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JAX-RS (JSR-311)

Introduction

CXF supports JAX-RS (JSR-311), Java API for RESTful Web Services. JAX-RS standardizes the way RESTful services can be developed in Java.

CXF 2.3.0 supports JSR-311 API 1.1.
CXF 2.2.x supports JSR-311 API 1.0 .
CXF 2.3.0 and CXF 2.2.x have passed JAX-RS TCK 1.1 and TCK 1.0 respectively.

CXF 2.1.x supports JSR-311 API 0.8.

JAX-RS related demos are located under the samples/jax_rs directory.
This documentation will refer to JSR-311 API 1.1 .

Migration

Migrating from JAX-RS 0.8 to 1.0

The following major changes in 1.0 will most likely affect users migrating from 0.8

  • @ProduceMime and @ConsumeMime have been replaced with @Produces and @Consumes respectively
  • HttpHeaders has had some of its methods returning a string representation of Locale updated to return Locale instead

Migrating from 1.0 to 1.1

Existing JAX-RS 1.0 applications should run in CXF 2.3.0 without any problems.
There have been just few minor modifications at the JAX-RS API level :

  • @ApplicationPath has been introduced which JAX-RS Application implementations can be annotated with;
  • Request interface has been updated with a new evaluatePreconditions method with no input parameters - the existing applications which are already using the Request interface may need to be recompiled.

Maven dependencies

To incorporate JAX-RS, you will need:

   <dependency>
      <groupId>org.apache.cxf</groupId>
      <artifactId>cxf-rt-frontend-jaxrs</artifactId>
      <version>2.3.0</version>
   </dependency>

This will in turn pull in other CXF modules such cxf-api, cxf-rt-core, cxf-rt-transports-http and cxf-rt-bindings-xml as well as the following 3rd-party dependencies:

1. javax.ws.rs/jsr311-api/1.1 (or 1.0 for CXF 2.2.x)

2. org.apache.abdera groupId : abdera-core, abdera-parser and abdera-extensions-json artifacts, version 1.1. Note that starting from CXF 2.3.0 the Abdera dependencies are optional.

3. org.springframework/spring-core/3.0.5-RELEASE (and other core Spring dependencies)

4. org.codehaus.jettison/jettison/1.2

5. org.apache.xmlbeans/xmlbeans/2.4.0

Please check the pom.xml for the list of cxf components used by the JAX-RS implementation. Snapshots are available from http://repository.apache.org/snapshots/org/apache/cxf/apache-cxf/

Setting up the classpath in Eclipse or Ant

If Maven is not used then the following jars need to be available at the runtime classpath.

For CXF 2.3.0:

  • cxf-2.3.0.jar
  • jsr311-api-1.1.jar
  • jaxb-impl-2.1.13.jar
  • jaxb-api-2.1.jar
  • geronimo-annotation_1.0_spec-1.1.1.jar
  • geronimo-activation_1.1_spec-1.1.jar
  • geronimo-servlet_3.0_spec_1.0.jar
  • commons-logging-1.1.1.jar
  • geronimo-stax_api_1.0_spec-1.0.1.jar
  • woodstox-core-asl-4.0.8.jar
  • stax2-api-3.0.1.jar
  • wsdl4j-1.6.2.jar
  • XmlSchema-1.4.5.jar
  • neethi-2.0.4.jar

For CXF 2.2.x the dependencies are similar :

  • cxf-2.2.12.jar
  • jsr311-api-1.0.jar
  • do not add stax2-api-3.0.1.jar
  • add wstx-asl-3.2.8.jar instead of woodstox-core-asl-4.0.3.jar
  • add saaj-api-1.3.jar

If Spring configuration is used then add spring.jar from the Spring distribution or the spring jars available in the CXF distribution. When creating client proxies from concrete classes the cglib-nodep-2.1_3.jar needs to be added. You do not need to add JAXB libraries if you do not use JAXB. If you depend on Jetty then you will also need to add Jetty 7 or Jetty 6 jars shipped with CXF 2.3.0 and 2.2.12 respectively.

We will work on reducing the set of required dependencies.
Please see the configuration sections below on how a spring dependency can be dropped.

CXF JAX-RS bundle

A standalone JAX-RS bundle is now available which may be of interest to users doing JAX-RS work only.

Understanding the Basics

You are encouraged to read JAX-RS spec (html version) to find out information not covered by this documentation.

The JAX-RS introduces such terms as root resources, resource methods, sub-resources and sub-resource locators, message body readers and writers, etc.

Please see the JAX-RS Basics page for more information.

Support for Data Bindings

JAX-RS MessageBodyReader and MessageBodyWriter can be used to create data bindings for reading and writing the data in a number of different formats. Compliant JAX-RS implementations are expected to support JAXB-annotated beans, JAXP Source objects, InputStreams, etc.

In addition, CXF JAX-RS lets users reuse existing CXF DataBindings for working with JAXB, XBeans, Aegis and SDO.

Please see the JAX-RS Data Bindings page for more information.

Client API

JAX-RS 1.0 does not provide for the standard approach toward consuming pure HTTP-based services thus CXF JAX-RS provides a comprehensive support for developing RESTful clients by introducing 3 flavors of the client API : proxy-based, HTTP-centric and XML-centric.

Please see the JAX-RS Client API page for more information.

Support for Multiparts

Multiparts can be handled in a number of ways. CXF core runtimes provides an advanced support for handling attachments and CXF JAX-RS builds upon it.

Please see the JAX-RS Multiparts page for more information.

XPath and XSLT

XPath and XSLT are promoted and treated as first-class citizens in CXF JAX-RS. These technologies can be very powerful when generating complex data or retrieving data of interest out of complex XML fragments.

Please see the JAX-RS Advanced XML page for more information.

Support for Complex Search Queries

Using query parameter beans provides for a way to capture all the search requirements which can be expressed by enumerating simple name/value pairs, example, a query such as '?name=CXF&version=2.3' can be captured by a bean containing setName and setVersion methods. This 'template' bean can be used in the code to compare it against all the available local data.

CXF JAXRS (since 2.3) supports another option for users to do the advanced search queries based on the Feed Item Query Language(FIQL).

Please see the JAX-RS Advanced Features page for more information.

Debugging

One may want to use a browser to test how a given HTTP resource reacts to different HTTP Accept or Accept-Language header values and request methods. For example, if a resource class supports a "/resource" URI then one can test the resource class using one of the following queries :

> GET /resource.xml
> GET /resource.en

The runtime will replace '.xml' or '.en' with an appropriate header value. For it to know the type or language value associated with a given URI suffix, some configuration needs to be done. Here's an example how to do it in Spring :


  <jaxrs:server id="customerService" address="/">
    <jaxrs:serviceBeans>
      <bean class="org.apache.cxf.jaxrs.systests.CustomerService" />
    </jaxrs:serviceBeans>
    <jaxrs:extensionMappings>
      <entry key="json" value="application/json"/>
      <entry key="xml" value="application/xml"/>
    </jaxrs:extensionMappings>
    <jaxrs:languageMappings/>
  </jaxrs:server>

CXF also supports a _type query as an alternative to appending extensions like '.xml' to request URIs :

> GET /resource?_type=xml

Overriding a request method is also easy:

> GET /resource?_method=POST

Alternatively, one cam specify an HTTP header X-HTTP-Method-Override :

> POST /books
> X-HTTP-Method-Override : PATCH

For example, at the moment http-centric client API does not support arbitrary HTTP verbs except for those supported
by Java HTTPUrlConnection. When needed, X-HTTP-Method-Override can be set to overcome this limitation.

Please see the Debugging and Logging page for more information on how to debug and log the service calls in CXF.

Logging

Many of the existing CXF features can be applied either to jaxrs:server or jaxrs:client. For example, to enable the logging of requests and responses, simply do:

<beans xmlns:cxf="http://cxf.apache.org/core" 
 xsi:schemaLocation="http://cxf.apache.org/core http://cxf.apache.org/schemas/core.xsd">
<jaxrs:server>
<jaxrs:features>
     <cxf:logging/>
</jaxrs:features>
<jaxrs:server>
</beans>

Please make sure an "http://cxf.apache.org/core" namespace is in scope.

Starting from CXF 2.3.0 it is also possible to convert log events into Atom entries and either push them to receivers or make available for polling.

Please see the Debugging and Logging page for more information.

Filters, Interceptors and Invokers

It is possible to intercept and affect the inbound and outbound calls with the help of CXF JAX-RS filters and/or CXF interceptors. Additionally, custom invokers offer an option to intercept a call immediately before a service bean is invoked.

Please see the JAX-RS Filters page for more information.

Advanced Features

CXF JAX-RS provides a number of advanced extensions such as the support for the JMS transport, one-way invocations (HTTP and JMS), the suspended invocations (HTTP and JMS), making existing code REST-aware by applying the external user models, etc.

Please see the JAX-RS Advanced Features page for more information.

Secure JAX-RS services

A demo called samples\jax_rs\basic_https shows how to do communications using HTTPS.

It is often containers like Tomcat or frameworks like Spring Security which deal with ensuring a current user is authenticated. Sometimes you might want to do the custom authentication. The easiest way to do it is to register a custom invoker or RequestHandler filter which will extract a user name and password like this (it will work only for Basic Authentication requests) :

public class AuthenticationHandler implements RequestHandler {

    public Response handleRequest(Message m, ClassResourceInfo resourceClass) {
        AuthorizationPolicy policy = (AuthorizationPolicy)m.get(AuthorizationPolicy.class);
        policy.getUserName();
        policy.getPassword(); 
        // alternatively :
        // HttpHeaders headers = new HttpHeadersImpl(m);
        // access the headers as needed  

        // authenticate the user

        return null;
    }

}

A demo called samples\jax_rs\spring_security shows how to provide the authentication and authorization with the help of Spring Security.

Please see the [Security] section on how CXF Security interceptors can help. Check this blog entry for more information on how CXF JAX-RS wraps the CXF security interceptors with helper filters.

TODO : expand on it and possibly move to the dedicated page

Also see the "JAXRS and Spring AOP" section for some general advice.

SecurityManager and IllegalAccessExceptions

If java.lang.SecurityManager is installed then you'll likely need to configure the trusted JAX-RS codebase with a 'suppressAccessChecks' permission for the injection of JAXRS context or parameter fields to succeed. For example, you may want to update a Tomcat catalina.policy with the following permission :

grant codeBase "file:${catalina.home}/webapps/yourwebapp/lib/cxf.jar" {
    permission java.lang.reflect.ReflectPermission "suppressAccessChecks";
};

Redirection

Starting from CXF 2.2.5 it is possible to redirect the request or response call to other servlet resources by configuring CXFServlet or using CXF JAX-RS RequestDispatcherProvider.

Please see the JAX-RS Redirection page for more information.

Model-View-Controller support

XSLT
Please see this blog entry on how XSLTJaxbProvider can be used to generate complex (X)HTML views.

JSP

With the introduction of the RequestDispatcherProvider (see above) it is now possible for JAXRS service responses be redirected to JSP pages for further processing. Please see this beans.xml.

In addition to 'resourcePath' and 'dispatcherName' properties, one can set a 'scope' property which has two possible values, 'request' and 'session' with 'request' being the default value. It affects the way the JSP code can retrieve parameters passed to it by the RequestDispatcherProvider. If it is a 'request' scope then all the parameters are set as the attributes on the current HTTP request, if it is a session then they're set as the attributes on the current HTTP session.

RequestDispatcherProvider sets the following parameters :

  • JAXRS method response object, the name of this parameter is either a simple class name of this object (lower case) or a value retrieved from a beanNames map property using the fully qualified class name of this object.
  • All the path, query and matrix parameters which have been initialized during the method execution
  • "absolute.path", "base.path" and "relative.path" obtained from the current UriInfo

Service listings and WADL support

CXF JAX-RS supports WADL. CXF JAX-RS service endpoints can be listed in the service listings page and users can check the WADL documents.

Please see the JAXRS Services Description page for more information.

Configuring JAX-RS services

JAX-RS services can be configured programmatically, from Spring or using CXFNonSpringJAXRSServlet.

Please see the JAXRS Services Configuration page for more information.

Matching the Request URI

There's a number of variables involved here.

Lets assume you have a web application called 'rest'. CXFServlet's url-pattern is "/test/*". Finally, jaxrs:server's address is "/bar".

Requests like /rest/test/bar or /rest/test/bar/baz will be delivered to one of the resource classes in a given jaxrs:server endpoint. For the former request be handled, a resource class with @Path("/") should be available, in the latter case - at least @Path("/") or more specific @Path("/baz").

The same requirement can be expressed by having a CXFServlet with "/*" and jaxrs:server with "/test/bar".

When both CXFServlet and jaxrs:server use "/" then it's a root resource class which should provide a @Path with at least "/test/bar" for the above requests be matched.

Generally, it can be a good idea to specify the URI segments which are more likely to change now and then with CXFServlets or jaxrs:server.

Combining JAX-WS and JAX-RS

CXF JAX-RS tries to make it easy for SOAP developers to experiment with JAX-RS and combine both JAX-WS and JAX-RS in the same service bean when needed.

Please see the JAX-RS and JAX-WS page for more information.

JAX-RS and Spring AOP

CXF JAX-RS is capable of working with AOP interceptors applied to resource classes from Spring.
For example :


<beans xsi:schemaLocation=" http://www.springframework.org/schema/beans
  http://www.springframework.org/schema/beans/spring-beans.xsd
  http://www.springframework.org/schema/aop  
  http://www.springframework.org/schema/aop/spring-aop.xsd 
  http://cxf.apache.org/jaxrs 
  http://cxf.apache.org/schemas/jaxrs.xsd">
  <import resource="classpath:META-INF/cxf/cxf.xml"/>
  <import resource="classpath:META-INF/cxf/cxf-extension-jaxrs-binding.xml"/>
  <import resource="classpath:META-INF/cxf/cxf-servlet.xml"/>

  <jaxrs:server id="bookservice" address="/">
	<jaxrs:serviceBeans>
          <ref bean="bookstore"/>
          <ref bean="bookstoreInterface"/>
        </jaxrs:serviceBeans>
   </jaxrs:server>
   <bean id="bookstore" class="org.apache.cxf.systest.jaxrs.BookStore"/>
   <bean id="bookstoreInterface" class="org.apache.cxf.systest.jaxrs.BookStoreWithInterface"/>

   <aop:config>
	<aop:aspect id="loggingAspect" ref="simpleLogger">
          <aop:before method="logBefore" pointcut="execution(* org.apache.cxf.systest.jaxrs.BookStore*.*(..))"/>
          <aop:after-returning method="logAfter" pointcut="execution(* org.apache.cxf.systest.jaxrs.BookStore*.*(..))"/>
        </aop:aspect>
   </aop:config>
   <bean id="simpleLogger" class="org.apache.cxf.systest.jaxrs.SimpleLoggingAspect"/>
</beans>

Note that some AOP configuration is applied to two JAX-RS resource classes. By default Spring uses JDK dynamic proxies every time a class to be proxified implements at least one interface or CGLIB proxies otherwise.

For example, here's how org.apache.cxf.systest.jaxrs.BookStoreWithInterface looks like : 


public interface BookInterface {
    @GET
    @Path("/thosebooks/{bookId}/")
    @Produces("application/xml")
    Book getThatBook(Long id) throws BookNotFoundFault;
}

public class BookStoreWithInterface extends BookStoreStorage implements BookInterface {

    public Book getThatBook(@PathParam("bookId") Long id) throws BookNotFoundFault {
        return doGetBook(id);
    }

    @Path("/thebook")
    public Book getTheBook(@PathParam("bookId") Long id) throws BookNotFoundFault {
        return doGetBook(id);
    }
}

In this case Spring will use a JDK proxy to wrap a BookStoreWithInterface class. As such it is important that a method which needs to be invoked such as getThatBook(...) is part of the interface.

The other method, getTheBook() can not be dispatched to by a JAX-RS runtime as it's not possible to discover it through a JDK proxy. If this method also needs to be invoked then this method should either be added to the interface or CGLIB proxies have to be explicitly enabled (consult Spring AOP documentation for more details). For example :

<aop:config proxy-target-class="true"/>

Integration with Distributed OSGi

Distributed OSGi RI is a CXF subproject. DOSGi mandates how registered Java interfaces can be exposed
and consumed as remote services. DOSGi single and multi bundle distributions contain all the OSGI bundles required for a CXF endpoint be successfully published.

CXF JAX-RS implementations has been integrated with DOSGi RI 1.1-SNAPSHOT which makes it possible to expose Java interfaces as RESTful services and consume such services using a proxy-based client API.

Please see DOSGI Reference page ('org.apache.cxf.rs' properties) and a greeter_rest sample for more information. Note that this demo can be run exactly as a SOAP-based greeter demo as it registers and consumes a similar (but) JAX-RS annotated GreeterService. In addition, this demo shows how one can register and consume a given interface (GreeterService2) without using explicit JAX-RS annotations but providing an out-of-band user model description.

How to contribute

CXF JAX-RS implementation sits on top of the core CXF runtime and is quite self-contained and isolated from other CXF modules such as jaxws and simple frontends.

Please check this list and see if you are interested in fixing one of the issues.

If you decide to go ahead then the fastest way to start is to

  • do the fast trunk build using 'mvn install -Pfastinstall'
  • setup the workspace 'mvn -Psetup.eclipse' which will create a workspace in a 'workspace' folder, next to 'trunk'
  • import cxf modules from the trunk into the workspace and start working with the cxf-frontend-jaxrs module

If you are about to submit a patch after building a trunk/rt/frontend/jaxrs, then please also run JAX-RS system tests in trunk/systests/jaxrs :
> mvn install

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