No injection source found for a parameter

Hello,

I am having troubles adding Basic Authentication to my Dropwizard application. I am using DW 0.8.1 I have followed this artciles http://java.dzone.com/articles/getting-started-dropwizard-0 but I keep getting the following

WARN  [2015-06-17 08:55:10,030] /: unavailable
! org.glassfish.jersey.server.model.ModelValidationException: Validation of the application resource model has failed during application initialization.
! [[FATAL] No injection source found for a parameter of type

Initially I thought that the issue was related to https://github.com/dropwizard/dropwizard/issues/783 but my configuration follows the ones in the doc:

   @PATCH
   @Path("/books/{id}")
   @Consumes("application/json")
   public void updateTitle(
           @Auth User user,
           @PathParam("id") String bookId, BookBean bookBean) {

   }

the application configuration

 environment.jersey().register(AuthFactory.binder(
              new BasicAuthFactory<>(
                      new UserBasicAuthenticator(configuration.getAuthenticationConfiguration().getUser(),
                              configuration.getAuthenticationConfiguration().getPassword()),
                      "SECURITY REALM",
                      User.class)));

and UserBasicAuthenticator is

...
 public Optional<User> authenticate(BasicCredentials credentials)
            throws AuthenticationException {
        if (password.equals(credentials.getPassword())
                && user.equals(credentials.getUsername())) {
            return Optional.of(new User(credentials.getUsername()));
        } else {
            return Optional.absent();
        }
    }
...

[psamsotha]

For any future readers, here is the reason for the error.

When Jersey starts up, it builds a model of all the resources. In the model includes all the parameters. The Jersey validates the model. It does this to benefit us, by making sure that the all the models can be processed correctly during a request. Part of the validation process consists of validating the parameters. There are some rules that guide what parameters we can have. For instance we can only have one entity body parameters (excluding things like @FormParam and @FormDataParam). The entity parameter is generally the parameter with no annotation.

The way the validation works for parameters is that it for each parameter, Jersey traverses all the ValueFactoryProviders and it passes the Parameter (which is a model of the actual parameter) to the ValueFactoryProvider, and expects a Factory to be returned. If a Factory is not returned from one ValueFactoryProvider, then it goes on to the next until either a Factory is returned, or all the ValueFactoryProviders have been checked and no Factory has been returned by any of them. In which case Jersey throws a ModelValidationException, as there is no ValueFactoryProvider to handle that parameter. Things like @PathParam, @QueryParam, @FormParam and other framework parameter annotations have their own ValueFactoryProviders automatically installed.

That being said when traversing the parameters, Jersey give one pass for a single entity parameter. So for the error to occur in an example such as

@POST
public Response addOrcamento(@Auth User user, OrcamentoRepresentation orc) {
...
}

one of those parameter passes are failing. The OrcamentoRepresentation parameter will be given the entity parameter pass, but the User fails as there is no ValueFactoryProvider that returns a Factory for that parameter.

But the thing is, the AuthValueFactoryProvider is the component that provides the value for the @Auth User parameter. You can see here in the source

https://github.com/dropwizard/dropwizard/blob/2565a66fbb62e28c8e7ac2754be14e594fd1b445/dropwizard-auth/src/main/java/io/dropwizard/auth/AuthValueFactoryProvider.java#L53-L59

where it actually returns the Factory. The only thing that could cause it to fail is if the following condition were to fail

!principalClass.equals(parameter.getRawType())

But it shouldn’t fail, as the principalClass is obtained through our passing the class to the AuthValueFactoryProvider.Binder<>(User.class);. As long as the principalClass and the actual parameter class are the same, the condition should pass.

@ivanjeukens I’ve tested with your exact configuration with 0.9.2, and it works fine. Maybe a clean and build. Or maybe the problem is somewhere else. I don’t know. But I hope I gave you some idea of what the problem is.

[mdeanda]

I ran into a similar issue simply importing the wrong annotation:

import javax.websocket.server.PathParam; import javax.ws.rs.PathParam;

It may not be the case for you but I lost a few days on it.