Prevent retrofit from encoding my http request body

Question

I'm trying to pass a string of the format below as the body of a http post request.

param1=PARAM1&param2=PARAM2&param3=PARAM3

But retrofit encodes my body so that = becomes \u003d and & becomes \u0026. And I end up with a string which actually looks like this:

param1\u003dPARAM1\u0026param2\u003dPARAM2\u0026param3\u003dPARAM3

How can I prevent that?

My retrofit rest api is defined as follows.

public interface RestAPI {
    @POST("/oauth/token")
    public void getAccessToken(@Body String requestBody, Callback<Response> response);
}

Answer 1

If you have a serialized class (like a HashMap) in the request body and you want to prevent encoding that (like in vezikon's and my problem), you can create a custom Gson with disabled escaping using:

Gson gson = new GsonBuilder().disableHtmlEscaping().create();

Pass this converter to your rest adapter:

yourRestAdapter  = new RestAdapter.Builder()
    .setEndpoint(.....)
    .setClient(.....)
    .setConverter(new GsonConverter(gson))
    .build();

This way the "=" characters in the post body stay intact while submitting.

Answer 2

To answer the question directly, you can use TypedString as the method parameter type. The reason the value is being changed is because Retrofit is handing the String to Gson in order to encode as JSON. Using TypedString or any TypedOutput subclass will prevent this behavior, basically telling Retrofit you will handle creating the direct request body yourself.

However, that format of payload is called form URL encoding. Retrofit has native support for it. Your method declaration should actually look like this:

@FormUrlEncoded
@POST("/oauth/token")
void getAccessToken(
    @Field("param1") String param1,
    @Field("param2") String param2,
    @Field("param3") String param3,
    Callback<Response> callback);