How to define a Header to all request using Retrofit?

Question

I'm looking for a solution to define a unique Header to use in all requests. Today I use @Header to each request did pass like parameter but I want define only header that works in all requests without to need pass like a parameter, for example fixing this Header on my requests @GET and @POST

Today I use this. Note that each request @GET I need define Header as parameter.

//interface @GET("/json.php") void getUsuarioLogin(                            @Header("Authorization") String token,                         @QueryMap Map<String, String> params,                         Callback<JsonElement> response                     );  //interface @GET("/json.php") void addUsuario(                             @Header("Authorization") String token,                         @QueryMap Map<String, String> params,                         Callback<JsonElement> response                     );   //using public void getUsuarioLogin(){         Map<String, String> params = new HashMap<String, String>();                  params.put("email", "[email protected]");         params.put("senha", ConvertStringToMD5.getMD5("mypassword"));                     RestAdapter adapter = new RestAdapter.Builder()                                 .setLogLevel(RestAdapter.LogLevel.FULL)                                 .setEndpoint(WebServiceURL.getBaseWebServiceURL())                                                               .build();          UsuarioListener listener = adapter.create(UsuarioListener.class);         listener.getUsuarioLogin(                                       //header                                         "Basic " + BasicAuthenticationRest.getBasicAuthentication(),                                       params,                                        new Callback<JsonElement>() {                      @Override             public void success(JsonElement arg0, Response arg1) {                 Log.i("Usuario:", arg0.toString() + "");                             }              @Override             public void failure(RetrofitError arg0) {                 Log.e("ERROR:", arg0.getLocalizedMessage());              }         });       }      //using     public void addUsuario(){             Map<String, String> params = new HashMap<String, String>();             params.put("name", "Fernando");             params.put("lastName", "Paiva");              RestAdapter adapter = new RestAdapter.Builder()                                     .setLogLevel(RestAdapter.LogLevel.FULL)                                     .setEndpoint(WebServiceURL.getBaseWebServiceURL())                                                                   .build();              UsuarioListener listener = adapter.create(UsuarioListener.class);             listener.addUsuario(                                           //header                                             "Basic " + BasicAuthenticationRest.getBasicAuthentication(),                                           params,                                            new Callback<JsonElement>() {                          @Override                 public void success(JsonElement arg0, Response arg1) {                     Log.i("Usuario:", arg0.toString() + "");                                 }                  @Override                 public void failure(RetrofitError arg0) {                     Log.e("ERROR:", arg0.getLocalizedMessage());                  }             });           } 

Answer 1

Official document:

Headers that need to be added to every request can be specified using a RequestInterceptor. The following code creates a RequestInterceptor that will add a User-Agent header to every request.

RequestInterceptor requestInterceptor = new RequestInterceptor() {   @Override   public void intercept(RequestFacade request) {     request.addHeader("User-Agent", "Retrofit-Sample-App");   } };  RestAdapter restAdapter = new RestAdapter.Builder() .setEndpoint("https://api.github.com") .setRequestInterceptor(requestInterceptor) .build(); 

Answer 2

In Retrofit 2, you need to intercept the request on the network layer provided by OkHttp

OkHttpClient.Builder httpClient = new OkHttpClient.Builder();   httpClient.addInterceptor(new Interceptor() {   @Override public Response intercept(Interceptor.Chain chain) throws IOException {     Request original = chain.request();      Request request = original.newBuilder()         .header("User-Agent", "Your-App-Name")         .header("Accept", "application/vnd.yourapi.v1.full+json")         .method(original.method(), original.body())         .build();      return chain.proceed(request);    } }  OkHttpClient client = httpClient.build();   Retrofit retrofit = new Retrofit.Builder()       .baseUrl(API_BASE_URL)     .addConverterFactory(GsonConverterFactory.create())     .client(client)     .build(); 

Check this, it explains the differences very well.