Retrofit 1.9 keeps calling failure and returns null body

Question

I am trying to communicate with my php web service (Google App Engine), but it keeps responding with body as null and also triggering the failure() method of Retrofit (callback).

I get the following error message in failure(), when debugging it:

retrofit.RetrofitError: com.google.gson.JsonSyntaxException: java.lang.IllegalStateException: Expected BEGIN_OBJECT but was STRING at line 1 column 1 path $

First here is the code where I trigger the request to my web service:

 WebServiceManager.getInstance().registerRequest(email, password, username, firstname, lastname, new Callback<RegisterResponse>() {
                        @Override
                        public void success(RegisterResponse registerResponse, Response response) {
                            Toast.makeText(context, registerResponse.getToken() + "", Toast.LENGTH_LONG).show();
                        }

                        @Override
                        public void failure(RetrofitError error) {
                            Toast.makeText(context,"error ", Toast.LENGTH_LONG).show();
                        }
                    });

And here is my WebServiceManager class for managing the requests and responses: http://pastebin.com/Q8bzqQ0M

And the model classes for the requests and responses: http://pastebin.com/aB98Yiua

This is how my json request looks like:

{
    data{
        "email": "regd@rgersf.dk",
        "firstname": "regdrgersf",
        "lastname": "regdrgersf",
        "password": "hejhejhej",
        "username": "regdrgersf"
    }
}

I also think it is relevant to include the part where I receive the request on my web service:

<?php
require '../functions/db.php';

$data = getJsonRequest();

$email      = $data['data']['email'];
$password   = $data['data']['password'];
$username   = $data['data']['username'];
$firstname  = $data['data']['firstname'];
$lastname   = $data['data']['lastname'];
$facebookID = $data['data']['facebookID'];

$dbClass = new DBClass();
$result = $dbClass->register($email, $password, $username, $firstname, $lastname, $facebookID);

$response = array();
if ($result == $dbClass->error_input || $result == $dbClass->error_email_exists || $result == $dbClass->error_unknown || $result == $dbClass->error_db_connection) {
    $response['status'] = false;
    $response['error'] = $result;

} else {
    $response['status'] = true;
    $response['token'] = $result;
}

sendJsonResponse($response);

?>

And the function "sendJsonResponse($response)" for sending the response:

function sendJsonResponse($response) {
    header('HTTP/1.1 200 OK');
    header('Content-type: application/json');

    echo json_encode($response);
}

I can't figure out if the problem is somewhere in my Java (Android) code and retrofit or if I'm doing something wrong on the webserver.

Answer 1

I found a way to fix it myself, so I think I should post my solution here so that it might help others.. even though I am not sure why my first solution didn't work. By removing the annotation @FormUrlEncoded and changing @Field('data') to @Body, it actually worked. Så the interface looks like this now.

private interface webServiceInterface {
    @POST(WebServiceManager.REQUEST_REGISTER)
    void register(@Body RegisterRequest registerRequest, Callback<RegisterResponse> response);
}

Anyways, I really appreciate all the help I got from people here.