registry Support provided by:

org.eclipse.equinox.jsp.jasper.registry.JspFactory• ExecutableExtensionFactory



<extensionpoint="org.eclipse.equinox.http.registry.servlets">

<servletalias="/myPath/*.jsp“class="org.eclipse.equinox.jsp.jasper.registry.JSPFactory:/bundlePath">

</servlet></extension>

• Use “{path}/*.jsp” style alias for JSPs.Allows a “{path}” resource registration to support more efficiently serving static resources without an alias namespace collision.


Exercises

• Start Eclipse & configure target platform• Hello Servlet• Hello JSP• Hello Servlet Registry• Hello JSP Registry

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Overview





• Summary

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Recommended deployment scenarios

Deployment depends on target infrastructure:

• Standalone Equinox server applicationEmbedded HttpServiceLightweight solution – good choice for developmentDistribute like Eclipse RCP application

• Run application in External Application ServerRecommended as production solutionDeploy as standard WAR application (scripts provided)

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Equinox embedding an HttpService• Run Equinox as standalone application• Multiple processes isolated• Embedded HttpService (e.g. Jetty)• Application functionality based on bundles, Servlets, JSPs, ...• Add web services as bundle• Server management based on bundles

Source: Jeff McAffer, Eclipse Summit Europe, Server-Side Symposium, Oct 12nd 2006

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Deploying standalone Equinox server

• Choose target platform• Add platform specific launchers if required• Add common services and bundles (see Eclipse Orbit!)• Add application plug-ins• Group bundles / plug-ins as features

Application plug-ins

Common services(see Orbit)

Server-Side EclipseEquinox

Operating System

Jetty

Servlet JSP

Jasper

Bundles

commons-logging, ...

...

3rdParty UpdateConfigurator

...

Laun

cher

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Deploying Standalone Equinox server• Deploy like an RCP application

Plugins / Feature / Product based exportYou have to include SSE related pluginsMaintain config.ini for starting bundles

• Important config.ini settings:osgi.console=true # start an OSGi consoleosgi.noShutdown=true # do NOT shutdown OSGieclipse.ignoreApp=true # do NOT start an Eclipse application

• Or use commandline arguments when using Eclipse starter:-console # enable OSGi console-noExit # same as osgi.noShutdown=true-application <id> # start application with <id>

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Deploy Standard Equinox – Running the Server

•Start Equinox serverjava –Dorg.osgi.service.http.port=8080 \

–jar plugins\org.eclipse.equinox.launcher_<version>.jar \–console -noExit

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Application Server running an embedded Equinox

• Launch Equinox in traditional application server• Isolation between multiple web applications/Equinox instances• Forwarding (Lite) HttpService exposes application server

capabilities• Application functionality based on bundles, Servlets, JSPs, ...• Bridging aspect is referred to as the Servletbridge

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What is the Servletbridge?

Servlet - side• Eclipse framework launcher• Bridge Servlet with a call-back

registration point

OSGi - side• Proxy Servlet that registers with

Bridge Servlet• OSGi HttpService

Servlet OSGi

… a bridge between the servlet and OSGi world

Framework Launcher HttpService

Proxy ServletBridge Servlet1

2

3

4

5

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What is the Servletbridge?

Servletbridge

Servlet OSGi

Incoming Request Registered Request Handler

OSGi HttpServiceregisterResource(…)

registerServlet(…)

Incoming requests are “proxied” through the Servletbridge to registered request handlers.

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Deploying Equinox Inside an Application Server

• Deploy similar to an RCP application but in a Web Archive/WEB-INF

/web.xml (with one servlet entry assigning all incoming requests to the BridgeServlet) /lib/servletbridge.jar (the classes associated with the equinox.servletbridge) /eclipse (the eclipse platform directory)

launch.ini (contains framework properties that will allow override of any eclipse specific System Properties)

/configuration (contains config.ini which lists the bundles you want to have available at startup)

/features /plugins

• org.eclipse.equinox.servletbridge Project/scripts/webappBuilder.xml (Ant Script for building WAR file)/templates (contains the WAR directory structure)

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Deploying Equinox inside Application Server

• Online Demo

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Exercises

• Create feature for build/export• Export standalone server using product export• Create & deploy WAR file using Servlet bridge

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Overview





• Summary

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Logging in Equinox Jetty 6 Integration

• Jetty logging now controllable in 3.5

• -Dorg.eclipse.equinox.http.jetty.log.stderr.threshold=<level>

"debug", "info", "warn", "error", and "off“Default is “warn”

• Log will happen to STDERR only (for now)

• Outlook: deeper integration with Extended Equinox Log Service (3.6)

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Debugging: Where to hook in

•Hook either inOSGi worldServetBridge

•Startup problems:FrameworkLauncher

•Central access: ProxyServlet

Hook in processAlias

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Servlet Bridge Management Commands

“web.xml” allows configuration of initial parameters:• commandline Allows all non-VM command line parameterizations of Eclipse.

The default value is "-console“ which should be cleared for production.• enableFrameworkControls (true / false) - Controls whether or not the sp_* control URLs are

accessiblesp_deploy - Copies the contents of /platform to the install area (the servlet context tempdir is used -parameterizable someday) sp_undeploy - Removes the copy of Eclipse from the install area sp_redeploy - Resets the platform (e.g. stops, undeploys, deploys, starts) sp_start - Starts a deployed platform sp_stop - Stops the platform sp_test - Provides a sanity check and determines if an OSGi based servlet is ready to accept requests

• frameworkLauncherClass – allows customization of the launcher• extendedFrameworkExports – additional java package exports from the web application.

Servlet API is automatically exported.

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Knopflerfish HTTP Console

• Provides convenient way to manage bundles at runtime

• Works within Servlet Bridge

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Overview





• Summary

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Summary - Looking forward...• Eclipse >3.3 supports building OSGi based web applications for:

Equinox based RCP and headless applicationsEquinox embedded in an application server

• Outlook for Eclipse 3.5Jetty 6

• Jetty joined Eclipse much tigther integration expected

• Outlook for OSGi Spec workEnterprise Expert GroupHttp Service according 2.5 Spec“WebContainer” alike support, but with OSGi dynamics

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For more information...

Project hub:http://www.eclipse.org/equinox/server

Newsgroup:news://news.eclipse.org/eclipse.technology.equinox

Dev Mailing List:[email protected]

Thank-you

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http://www.eclipse.org/equinox/server

news://news.eclipse.org/eclipse.technology.equinox



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building server-side eclipse based web applications

Technology

existing server

license1building server

lot of server

committer2building server

eclipse sse

ibm corporation source

simon kaegi

creative commons