PayPal API Requests

Paypal.php

<?php

class Paypal
{
    /**
     * API Version
     */
    const VERSION = 51.0;

    /**
     * List of valid API environments
     * @var array
     */
    private $allowedEnvs = array(
        'beta-sandbox',
        'live',
        'sandbox'
    );

    /**
     * Config storage from constructor
     * @var array
     */
    private $config = array();

    /**
     * URL storage based on environment
     * @var string
     */
    private $url;

    /**
     * Build PayPal API request
     * 
     * @param string $username
     * @param string $password
     * @param string $signature
     * @param string $environment
     */
    public function __construct($username, $password, $signature, $environment = 'live')
    {
        if (!in_array($environment, $this->allowedEnvs)) {
            throw new Exception('Specified environment is not allowed.');
        }
        $this->config = array(
            'username'    => $username,
            'password'    => $password,
            'signature'   => $signature,
            'environment' => $environment
        );
    }

    /**
     * Make a request to the PayPal API
     * 
     * @param  string $method API method (e.g. GetBalance)
     * @param  array  $params Additional fields to send in the request (e.g. array('RETURNALLCURRENCIES' => 1))
     * @return array
     */
    public function call($method, array $params = array())
    {
        $fields = $this->encodeFields(array_merge(
            array(
                'METHOD'    => $method
                'VERSION'   => self::VERSION,
                'USER'      => $this->config['username'],
                'PWD'       => $this->config['password'],
                'SIGNATURE' => $this->config['signature']
            ),
            $params
        ));
        $ch = curl_init();
        curl_setopt($ch, CURLOPT_URL, $this->getUrl());
        curl_setopt($ch, CURLOPT_POST, count($fields));
        curl_setopt($ch, CURLOPT_POSTFIELDS, http_build_query($fields));
        curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
        $response = curl_exec($ch);
        if (!$response) {
            throw new Exception('Failed to contact PayPal API: ' . curl_error($ch) . ' (Error No. ' . curl_errno($ch) . ')');
        }
        curl_close($ch);
        parse_str($response, $result);
        return $this->decodeFields($result);
    }

    /**
     * Prepare fields for API
     * 
     * @param  array  $fields
     * @return array
     */
    private function encodeFields(array $fields)
    {
        return array_map('urlencode', $fields);
    }

    /**
     * Make response readable
     * 
     * @param  array  $fields
     * @return array
     */
    private function decodeFields(array $fields)
    {
        return array_map('urldecode', $fields);
    }

    /**
     * Get API url based on environment
     * 
     * @return string
     */
    private function getUrl()
    {
        if (is_null($this->url)) {
            switch ($this->config['environment']) {
                case 'sandbox':
                case 'beta-sandbox':
                    $this->url = "https://api-3t.$environment.paypal.com/nvp";
                    break;
                default:
                    $this->url = 'https://api-3t.paypal.com/nvp';
            }
        }
        return $this->url;
    }
}

And All schedure to send payment any some user

Great work! But please fix the missing comma on line 64 as pointed out by Nemonaut. Otherwise, you will get an error message similar to this one:

Parse error: syntax error, unexpected ''VERSION'' (T_CONSTANT_ENCAPSED_STRING), expecting ')' in /path/Paypal.php on line 65

You are a Great Time Save ;)