PHP实现模拟微信公众号开发者模式

$url = 'http://xxxx.com/test/aaaa/index.php';//开发者URL
				$token = 'weixin';//TOKEN

                $timestamp = $_GET["timestamp"];
                $nonce = $_GET["nonce"];
                $tmpArr = array($token, $timestamp, $nonce);
	            sort($tmpArr, SORT_STRING);
	            $tmpStr = implode( $tmpArr );
	            $tmpStr = sha1( $tmpStr );
                $url .= stripos($url, '?') === false ? '?' : '&';
                $url .= http_build_query(array(
                      'signature' => $tmpStr,
                      'timestamp' => $timestamp,
                      'nonce' => $nonce,
                ));
				//echo $url;
				//如果不是项目相关的事件 $returnStr返回空
				$header = array();
				//这个要加上啊
				$header[] = "Content-type: text/xml";//定义content-type为xml
				$ch = curl_init();
				curl_setopt($ch, CURLOPT_URL, $url);
                curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
                curl_setopt($ch, CURLOPT_HTTPHEADER, $header);
                curl_setopt($ch, CURLOPT_POST, 1);
                curl_setopt($ch, CURLOPT_POSTFIELDS, $postStr);
				//curl_setopt($ch, CURLOPT_POSTFIELDS, $pp);
				$response = curl_exec($ch);
				if(curl_errno($ch)){
				    error_log (curl_error($ch));
				}
				curl_close($ch);
				echo $response;//返回给微信服务器