php CURL封装类

class Curl_Class  
{  
    function Curl_Class()  
    {  
        return true;  
    }  

    function execute($method, $url, $fields = '', $userAgent = '', $httpHeaders = '', $username = '', $password = '')  
    {  
        $ch = Curl_Class::create();  
        if (false === $ch)  
        {  
            return false;  
        }  

        if (is_string($url) && strlen($url))  
        {  
            $ret = curl_setopt($ch, CURLOPT_URL, $url);  
        }  
        else 
        {  
            return false;  
        }  
        //是否显示头部信息  
        curl_setopt($ch, CURLOPT_HEADER, false);  
        //  
        curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);  

        if ($username != '')  
        {  
            curl_setopt($ch, CURLOPT_USERPWD, $username . ':' . $password);  
        }  

        $method = strtolower($method);  
        if ('post' == $method)  
        {  
            curl_setopt($ch, CURLOPT_POST, true);  
            if (is_array($fields))  
            {  
                $sets = array();  
                foreach ($fields AS $key => $val)  
                {  
                    $sets[] = $key . '=' . urlencode($val);  
                }  
                $fields = implode('&',$sets);  
            }  
            curl_setopt($ch, CURLOPT_POSTFIELDS, $fields);  
        }  
        else if ('put' == $method)  
        {  
            curl_setopt($ch, CURLOPT_PUT, true);  
        }  

        //curl_setopt($ch, CURLOPT_PROGRESS, true);  
        //curl_setopt($ch, CURLOPT_VERBOSE, true);  
        //curl_setopt($ch, CURLOPT_MUTE, false);  
        curl_setopt($ch, CURLOPT_TIMEOUT, 3);//设置curl超时秒数，例如将信息POST出去3秒钟后自动结束运行。  

        if (strlen($userAgent))  
        {  
            curl_setopt($ch, CURLOPT_USERAGENT, $userAgent);  
        }  

        if (is_array($httpHeaders))  
        {  
            curl_setopt($ch, CURLOPT_HTTPHEADER, $httpHeaders);  
        }  

        $ret = curl_exec($ch);  

        if (curl_errno($ch))  
        {  
            curl_close($ch);  
            return array(curl_error($ch), curl_errno($ch));  
        }  
        else 
        {  
            curl_close($ch);  
            if (!is_string($ret) || !strlen($ret))  
            {  
                return false;  
            }  
            return $ret;  
        }  
    }  

    function post($url, $fields, $userAgent = '', $httpHeaders = '', $username = '', $password = '')  
    {  
        $ret = Curl_Class::execute('POST', $url, $fields, $userAgent, $httpHeaders, $username, $password);  
        if (false === $ret)  
        {  
            return false;  
        }  

        if (is_array($ret))  
        {  
            return false;  
        }  
        return $ret;  
    }  

    function get($url, $userAgent = '', $httpHeaders = '', $username = '', $password = '')  
    {  
        $ret = Curl_Class::execute('GET', $url, '', $userAgent, $httpHeaders, $username, $password);  
        if (false === $ret)  
        {  
            return false;  
        }  

        if (is_array($ret))  
        {  
            return false;  
        }  
        return $ret;  
    }  

    function create()  
    {  
        $ch = null;  
        if (!function_exists('curl_init'))  
        {  
            return false;  
        }  
        $ch = curl_init();  
        if (!is_resource($ch))  
        {  
            return false;  
        }  
        return $ch;  
    }  

}
//该片段来自于http://outofmemory.cn