微信公众号接入初始化文件（php）

//define your token
define("TOKEN", "your token");
$wechatObj = new wechatCallbackapiTest();
$wechatObj->valid();

class wechatCallbackapiTest {
	public function valid()
	{
		$echoStr = $_GET["echostr"];
		//valid signature , option
		if($this->checkSignature()){
		echo $echoStr;
		exit;
		}
	}
	public function responseMsg()
	{
		//get post data, May be due to the different environments
		$postStr = $GLOBALS["HTTP_RAW_POST_DATA"];
		//extract post data
		if (!emptyempty($postStr)){
		$postObj = simplexml_load_string($postStr, 'SimpleXMLElement', LIBXML_NOCDATA);
		$fromUsername = $postObj->FromUserName;
		$toUsername = $postObj->ToUserName;
		$keyword = trim($postObj->Content);
		$time = time();
		$textTpl = "<xml>
		<ToUserName><![CDATA[%s]]></ToUserName>
		<FromUserName><![CDATA[%s]]></FromUserName>
		<CreateTime>%s</CreateTime>
		<MsgType><![CDATA[%s]]></MsgType>
		<Content><![CDATA[%s]]></Content>
		<FuncFlag>0</FuncFlag>
		</xml>";
		
		if(!emptyempty( $keyword ))
		{
			$msgType = "text";
			$contentStr = "Welcome to wechat world!";
			$resultStr = sprintf($textTpl, $fromUsername, $toUsername, $time, $msgType, $contentStr);
			echo $resultStr;
		}else{
			echo "Input something...";
		}
		}else {
			echo "";
			exit;
		}
	}
	private function checkSignature()
	{
		$signature = $_GET["signature"];
		$timestamp = $_GET["timestamp"];
		$nonce = $_GET["nonce"];
		$token = TOKEN;
		$tmpArr = array($token, $timestamp, $nonce);
		sort($tmpArr, SORT_STRING);
		$tmpStr = implode( $tmpArr );
		$tmpStr = sha1( $tmpStr );
		if( $tmpStr == $signature ){
			return true;
		}else{
			return false;
		}
	}

}

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