unexpected 'A' Postman php api with JSON Response - php

Question

Recently I try to create an API with PHP. all thing goes alright till suddenly I face unexpected 'a' error when trying to parse a JSON from the request throw Postman. I found something related to my issue but there is no solution in my case here : link
I send
{
"teacher_code":"sas"
}
JSON to teachers.php file to assign a student to the teacher
here is the teacher.php file content :
require_once ("classes/Rest.php");
require_once ("classes/api.php");
$api = new Api();
if($api->getHttpmethod() === 'POST'){
$api->validateParameter('teacher_code' ,$teacher_code = $api->getParam('teacher_code') , STRING , true);
$api->checkUserAccessablity();
$api->teacherCodeinRange($teacher_code);
$query = "INSERT INTO `group_users` (`user_id`,`group_id` )
VALUES (:user_id , (SELECT group_id FROM `groups` WHERE group_name = 'all' AND user_id =
(SELECT user_id FROM `teachers` WHERE t_code = :teacher_code)) )";
$keyValue = [
"user_id" => $api->getUserid() ,
"teacher_code" => $teacher_code
];
$result = $api->queryExecute($query , $keyValue );
$api->returnResponse(SUCCESS , SUCCESS_MESSAGE);
}
and api.php file :
require_once ("dbConnect.php");
require_once ("JWT.php");
class Api extends Rest
{
public $dbConn;
private $userId;
public function __construct()
{
parent::__construct();
$db = new dbConnect();
$this->dbConn = $db->connect();
}
public function setUserid($id){
$this->userId = $id;
}
public function getUserid(){
return $this->userId;
}
public function checkUserAccessablity(){
$payload = $this->deCodetoken();
$this->setUserid($payload->user_id);
$this->validateUser();
}
public function validateUser(){
$query = "SELECT * FROM `users` WHERE user_id = :id";
$keyValue = [
"id" => $this->getUserid()
];
$result = $this->queryExecute($query , $keyValue,true );
if(!$result){
$this->throwError(SYSTEM_ERROR , SYSTEM_ERROR_MESSAGE );
}
if(!is_array($result)){
$this->throwError(USER_NOT_FOUND_CODE , USER_NOT_FOUND_MESSAGE . $this->getUserid());
}
//TODO CHECK USER ACTIVE
return true;
}
public function teacherCodeinRange($tCode){
$query = "SELECT * FROM `teachers` INNER JOIN `licenses` ON (licenses.user_id = teachers.user_id)
WHERE teachers.t_code = :tcode LIMIT 1";
$keyValue = [
"tcode" => $tCode
];
$this->queryExecute($query , $keyValue,true );
return true;
}
public function teacherCodeinStudentrange($teacherID){
//TODO SELECT TEACHER STUDENT RANGE
$query = "SELECT DISTICT user_id FROM `teachers` INNER JOIN `groups` ON (groups.user_id = teachers.user_id)
INNER JOIN `group_users` ON (group_users.group_id = groups.group_id)
WHERE teachers.user_id = :teacherID AND groups.group_name = 'all' AND group_users.user_id = :userID ";
$keyValue = [
"userID" => $this->getUserid(),
"teacherID" => $teacherID,
];
$result = $this->queryExecute($query , $keyValue,true );
if(!is_array($result)){
$this->throwError(TEACHER_NOT_FOUND , TEACHER_NOT_FOUND_MESSAGE);
}
return true;
}
public function getHttpmethod(){
return $this->HttpMethod;
}
public function getParam($key){
return $this->arrayFinddeep($this->data , $key);
}
public function queryExecute($query , $keyArray , $isSelect = false){
$queryExec = $this->dbConn->prepare($query);
if(is_array($keyArray) || !empty($keyArray)) {
foreach ($keyArray as $key => &$value) {
$queryExec->bindParam(':' . $key, $value);
}
}
if($isSelect) {
$queryExec->execute();
$result = $queryExec->fetch(PDO::FETCH_ASSOC);
}else {
$result = $queryExec->execute();
}
return $result;
}
public function getLastuserId(){
return $this->dbConn->lastInsertId();
}
public function generateToken($payload , $secretKey){
try{
return \Firebase\JWT\JWT::encode($payload , $secretKey);
}catch (Exception $exception){
$this->throwError(JWT_PROCESSING_ERROR , $exception->getMessage());
}
}
public function deCodetoken(){
try{
$token = $this->getBearerToken();
$payload = \Firebase\JWT\JWT::decode($token , SECURITY_KEY , ['HS256']);
return $payload;
}catch (Exception $exception){
$this->throwError(ACCESS_TOKEN_ERROR , $exception->getMessage());
}
}
}
and the last class is Rest.php :
require_once ("Constans.php");
class Rest
{
protected $HttpMethod;
protected $request;
protected $data;
public function __construct(){
$this->HttpMethod = $_SERVER['REQUEST_METHOD'];
if($this->checkValidhttpMethod()) {
try{
$handler = fopen('php://input', 'r');
$this->request = stream_get_contents($handler);
}catch (Exception $exception){
//TODO HANDLE EXEPTION
}
$this->validateRequest();
}
}
public function checkValidhttpMethod(){
if(empty($this->HttpMethod) or !in_array($this->HttpMethod,ACCEPTABLE_HTTP_METHOD)){
$this->throwError(NOT_VALID_HTTP_METHOD,NOT_VALID_HTTP_METHOD_Message);
}
return true;
}
public function setJsonheader(){
header("content-type: application/json");
}
public function validateRequest(){
if($_SERVER['CONTENT_TYPE'] !== 'application/json'){
$this->throwError(REQUEST_CONTENT_NOT_VALID , REQUEST_CONTENT_NOT_VALID_MESSAGE);
}
try{
$this->data = json_decode($this->request , true);
}catch (Exception $exception){
//TODO HANDLE EXEPTION
}
}
public function processAPI(){
}
public function throwError($code , $message){
$this->setJsonheader();
echo json_encode(['error' => ['status' => $code , 'message' => $message]]);
exit;
}
public function returnResponse($code , $data){
$this->setJsonheader();
echo json_encode(['response' => ['status' => $code , 'result' => $data ]]);
exit;
}
//TODO SQL injection Validate
public function validateParameter($fieldName , $value , $dataType , $required = true){
if($required && empty($value)){
$this->throwError(PARAMETR_REQUIRED,PARAMETR_REQUIRED_MESSAGE . $fieldName);
}
//TODO SQL injection
//TODO CHECK The All Data Type
switch ($dataType){
case BOOLEAN :
if(!is_bool($value)){
$this->throwError(PARAMETR_DATA_TYPE_NOT_VALID , PARAMETR_DATA_TYPE_NOT_VALID_MESSAGE . $fieldName);
}
break;
case INTEGER :
if(!is_numeric($value)){
$this->throwError(PARAMETR_DATA_TYPE_NOT_VALID , PARAMETR_DATA_TYPE_NOT_VALID_MESSAGE . $fieldName);
}
break;
case STRING :
if(!is_string($value)){
$this->throwError(PARAMETR_DATA_TYPE_NOT_VALID , PARAMETR_DATA_TYPE_NOT_VALID_MESSAGE . $fieldName);
}
break;
case DONT_CARE :
break;
default:
break;
}
return $value;
}
public function arrayFinddeep($array, $search)
{
foreach($array as $key => $value) {
if (is_array($value)) {
$sub = $this->arrayFinddeep($value, $search);
if (count($sub)) {
return $sub;
}
} elseif ($key === $search) {
return $value;
}
}
return array();
}
/**
* Get hearder Authorization
* */
function getAuthorizationHeader(){
$headers = null;
if (isset($_SERVER['Authorization'])) {
$headers = trim($_SERVER["Authorization"]);
}
else if (isset($_SERVER['HTTP_AUTHORIZATION'])) { //Nginx or fast CGI
$headers = trim($_SERVER["HTTP_AUTHORIZATION"]);
} elseif (function_exists('apache_request_headers')) {
$requestHeaders = apache_request_headers();
// Server-side fix for bug in old Android versions (a nice side-effect of this fix means we don't care about capitalization for Authorization)
$requestHeaders = array_combine(array_map('ucwords', array_keys($requestHeaders)), array_values($requestHeaders));
//print_r($requestHeaders);
if (isset($requestHeaders['Authorization'])) {
$headers = trim($requestHeaders['Authorization']);
}
}
return $headers;
}
/**
* get access token from header
* */
function getBearerToken() {
$headers = $this->getAuthorizationHeader();
// HEADER: Get the access token from the header
if (!empty($headers)) {
if (preg_match('/Bearer\s(\S+)/', $headers, $matches)) {
return $matches[1];
}
}
$this->throwError(AUTHORIZATION_HEADER_NOT_FOUND , AUTHORIZATION_HEADER_NOT_FOUND_MESSAGE);
}
}
all queries go along queryExecute function in api.php class and recently I got that the bindParam function is not going to work fine too.
I really don't have any idea where the problem is, as In the reference said its somehow related to DB queries result. I try to use mysqli also but it did not work.
any help will be appreciated :-)