java - jersey 2: How to create custom HTTP param binding

Question

I am trying to create a custom http param binding for my restful service. Please see the example below.

@POST
@Path("/user/{userId}/orders")
@Produces(MediaType.APPLICATION_JSON)
@Consumes(MediaType.APPLICATION_JSON)
public MyResult foo(@PathParam("userId") String someString, @UserAuthHeaderParam String authString){

}

You can see that there is a UserAuthHeaderParam annotation in the function signature. What I want to do is have a custom http param binding other than the standard javax.ws.rs.*Param .

I have try to implement org.glassfish.hk2.api.InjectionResolver which basically extract the value from http header:

public class ProtoInjectionResolver implements InjectionResolver<UserAuthHeaderParam>{
...
@Override
public Object resolve(Injectee injectee, ServiceHandle< ? > root)
{

    return "Hello World";
}
...

}

When I call the restful service, the server get below exceptions. It indicates that the framework fails to resolve the param in the function signature:

org.glassfish.hk2.api.UnsatisfiedDependencyException: There was no object available for injection at Injectee(requiredType=String,parent=MyResource,qualifiers={}),position=0,optional=false,self=false,unqualified=null,2136594195), 

java.lang.IllegalArgumentException: While attempting to resolve the dependencies of rs.server.MyResource errors were found

Please help. Any advise is appreciated. I do make a lot of search on google but fails to make it work. Jersey 2.*. How to replace InjectableProvider and AbstractHttpContextInjectable of Jersey 1.* might be the similar question.

-- UPDATES: I use AbstractBinder to bind my resolver to UserAuthHeaderParam:

public class MyApplication extends ResourceConfig
{

public MyApplication()
{
    register(new AbstractBinder()
    {
        @Override
        protected void configure()
        {
            // bindFactory(UrlStringFactory.class).to(String.class);
            bind(UrlStringInjectResolver.class).to(new TypeLiteral<InjectionResolver<UrlInject>>()
            {
            }).in(Singleton.class);
        }
    });
    packages("rs");

}

}

Thank you!

Answer 1

If all you want is to pass value directly from the header to the method you don't need to create custom annotations. Let's say you have a header Authorization, then you can easily access it by declaring your method like this:

@GET
public String authFromHeader(@HeaderParam("Authorization") String authorization) {
    return "Header Value: " + authorization + "
";
}

You can test it by calling curl, e.g.

$ curl --header "Authorization: 1234" http://localhost:8080/rest/resource
Header Value: 1234

Given that the answer to your question, how to create custom binding is as follows.

First you have to declare your annotation like this:

@java.lang.annotation.Target(PARAMETER)
@java.lang.annotation.Retention(RUNTIME)
@java.lang.annotation.Documented
public @interface UserAuthHeaderParam {
}

Having your annotation declared you have to define how it will be resolved. Declare the Value Factory Provider (this is where you'll have access to the header parameters - see my comment):

@Singleton
public class UserAuthHeaderParamValueFactoryProvider extends AbstractValueFactoryProvider {

    @Inject
    protected UserAuthHeaderParamValueFactoryProvider(MultivaluedParameterExtractorProvider mpep, ServiceLocator locator) {
        super(mpep, locator, Parameter.Source.UNKNOWN);
    }

    @Override
    protected Factory<?> createValueFactory(Parameter parameter) {
        Class<?> classType = parameter.getRawType();

        if (classType == null || (!classType.equals(String.class))) {
            return null;
        }

        return new AbstractHttpContextValueFactory<String>() {
            @Override
            protected String get(HttpContext httpContext) {
                // you can get the header value here
                return "testString";
            }
        };
    }
}

Now declare an injection resolver

public class UserAuthHeaderParamResolver extends ParamInjectionResolver<UserAuthHeaderParam> {
    public UserAuthHeaderParamResolver() {
        super(UserAuthHeaderParamValueFactoryProvider.class);
    }
}

and a Binder for your configuration

public class HeaderParamResolverBinder extends AbstractBinder {

    @Override
    protected void configure() {
        bind(UserAuthHeaderParamValueFactoryProvider.class)
                .to(ValueFactoryProvider.class)
                .in(Singleton.class);

        bind(UserAuthHeaderParamResolver.class)
                .to(new TypeLiteral<InjectionResolver<UserAuthHeaderParam>>() {})
                .in(Singleton.class);
    }
}

now the last thing, in your ResourceConfig add register(new HeaderParamResolverBinder()), like this

@ApplicationPath("rest")
public class MyApplication extends ResourceConfig {
    public MyApplication() {
        register(new HeaderParamResolverBinder());
        packages("your.packages");
    }
}

Given that, you should be now able to use the value as you wanted:

@GET
public String getResult(@UserAuthHeaderParam String param) {
    return "RESULT: " + param;
}

I hope this helps.