@Provider annotation on client on server-side

[marekkopecky]

According to the spec, it seems that ClientRequestFilter with @Provider annotation should be used with Client without registration. This behaviour currently doesn't work on Jersey, RESTEasy fix this on server side (see RESTEASY-2084, RESTEASY-2163)

I suggest to make clear in the spec, that this can work on server side, but not on standalone client application (outside of the container).

Example of server-side client usage:

@Provider
public class TestClientRequestFilter implements ClientRequestFilter {
    public void filter(ClientRequestContext clientRequestContext) {
        System.out.println("Hello from ClientRequestFilter");    
    }
}
@Path("/a")
public class Resource {
    @GET
    @Path("/a")
    public String a() {
        return "ok";
    }
    @Path("/b")
    @GET
    public String b() {
        Client client = ClientBuilder.newBuilder().build();
        final WebTarget target = client.target("http://127.0.0.1:8080/jaxrs-wf/a/a");
        final Response response = target.request().get();
        System.out.println(response.getStatus());
        System.out.println(response.readEntity(String.class));
        System.out.println();
        return "ok";
    }
}

The same situation is for ClientResponseFilter, MessageBodyReader, MessageBodyWriter, AsyncClientResponseProvider, ReaderInterceptor, WriterInterceptor, DynamicFeature

[spericas]

Yes, I agree this needs to be clarified. Generally speaking, support for @Provider requires a form of class scanning which is normally supported in server environments, and the mechanism was originally crafted to locate providers connected to the server API.

[mkarg]

#751 could be a vehicle to get this done

[ronsigal]

A related (I think) issue has come up in the MicroProfile REST Client group. MP REST Client defines a class, ClientHeadersFactory, which is, essentially, a provider, and the proposed 1.4 spec says that CDI and @context injection should work for ClientHeadersFactory's. The thing is, ClientHeadersFactory's are part of a MP REST Client environment, and the JAX-RS spec says that all but two @context injectable classes are only for the server side. So, if a MP REST Client is running in a JAX-RS resource, should it have access to the server side @context injectable classes? More generally, should a MP REST Client running in a JAX-RS resource have access to the server environemt? I think the answer depends on the answer to the same question for JAX-RS Clients.

[ronsigal]

Also related: #842.