BTCChina API (PHP < 5.4)

<?php

namespace Bitcoin\BTCChina;

class API
{
    protected $key;

    protected $secret;

    public function __construct($key, $secret)
    {
        $this->key = $key;

        $this->secret = $secret;
    }

    public function request($method, $methodParameters = array())
    {
        list($usec, $sec) = explode(' ', microtime());
        $tonce = $sec . substr($usec, 2, 6);

        $queryString = sprintf(
            'tonce=%s&accesskey=%s&requestmethod=post&id=%s&method=%s&params=%s',
            $tonce,
            $this->key,
            $tonce,
            $method,
            implode(',', $methodParameters)
        );

        $hash = hash_hmac('sha1',$queryString, $this->secret);
        $basicAuthentication = base64_encode($this->key . ':' . $hash);

        $headers = array(
            'Content-Type: application/json-rpc',
            'Authorization: Basic ' . $basicAuthentication,
            'Json-Rpc-Tonce: ' . $tonce,
        );

        $postData = json_encode(array(
            'method' => $method,
            'params' => $methodParameters,
            'id' => $tonce
        ));

        $ch = curl_init();
        curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
        curl_setopt($ch, CURLOPT_URL, 'https://api.btcchina.com/api_trade_v1.php');
        curl_setopt($ch, CURLOPT_POSTFIELDS, $postData);
        curl_setopt($ch, CURLOPT_HTTPHEADER, $headers);
        curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, FALSE);

        $res = curl_exec($ch);
        return json_decode($res, true);
    }

    public function cpm()
    {
        return 0;
    }

    public function openOrders()
    {
        $orders = $this->request('getOrders');

        return $orders['result']['order'];
    }

    public function getAccountInfo()
    {
        $accountInfo = $this->request('getAccountInfo');

        return $accountInfo['result'];
    }

    public function marketDepth()
    {
        $response = $this->request('getMarketDepth2');

        return $response['result']['market_depth'];
    }

    public function buy($amount, $price)
    {
        $response = $this->request('buyOrder', array($price, $amount));

        return $response['result'];
    }

    public function sell($amount, $price)
    {
        $response = $this->request('sellOrder', array($price, $amount));

        return $response['result'];
    }
}