My Rest API

<?php
require 'config.php';
require 'Slim/Slim.php';

\Slim\Slim::registerAutoloader();
$app = new \Slim\Slim();

$app->post('/login','login'); /* User login */
$app->post('/signup','signup'); /* User Signup  */
$app->get('/getFeed','getFeed'); /* User Feeds  */
$app->post('/feed','feed'); /* User Feeds  */
$app->post('/feedUpdate','feedUpdate'); /* User Feeds  */
$app->post('/feedDelete','feedDelete'); /* User Feeds  */
$app->post('/getImages', 'getImages');


$app->run();

/************************* USER LOGIN *************************************/
/* ### User login ### */
function login() {

    $request = \Slim\Slim::getInstance()->request();
    $data = json_decode($request->getBody());

    try {

        $db = getDB();
        $userData ='';
        $sql = "SELECT user_id, name, email, username FROM users WHERE (username=:username or email=:username) and password=:password ";
        $stmt = $db->prepare($sql);
        $stmt->bindParam("username", $data->username, PDO::PARAM_STR);
        $password=hash('sha256',$data->password);
        $stmt->bindParam("password", $password, PDO::PARAM_STR);
        $stmt->execute();
        $mainCount=$stmt->rowCount();
        $userData = $stmt->fetch(PDO::FETCH_OBJ);

        if(!empty($userData))
        {
            $user_id=$userData->user_id;
            $userData->token = apiToken($user_id);
        }

        $db = null;
         if($userData){
               $userData = json_encode($userData);
                echo '{"userData": ' .$userData . '}';
            } else {
               echo '{"error":{"text":"Bad request wrong username and password"}}';
            }


    }
    catch(PDOException $e) {
        echo '{"error":{"text":'. $e->getMessage() .'}}';
    }
}


/* ### User registration ### */
function signup() {
    $request = \Slim\Slim::getInstance()->request();
    $data = json_decode($request->getBody());
    $email=$data->email;
    $name=$data->name;
    $username=$data->username;
    $password=$data->password;

    try {

        $username_check = preg_match('~^[A-Za-z0-9_]{3,20}$~i', $username);
        $email_check = preg_match('~^[a-zA-Z0-9._-]+@[a-zA-Z0-9._-]+\.([a-zA-Z]{2,4})$~i', $email);
        $password_check = preg_match('~^[A-Za-z0-9!@#$%^&*()_]{6,20}$~i', $password);

       // echo $email_check.'<br/>'.$email;

        if (strlen(trim($username))>0 && strlen(trim($password))>0 && strlen(trim($email))>0 && $email_check>0 && $username_check>0 && $password_check>0)
        {
            //echo 'here';
            $db = getDB();
            $userData = '';
            $sql = "SELECT user_id FROM users WHERE username=:username or email=:email";
            $stmt = $db->prepare($sql);
            $stmt->bindParam("username", $username,PDO::PARAM_STR);
            $stmt->bindParam("email", $email,PDO::PARAM_STR);
            $stmt->execute();
            $mainCount=$stmt->rowCount();
            $created=time();
            if($mainCount==0)
            {

                /*Inserting user values*/
                $sql1="INSERT INTO users(username,password,email,name)VALUES(:username,:password,:email,:name)";
                $stmt1 = $db->prepare($sql1);
                $stmt1->bindParam("username", $username,PDO::PARAM_STR);
                $password=hash('sha256',$data->password);
                $stmt1->bindParam("password", $password,PDO::PARAM_STR);
                $stmt1->bindParam("email", $email,PDO::PARAM_STR);
                $stmt1->bindParam("name", $name,PDO::PARAM_STR);
                $stmt1->execute();

                $userData=internalUserDetails($email);

            }

            $db = null;


            if($userData){
               $userData = json_encode($userData);
                echo '{"userData": ' .$userData . '}';
            } else {
               echo '{"error":{"text":"Enter valid data"}}';
            }


        }
        else{
            echo '{"error":{"text":"Enter valid data"}}';
        }
    }
    catch(PDOException $e) {
        echo '{"error":{"text":'. $e->getMessage() .'}}';
    }
}
?>