Add Header Parameter in Retrofit

Question

I'm trying to call an API which requires me to pass in an API key.

My Service call using HttpURLConnection is working perfectly.

url = new URL("https://developers.zomato.com/api/v2.1/search?entity_id=3&entity_type=city&q=" + params[0]); urlConnection = (HttpURLConnection) url.openConnection();  urlConnection.setRequestProperty("user-key","9900a9720d31dfd5fdb4352700c");  if (urlConnection.getResponseCode() != 200) {     Toast.makeText(con, "url connection response not 200 | " + urlConnection.getResponseCode(), Toast.LENGTH_SHORT).show();     Log.d("jamian", "url connection response not 200 | " + urlConnection.getResponseCode());     throw new RuntimeException("Failed : HTTP error code : " + urlConnection.getResponseCode()); } 

However, I'm not sure how this works with Retrofit as my call in going into Failure at all times. Here's the code I'm using for the same service call

@GET("search") Call<String> getRestaurantsBySearch(@Query("entity_id") String entity_id, @Query("entity_type") String entity_type, @Query("q") String query,@Header("Accept") String accept, @Header("user-key") String userkey); 

and I'm using this to call it

Call<String> call = endpoint.getRestaurantsBySearch("3","city","mumbai","application/json","9900a9720d31dfd5fdb4352700c"); 

All these calls are going into the OnFailure Method in RetroFit. If I send it without the HeaderParameters it goes into Success with a 403 because I obviously need to pass the api key somewhere but I cant figure out how.

@GET("search") Call<String> getRestaurantsBySearch(@Query("entity_id") String entity_id, @Query("entity_type") String entity_type, @Query("q") String query); 

The error I'm getting in OnFailure is

java.lang.IllegalStateException: Expected a string but was BEGIN_OBJECT at line 1 column 2 path $ 

Answer 1

Try this type header for Retrofit 1.9 and 2.0. For the JSON content type.

@Headers({"Accept: application/json"}) @POST("user/classes") Call<playlist> addToPlaylist(@Body PlaylistParm parm); 

You can add many more headers, i.e,

@Headers({         "Accept: application/json",         "User-Agent: Your-App-Name",         "Cache-Control: max-age=640000"     }) 

Dynamically add to headers:

@POST("user/classes") Call<ResponseModel> addToPlaylist(@Header("Content-Type") String content_type, @Body RequestModel req); 

Call your method, i.e.,

mAPI.addToPlayList("application/json", playListParam); 

Or

Want to pass every time, then create an HttpClient object with the HTTP Interceptor:

OkHttpClient httpClient = new OkHttpClient();         httpClient.networkInterceptors().add(new Interceptor() {             @Override             public com.squareup.okhttp.Response intercept(Chain chain) throws IOException {                 Request.Builder requestBuilder = chain.request().newBuilder();                 requestBuilder.header("Content-Type", "application/json");                 return chain.proceed(requestBuilder.build());             }         }); 

Then add to a Retrofit object

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

If you are using Kotlin, remove the { }. Else it will not work.

Answer 2

You can use the below

 @Headers("user-key: 9900a9720d31dfd5fdb4352700c")  @GET("api/v2.1/search")  Call<String> getRestaurantsBySearch(@Query("entity_id") String entity_id, @Query("entity_type") String entity_type, @Query("q") String query); 

and

 Call<String> call = endpoint.getRestaurantsBySearch("3","city","cafes"); 

The above is based in the zomato api which is documented at

https://developers.zomato.com/documentation#!/restaurant/search

Thing to note is the end point change api/v2.1/search and the Header @Headers("user-key: 9900a9720d31dfd5fdb4352700c").

Also check your base url .baseUrl("https://developers.zomato.com/")

Also i tried the above with a api key i generated and it works and my query was cafes as suggested the zomato documentation.

Note : I hope you have the below

 .addConverterFactory(ScalarsConverterFactory.create()) // for string conversion  .build(); 

and the below in build.gradle file

compile group: 'com.squareup.retrofit2', name: 'converter-scalars', version: '2.2.0' 

Edit:

You can also pass header with dynamic value as below

@GET("api/v2.1/search") Call<String> getRestaurantsBySearch(@Query("entity_id") String entity_id, @Query("entity_type") String entity_type, @Query("q") String query,@Header("user-key") String userkey); 

And

Call<String> call = endpoint.getRestaurantsBySearch("3","city","cafes","9900a9720d31dfd5fdb4352700c");