title: Retrofit2: Modifying request body in OkHttp Interceptor
body: <p>I am using Retrofit 2 (2.0.0-beta3) with OkHttp client in Android application and so far everything going great. But currently I am facing issue with OkHttp Interceptor. The server I am communicating with is taking access token in body of request, so when I intercept the request to add auth token or in authenticate method of Authenticator when I need to add updated auth token, I need to modify body of request for this purpose. But it looks like I can only add data in headers but not in the body of ongoing request. The code I have written so far is as follows:</p>
  
  <pre><code>client.interceptors().add(new Interceptor() {
              @Override
              public Response intercept(Chain chain) throws IOException {
                  Request request = chain.request();
                  if (UserPreferences.ACCESS_TOKEN != null) {
                      // need to add this access token in request body as encoded form field instead of header
                      request = request.newBuilder()
                              .header("access_token", UserPreferences.ACCESS_TOKEN))
                              .method(request.method(), request.body())
                              .build();
                  }
                  Response response = chain.proceed(request);
                  return response;
              }
          });
  </code></pre>
  
  <p>Can anyone point me to the right direction as how to modify request body to add my access token (first time or updated after token refresh)? Any pointer to right direction would be appreciated. </p>