Why i get no response on cUrl with class?

Question

Without class, just plain code my method is working and getting "SUCCESS" response_status, but when i put it in a class i get nothing.

All code:

class THBS_API
{
    private const call_url = "https://xxxxxxxxxxxx.xxx/endsoftware.php";
    private $base_url;
    private $fields;
    private $fields_string;

    public static function getUsers()
    {
        $base_url = $_SERVER['SERVER_NAME'];
        $fields_string = '';

        $fields = array(
        'API_USER' => urlencode('xxxxxx@xxxxxx.xxx'),
        'API_PASS' => urlencode('xxxxxxxxx'),
        'CMD' => urlencode('getUserCount'),
        'FROM' => urlencode($base_url));

        //url-ify the data for the POST
        foreach($fields as $key=>$value) { $fields_string .= $key.'='.$value.'&'; }
        rtrim($fields_string, '&');

        //open connection
        $ch = curl_init();

        //set the url, number of POST vars, POST data
        curl_setopt($ch,CURLOPT_URL, $call_url);
        curl_setopt($ch,CURLOPT_POST, count($fields));
        curl_setopt($ch,CURLOPT_POSTFIELDS, $fields_string);
        curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);


        //execute post
        $result = curl_exec($ch);

        //close connection
        curl_close($ch);

        $response = json_decode($result, true);
        return $response['response_status'];
    }
}



echo THBS_API::getUsers();

Is very weird, but i think is because declaring variables is different in classes, is the problem i use privar $base_url? and how to solve this?

P.S: that is my first class ever, i worked fine with normal functions, but i still want to learn classes functions

Now i get

Notice: Undefined variable: fields_string in /srv/disk1/3203065/www/xxxxxxxxxxxxxxxxxx.com/API/clientapi.php on line 24

Line 44:

return $response['response_status'];

Code without class (working):

$base_url = $_SERVER['SERVER_NAME'];
  $url = "https://xxxxxxxxxxx.com/API/endsoftware.php";


  $fields = array(
    'API_USER' => urlencode('xxxxxx@xxxxx.xxxx'),
    'API_PASS' => urlencode('xxxxxxxxxx'),
    'CMD' => urlencode('getUserCount'));

//url-ify the data for the POST
foreach($fields as $key=>$value) { $fields_string .= $key.'='.$value.'&'; }
rtrim($fields_string, '&');

//open connection
$ch = curl_init();

//set the url, number of POST vars, POST data
curl_setopt($ch,CURLOPT_URL, $url);
curl_setopt($ch,CURLOPT_POST, count($fields));
curl_setopt($ch,CURLOPT_POSTFIELDS, $fields_string);
curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);


//execute post
$result = curl_exec($ch);

//close connection
curl_close($ch);

$response = json_decode($result, true);
echo $response['response_status'];

(returns "SUCCESS")

Answer 1

A couple of changes to your code.

• Since call_url is always going to be constant, you can declare it as a constant in your class.

• Second is your are concatenating $field values one by one with an & which is not needed. You can use http_build_query function for this.

• Third is you had curl_setopt($ch,CURLOPT_POST, count($fields)); which is incorrect since this says make a POST request only if we have more than 0 fields. You would want to make a proper request regardless of it. So, set it to true always.

Snippet:

<?php

namespace THBS_API;

class THBS_API{
    private const call_url = "https://xxxxxxxxxxx.com/API/endsoftware.php";

    public static function getUsers(){
        $base_url = $_SERVER['SERVER_NAME'];
        $fields = array(
            'API_USER' => urlencode('xxxxxx@xxxxxx.xxx'),
            'API_PASS' => urlencode('xxxxxxxxx'),
            'CMD' => urlencode('getUserCount'),
            'FROM' => urlencode($base_url)
        );

        //open connection
        $ch = curl_init();

        //set the url, number of POST vars, POST data
        curl_setopt($ch,CURLOPT_URL, self::call_url);
        curl_setopt($ch,CURLOPT_POST, true);
        curl_setopt($ch,CURLOPT_POSTFIELDS, http_build_query($fields));
        curl_setopt($ch,CURLOPT_SSL_VERIFYHOST,false); // add certificates once you have them(recommended)
        curl_setopt($ch,CURLOPT_SSL_VERIFYPEER,false);
        curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);

        //execute post
        $result = curl_exec($ch);

        //close connection
        curl_close($ch);

        $response = json_decode($result, true);
        return $response['response_status'];
    }
}


echo THBS_API::getUsers();

Update:

As @Dharman mentioned in the comments, you should always add certificates to your cURL requests to avoid man in the middle attacks attacks and this answer shows how you can add one to your cURL request.

Also, you can simply use http_build_query instead of individually encoding each one as http_build_query would do it anyway. So take off the urlencode from the above code.