Is there a way to add query parameter to every request with Retrofit 2?

Question

I need to add a query parameter to every request made by Retrofit 2.0.0-beta2 library. I found this solution for Retrofit 1.9, but how to add RequestInterceptor in newest library version?

My interface:

@GET("user/{id}")
Call<User> getUser(@Path("id")long id);

@GET("users/")
Call<List<User>> getUser();

Client:

Retrofit retrofit = new Retrofit.Builder()
                    .baseUrl(BASE_URL)
                    .addConverterFactory(GsonConverterFactory.create())
                    .client(CLIENT)  // custom OkHTTP Client
                    .build();
service = retrofit.create(userService.class);

Answer 1

For the sake of completeness, here is the full code you need to add a parameter to every Retrofit 2.x request using a OkHttp-Interceptor:

OkHttpClient client = new OkHttpClient();

client.interceptors().add(new Interceptor() {
    @Override
    public Response intercept(Chain chain) throws IOException {
        Request request = chain.request();
        HttpUrl url = request.url().newBuilder().addQueryParameter("name","value").build();
        request = request.newBuilder().url(url).build();
        return chain.proceed(request);
    }
});

Retrofit retrofit = new Retrofit.Builder()
        .baseUrl("...")
        .client(client)
        .build();