<?php
class alipay_service
{
	var $gateway = "https://www.alipay.com/cooperate/gateway.do?";         //支付接口
	var $parameter;       //全部需要传递的参数
	var $security_code;  	//安全校验码
	var $mysign;             //签名

	//构造支付宝外部服务接口控制
	function alipay_service($parameter,$security_code,$sign_type = "MD5",$transport= "https")
	{
		$this->parameter      = $this->para_filter($parameter);
		$this->security_code  = $security_code;
		$this->sign_type      = $sign_type;
		$this->mysign         = '';
		$this->transport      = $transport;
		if($parameter['_input_charset'] == "")
		{
			$this->parameter['_input_charset']='GBK';
		}
		if($this->transport == "https")
		{
			$this->gateway = "https://www.alipay.com/cooperate/gateway.do?";
		}
		else
		{
			$this->gateway = "http://www.alipay.com/cooperate/gateway.do?";
		}
		$sort_array = array();
		$arg = "";
		$sort_array = $this->arg_sort($this->parameter);
		while (list ($key, $val) = each ($sort_array))
		{
			$arg.=$key."=".$this->charset_encode($val,$this->parameter['_input_charset'])."&";
		}
		$prestr = substr($arg,0,count($arg)-2);  //去掉最后一个问号
		$this->mysign = $this->sign($prestr.$this->security_code);
	}

	function create_url()
	{
		$url = $this->gateway;
		$sort_array = array();
		$arg = "";
		$sort_array = $this->arg_sort($this->parameter);
		while (list ($key, $val) = each ($sort_array))
		{
			$arg.=$key."=".urlencode($this->charset_encode($val,$this->parameter['_input_charset']))."&";
		}
		$url.= $arg."sign=" .$this->mysign ."&sign_type=".$this->sign_type;
		return $url;
	}

	function arg_sort($array)
	{
		ksort($array);
		reset($array);
		return $array;
	}

	function sign($prestr)
	{
		$mysign = "";
		if($this->sign_type == 'MD5')
		{
			$mysign = md5($prestr);
		}
		elseif($this->sign_type =='DSA')
		{

			//DSA 签名方法待后续开发
			die("DSA 签名方法待后续开发，请先使用MD5签名方式");
		}
		else
		{
			die("支付宝暂不支持".$this->sign_type."类型的签名方式");
		}
		return $mysign;
	}

	function para_filter($parameter)
	{

		//除去数组中的空值和签名模式
		$para = array();
		while (list ($key, $val) = each ($parameter))
		{
			if($key == "sign" || $key == "sign_type" || $val == "")
			{
				continue;
			}
			else
			{
				$para[$key] = $parameter[$key];
			}

		}
		return $para;
	}

	//实现多种字符编码方式
	function charset_encode($input,$_output_charset ,$_input_charset ="GBK" )
	{
		$output = "";
		if(!isset($_output_charset) )
		{
			$_output_charset  = $this->parameter['_input_charset '];
		}
		if($_input_charset == $_output_charset || $input ==null)
		{
			$output = $input;
		}
		elseif (function_exists("mb_convert_encoding"))
		{
			$output = mb_convert_encoding($input,$_output_charset,$_input_charset);
		}
		elseif(function_exists("iconv"))
		{
			$output = iconv($_input_charset,$_output_charset,$input);
		}
		else
		{
			die("sorry, you have no libs support for charset change.");
		}
		return $output;
	}
}
?>