OkHttp POST Does Not Seem to Send Request Body

Question

I am trying to use RetroFit2 and OkHttp3 to do a POST method on a PHP script. I have been doing GET methods perfectly fine, but I have been having problems with posting.

I have an HttpLoggingInterceptor set up with my OkHttpClient, and it logs the request body perfectly. But my PHP script was not receiving the data, so I tried just outputting the $_POST data as soon as I got it, but it is an empty string. I cannot tell if there is something wrong on the Android side, the server side, or both.

My RetroFit object and OkHttpClient are set up like so:

HttpLoggingInterceptor interceptor = new HttpLoggingInterceptor();
interceptor.setLevel(HttpLoggingInterceptor.Level.BODY);

OkHttpClient client = new OkHttpClient.Builder()
        .cookieJar(RestCookieJar.getInstance())
        .addInterceptor(interceptor)
        .build();

Gson gson = new GsonBuilder()
        .setFieldNamingPolicy(FieldNamingPolicy.LOWER_CASE_WITH_UNDERSCORES)
        .registerTypeAdapter(Instant.class, new InstantAdapter())
        .registerTypeAdapter(LatLng.class, new LatLngAdapter())
        .registerTypeAdapter(Uri.class, new UriAdapter())
        .create();

Retrofit retrofit = new Retrofit.Builder()
        .addCallAdapterFactory(RxJavaCallAdapterFactory.create())
        .addConverterFactory(GsonConverterFactory.create(gson))
        .client(client)
        .baseUrl(BASE_URL)
        .build();

RestService service = retrofit.create(RestService.class);

Then my RestService interface is set up like this:

public interface RestService {

    @GET("api/index.php")
    Call<List<Session>> getSessions();

    @POST("api/index.php")
    Call<ResponseBody> postSession(@Body Session session);
}

As I mentioned, this all seems to work, but when I call:

<?php

    if($_SERVER['REQUEST_METHOD'] === 'POST') {
        print_r($_POST);
    }

I get an empty set of parenthesis.

score 4 · Accepted Answer · edited May 23 '17 at 11:59

I found my answer here: php $_POST array empty upon form submission. Retrofit automatically sets the Content-Type to "application/json; charset=UTF-8", which in PHP versions 5.0 - 5.19, there is a bug causing the request body to not be parsed into the $_POST variable. The server I am using is running PHP 5.10 (which I have no control over).

The workaround for this bug is to parse the JSON data yourself from the raw request body:

if($_SERVER['CONTENT_TYPE'] === 'application/json; charset=UTF-8') {
    $_POST = json_decode(file_get_contents('php://input'));
}

OkHttp POST Does Not Seem to Send Request Body

1 Answers1