JSON malformed exception (Android Kotlin Retrofit PHP MySQL) - php

Question

I am developing an app with Kotlin-PHP-MySql.
I will be appreciated if someone has an idea why I get this exception "com.google.gson.stream.MalformedJsonException: Use JsonReader.setLenient(true) to accept malformed JSON at line 1 column 1 path" when I call createUser function.
I don't get an exception when I call getUser function with Same api.
I checked these two functions in postman. JSONs are formatted properly. Begins with
{ "key" : "value", "key1" : "value1", .... }
This is my api:
interface Api {
...
#POST("/api/v1/users/register_user.php")
suspend fun createUser(
#Body userDto: UserInfoPreviewDto
) : QueryResponse
#POST("/api/v1/users/get_user.php")
suspend fun getUser(
#Body jsonObject : JsonObject
) : UserDto
}
and my Retrofit instance:
Retrofit.Builder()
.baseUrl(BASE_URL)
.addConverterFactory(GsonConverterFactory.create())
.build()
.create(RamonApiUser::class.java)
and my server-side php code is
register_user.php file:
header("Access-Control-Allow-Origin: *");
header("Content-Type: application/json; charset=UTF-8");
header("Access-Control-Allow-Methods: POST");
header("Access-Control-Allow-Headers: Content-Type, Access-Control-Allow-
Headers, Authorization, X-Requested-With");
include_once("../../config/database.php");
include_once("../../classes/user.php");
$db = new Database();
$connection = $db->connect();
$user = new User($connection);
if($_SERVER['REQUEST_METHOD'] === "POST") {
$data = json_decode(file_get_contents("php://input"));
$user->username = $data->username;
$user->password = $data->password;
$user->fullname = $data->fullname;
$user->email = $data->email;
if($user->register()) {
http_response_code(200);
$result = array(
"status" => "200",
"message" => "saved"
);
echo json_encode($result);
}
else {
http_response_code(500);
echo json_encode(array(
"status" => "500",
"message" => "Error 500"
));
}
}
else {
http_response_code(503);
echo json_encode(array(
"status" => "503",
"message" => "Error 503"
));
}
this my get_user.php file:
header("Access-Control-Allow-Origin: *");
header("Content-Type: application/json; charset=UTF-8");
header("Access-Control-Allow-Methods: POST");
header("Access-Control-Allow-Headers: Content-Type, Access-Control-Allow-Headers,
Authorization, X-Requested-With");
include_once("../../config/database.php");
include_once("../../classes/user.php");
$db = new Database();
$connection = $db->connect();
$user = new User($connection);
if($_SERVER['REQUEST_METHOD'] === "POST") {
$param = json_decode(file_get_contents("php://input"));
if(!empty($param->id)) {
$user->id = $param->id;
$user_data = $user->getById();
if (!empty($user_data)) {
http_response_code(200);
$user_data['isPublicProfile'] = (bool)$user_data['isPublicProfile'];
$user_data['isLastOnlineVisible'] =
(bool)$user_data['isLastOnlineVisible'];
$user_data['isPhoneNumberVisible'] =
(bool)$user_data['isPhoneNumberVisible'];
echo json_encode($user_data);
}
}
}
else {
http_response_code(503);
echo json_encode(array(
"status" => "0",
"message" => "503 error"
));
}
getById() function in user.php :
public function getById() {
$sqlQuery = "SELECT * FROM ". $this->table_name ." WHERE id = ? LIMIT 0,1";
$obj = $this->conn->prepare($sqlQuery);
$obj->bind_param("i", $this->id);
$obj->execute();
$data = $obj->get_result();
return $data->fetch_assoc();
}
I have QueryResponse data class in the client-side with the fields status and message. user->register() returns true or false . I think the problem is with my json_encode method. I also tried this:
I created a QueryReponse php class with fields status and message and encode this object like this:
$query_response = new QueryResponse();
$query_response->status = "200";
$query_response->message = "registration successful";
$echo json_encode($query_response);
it didn't help either.

Answer 1

I created another file called get_query_response.php. Just to make sure that my QueryResponse classes are OK and doesn't throw exceptions.
get_query_response.php:
....
include_once("../../config/database.php");
include_once("../../classes/query_response.php");
$db = new Database();
$connection = $db->connect();
$query_response = new QueryResponse($connection);
if($_SERVER['REQUEST_METHOD'] === "POST") {
$query_response->id = 1;
$query_response_data = $query_response->getById();
// I fetch query_response_data from mysql
if (!empty($query_response_data)) {
http_response_code(200);
$result = array(
"status" => "500",
"message" => "save successfully"
);
echo json_encode($result); // doesn't throw exception.
works fine
//echo json_encode($query_response_data);
//when i use this line, it doesn't throw exception
//either. works fine
}
}
I call this file get_query_response.php from my api like this:
interface MyApi {
...
#POST("/api/v1/users/get_query_response.php")
suspend fun getQueryResponse() : QueryResponse
...
}
No errors, no exceptions. Both echo json_encode($result) and echo json_encode($query_response_data) works fine.
The only difference between two register_user.php and get_query_response.php files is this line:
$data = json_decode(file_get_contents("php://input"));
I don't get the reason why these two files behave differently. They are almost identical. Why does not this code work in register_user.php?
$result = array(
"status" => "200",
"message" => "saved successfully"
);
echo json_encode($result);
I finally solved the problem. It was my data class UserInfo. One field of the class was being assigned null during instantiation. Api is sending a class which two properties of that class has null values. The problem is solved by assigning values to those properties.