I have a number of classes exposed as JAX-RS request "handlers", using javax.ws.rs.Path annotations. I want to add certain actions before every request and after each request. Also, I need to create a global application-wide exception handler, which will catch everything thrown by these handlers and protocol.
Is it possible to achieve this with standard JAX-RS without creating of a custom class inherited from com.sun.jersey.spi.container.servlet.ServletContainer (I'm using Jersey).
You can also use ExceptionMappers. This mechanism which catch the exception thrown by your service and convert it to the appropriate Response:
@Provider
public class PersistenceMapper implements ExceptionMapper<PersistenceException> {
@Override
public Response toResponse(PersistenceException arg0) {
if(arg0.getCause() instanceof InvalidDataException) {
return Response.status(Response.Status.BAD_REQUEST).build();
} else {
...
}
}
}
For more information see:
You could create a proxy RESTful service and use this as the entry point to all your other RESTful services. This proxy can receive requests, do any pre-processing, call the RESTful service required, process the response and then return something to the caller.
I have a set up like this in a project I've been working on. The proxy performs functions like authentication, authorisation and audit logging. I can go into further details if you like.
Edit:
Here is an idea of how you might want to implement a proxy that supports GET requests;
@Path("/proxy")
public class Proxy
{
private Logger log = Logger.getLogger(Proxy.class);
@Context private UriInfo uriInfo;
@GET
@Path("/{webService}/{method}")
public Response doProxy(@Context HttpServletRequest req,
@PathParam("webService") String webService,
@PathParam("method") String method)
{
log.debug("log request details");
//implement this method to work out the URL of your end service
String url = constructURL(req, uriInfo, webService, method);
//Do any actions here before calling the end service
Client client = Client.create();
WebResource resource = client.resource(url);
try
{
ClientResponse response = resource.get(ClientResponse.class);
int status = response.getStatus();
String responseData = response.getEntity(String.class);
log.debug("log response details");
//Do any actions here after getting the response from the end service,
//but before you send the response back to the caller.
return Response.status(status).entity(responseData).build();
}
catch (Throwable t)
{
//Global exception handler here
//remember to return a Response of some kind.
}
}
