Geary.php

<?php

/**
* Geary PHP API
*
* Access all API features of https://gear.mycelium.com
*
* @package  Geary
* @author   Mario Dian (http://freedomnode.com)
* @license  https://creativecommons.org/publicdomain/zero/1.0/ CC0 1.0 Universal
* @version  0.1
* @link     https://github.com/mariodian/geary
*/

if (!function_exists('getallheaders'))  {
    function getallheaders() {
        if (!is_array($_SERVER)) {
            return array();
        }

        $headers = array();
        foreach ($_SERVER as $name => $value) {
            if (substr($name, 0, 5) == 'HTTP_') {
                $headers[str_replace(' ', '-', ucwords(strtolower(str_replace('_', ' ', substr($name, 5)))))] = $value;
            }
        }
        return $headers;
    }
}

class Geary {
    const CONNECT_TIMEOUT = 60;
    const API_URL = 'https://gateway.gear.mycelium.com';

    private $gateway_id = '';
    private $gateway_secret = '';

    /**
    * @param string $gateway_id       Your API key obtained from https://admin.gear.mycelium.com/gateways
    * @param string $gateway_secret   Your API secret obtained from https://admin.gear.mycelium.com/gateways
    */
    public function __construct($gateway_id, $gateway_secret) {
        $this->gateway_id = $gateway_id;
        $this->gateway_secret = $gateway_secret;
    }

    /**
    * Create Order
    *
    * Create a new gateway order
    *
    * @param double $amount     Amount determines the amount to be paid for this 
    *                           order. The amount should be in the currency you 
    *                           have previously set for the gateway. If the 
    *                           gateway currency is BTC, then the amount is 
    *                           normally in satoshis
    * @param int $keychain_id   Keychain id is used to generate an address for 
    *                           the next order.
    * @return mixed
    */
    public function create_order($amount, $keychain_id, $callback_data) {
        $request = $this->endpoint('orders');
        $params = array(
            'amount' => $amount,
            'keychain_id' => $keychain_id,
            'callback_data' => $callback_data
        );

    	$data = array(
            'request_uri' => $request,
            'request_method' => 'POST',
            'params' => $params
    	);

    	return $this->send_signed_request($data);
    }
    
    /**
    * Cancel Order
    *
    * Cancel existing gateway order
    *
    * @param integer $id     Id is an existing order ID or payment ID
    * @return mixed
    */
    public function cancel_order($id) {
        $request = $this->endpoint('orders');

    	$data = array(
            'request_uri' => $request,
            'request_method' => 'POST',
            'params' => "$id/cancel"
    	);

    	return $this->send_signed_request($data);
    }
    
    /**
    * Check Order
    *
    * Check existing gateway order status
    *
    * @param integer $payment_id     Id is an existing payment ID
    * @return mixed
    */
    public function check_order($payment_id) {
        $request_uri = $this->endpoint('orders');

    	$data = array(
            'request_uri' => $request_uri,
            'request_method' => 'GET',
            'params' => $payment_id
    	);

    	return $this->send_signed_request($data);
    }
    
    /**
    * Check Order Callback
    *
    * Check for any order status changes via callback URL
    * 
    * @return mixed
    */
    public function check_order_callback() {
        $header_signature = $this->get_header('X-Signature');
        $request_path = $_SERVER['REQUEST_URI'];
        
        $nonce = NULL;
        $body = NULL;
        
        if (isset($_GET['after_payment_redirect_to']) && $after_payment_redirect_to = $_GET['after_payment_redirect_to']) {
            $_GET['after_payment_redirect_to'] = urlencode($after_payment_redirect_to);
        }
        
        $constant_digest = hash('sha512', $nonce . $body, TRUE);
        $payload = $_SERVER['REQUEST_METHOD'] . $request_path . $constant_digest;
        $raw_signature = hash_hmac('sha512', $payload, $this->gateway_secret, TRUE);
        $signature = base64_encode($raw_signature);
    
        if ($signature === $header_signature) {
            return array(
                'order_id'              => $_GET['order_id'],
                'amount'                => $_GET['amount'],
                'amount_in_btc'         => $_GET['amount_in_btc'],
                'amount_paid_in_btc'    => $_GET['amount_paid_in_btc'],
                'status'                => $_GET['status'],
                'address'               => $_GET['address'],
                'transaction_ids'       => $_GET['transaction_ids'],
                'callback_data'         => $_GET['callback_data'],
            );
        } else {
            return FALSE;
        }
    }
    
    /**
    * Order Websocket Link
    *
    * Get an order link for status monitoring via websocket
    *
    * @param integer $id     Id is an existing order ID
    * @return string
    */
    public function order_websocket_link($id) {
        return "wss://gateway.gear.mycelium.com/gateways/{$this->gateway_id}/orders/$id/websocket";
    }
    
    /**
    * Get Last Keychain Id
    *
    * Get a last keychain id for a specific gateway
    * 
    * @return mixed
    */
    public function get_last_keychain_id() {
        $request_uri = $this->endpoint('last_keychain_id');

    	$data = array(
            'request_uri' => $request_uri,
            'request_method' => 'GET',
            'params' => NULL
    	);

    	return $this->send_signed_request($data);
    }
    
    /**
    * Curl Error
    *
    * Output curl error if possible
    *
    * @param array $ch
    * @return boolean
    */
    private function curl_error($ch) {
    	if ($errno = curl_errno($ch)) {
            $error_message = curl_strerror($errno);
            echo "cURL error ({$errno}):\n {$error_message}";

            return FALSE;
    	}

    	return TRUE;
    }

    /**
    * Endpoint
    *
    * Construct an endpoint URL
    *
    * @param string $method
    * @return string
    */
    private function endpoint($method) {
    	return "/gateways/{$this->gateway_id}/$method";
    }
    
    /**
    * Get Params
    *
    * Construct URL parameters
    *
    * @param mixed $params
    * @return string
    */
    private function get_params($params){
        $parameters = '';
        
        if ($params !== NULL) {
            if (is_array($params)) {
                $parameters = '?';
                $parameters .= http_build_query($params);
            } else {
                $parameters = '/';
                $parameters .= $params;
            }
    	}
        
        return $parameters;
    }
    
    /**
    * Get Header
    *
    * Get single data frin header
    *
    * @param string $name
    * @return string
    */
    private function get_header($name) {
        $headers = getallheaders();
        
        if ($headers) {
            foreach ($headers as $key => $value) {
                if (strtolower($key) === strtolower($name)) {
                    return $value;
                }
            }
        }
        
        return '';
    }

    /**
    * Prepare Header
    *
    * Add data to header for authentication purpose
    *
    * @param array $data
    * @return array
    */
    private function prepare_header($data)
    {        
        $params = $data['params'];
        $params_query = !is_array($params) ? "/$params" : '?' . http_build_query($params);

        $nonce = (int) round(microtime(true) * 1000);
        $body = '';
        
        $nonce_hash = hash('sha512', (string) $nonce . $body, TRUE);
        $payload = $data['request_method'] . $data['request_uri'] . $params_query . $nonce_hash;
        $raw_signature = hash_hmac('sha512', $payload, $this->gateway_secret, TRUE);
        $signature = base64_encode($raw_signature);

    	return array(
            'X-Nonce: ' . $nonce,
            'X-Signature: ' . $signature
    	);
    }

    /**
    * Send Signed Request
    *
    * Send a signed HTTP request
    *
    * @param array $data
    * @return mixed
    */
    private function send_signed_request($data) {
    	$ch = curl_init();
    	$url = self::API_URL . $data['request_uri'];

    	$headers = $this->prepare_header($data);
        $params = $this->get_params($data['params']);

        $curl_data = array(
            CURLOPT_URL             => $url . $params,
            CURLOPT_RETURNTRANSFER  => TRUE,
            CURLOPT_HTTPHEADER      => $headers,
            CURLOPT_SSL_VERIFYPEER  => TRUE,
            CURLOPT_CONNECTTIMEOUT  => self::CONNECT_TIMEOUT,
            CURLOPT_POST            => ($data['request_method'] === 'POST')
    	);

    	curl_setopt_array($ch, $curl_data);

    	if (!$result = curl_exec($ch)) {
            return $this->curl_error($ch);
    	}
    	elseif (curl_getinfo($ch, CURLINFO_HTTP_CODE) !== 200) {
    	    echo "Error: $result";
            
            return FALSE;
    	} else {
            return json_decode($result);
    	}
    }
}