Integrating Restlet 2.0 with Spring

I recently spent hours trying to find out how to use the restlet 2.0 framework in combination with a Spring container. My main conclusion is that there is no straightforward documentation available on how to do this. Either the documentation is Restlet 1.1 specific or it is written in riddles rather than in a clear explanation with working samples.

[Edit] Given our experience with RESTeasy today, I would advice anyone to use the JBoss RESTeasy framework. I recently wrote an article on how to get RESTeasy up and running in combination with Spring on a Tomcat application server.

The Restlet Spring documentation page proposes two approaches: Restlet as the main container or Spring as the main container. Since we chose to handle security with Spring, we want Spring as the main container. Here is how this approach is configured.

In our project’s web.xml configuration, we added Spring’s ContextLoaderListener to enable Spring as the main container and we added Restlet’s SpringServerServlet as the main servlet entry point. It is important to configure the org.restlet.application parameter and point it to the Bean name that represents your Restlet Application.

<?xml version="1.0" encoding="UTF-8"?>
<web-app id="WebApp_ID" version="2.4"
xmlns="http://java.sun.com/xml/ns/j2ee"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://java.sun.com/xml/ns/j2ee http://java.sun.com/xml/ns/j2ee/web-app_2_4.xsd">
<display-name>Your project name</display-name>
<listener>
<listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>
</listener>
<context-param>
<param-name>contextConfigLocation</param-name>
classpath:applicationContext.xml
</context-param>
<servlet>
<servlet-name>rest</servlet-name>
<servlet-class>
org.restlet.ext.spring.SpringServerServlet
</servlet-class>
<init-param>
<param-name>org.restlet.application</param-name>
<param-value>application</param-value>
</init-param>
<load-on-startup>1</load-on-startup>
</servlet>
<servlet-mapping>
<servlet-name>rest</servlet-name>
/v1/*
</servlet-mapping>
</web-app>

In our applicationContext.xml file, we put the Bean definitions for our Restlet application and the router that handles the RESTfull requests. The RestletApplication class extends the Restlet Application class. Mind that there is no need to use classes from the com.noelios.restlet.ext.spring package, as many of the online examples suggest. Restlet 2.0 includes all that is needed to integrate with Spring.

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:util="http://www.springframework.org/schema/util"
xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-3.0.xsd http://www.springframework.org/schema/util http://www.springframework.org/schema/util/spring-util-3.0.xsd">
<bean id="router" class="org.restlet.ext.spring.SpringRouter">
<property name="attachments">
<map>
<entry key="/customers" value="com.company.resources.CustomerResource"/>
<entry key="/customer/{name}" value="com.company.resources.CustomerResource"/>
</map>
</property>
</bean>
<bean id="application" class="com.company.RestletApplication" scope="singleton">
<property name="root" ref="router"/>
</bean>
</beans>

For those people who use maven to fetch dependencies, here are our Restlet-specific maven dependencies:

<dependency>
<groupId>org.restlet</groupId>
<artifactId>org.restlet</artifactId>
<version>2.0-SNAPSHOT</version>
</dependency>
<dependency>
<groupId>org.restlet</groupId>
<artifactId>org.restlet.ext.servlet</artifactId>
<version>2.0-SNAPSHOT</version>
</dependency>
<dependency>
<groupId>org.restlet</groupId>
<artifactId>org.restlet.ext.json</artifactId>
<version>2.0-SNAPSHOT</version>
</dependency>
<dependency>
<groupId>org.restlet</groupId>
<artifactId>org.restlet.ext.spring</artifactId>
<version>2.0-SNAPSHOT</version>
</dependency>