Be RESTful on AEM6

JAX-RS(JSR311) is the JCP driven specification for creating REST styled webservices in java. There are use cases where content/service needs to be exposed to third parties, though AEM itself is rest driven there is no support for creating RESTful services. 

Jersey and OSGI can be brought together to provide restful service on AEM platform. jax-rs-connector is one such project that does this job and allows publishing Resources as OSGI service, the good thing is you can use all existing OSGI service via DI annotation @References.

The connector has a publisher bundle which  does this job via ServiceTracker mechanism i.e.  it tracks services having JAX-RS annotation(@Path, @Provider ) and hooks them into jersey i.e publishes as restful service.

AEM Implementation

To use it in AEM one needs to do following-:

 Clone the github project jax-rs-connector  and build the project or download jars from http://search.maven.org/#search|ga|1|g%3A%22com.eclipsesource.jaxrs%22 .

• Install jersey-all jar via osgi console.
• Install publisher jar and it's dependency  (JAX-RS Security Provider jar)
• Install (JAX-RS Gson Provider, Gson jar) for JSON response. (Optional)

Make sure all the installed bundles are active.

Now add some Resource as OSGI Service, as below :

1:    @Service   
2:    @Component(metatype = false)   
3:    @Path("/helloservice")   
4:    public class SampleResource {   
5:        
6:      //You can Refrence existing osgi service   
7:      //@Reference   
8:      //private MyService service;   
9:        
10:      @GET   
11:      @Path("/sayhi")   
12:      public String helloWorld() {   
13:        return "SampleResource says hi";   
14:      }     
15:       
16:      @GET      
17:      @Path("/getoperation")   
18:      @Produces({MediaType.TEXT_PLAIN})   
19:      public String getServiceOperation() {   
20:        String status = false;   
21:        //service.dosomething return   
22:        return status;   
23:      }   
24:    }  

Services are registered at /services path (configurable via osgi console) so the helloservice will be available at http://localhost:4502/services/helloservice/sayhi
Note: Tested on cq 6.0
References:

1. Step by Step: How to bring JAX-RS and OSGi together « EclipseSource Blog
2. hstaudacher/osgi-jax-rs-connector · GitHub