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3.3.5 消息體加/解密實現

在圖3-21中，微信公眾平台在配置服務器時，提供了3種加解密模式供開發者選擇，即「明文模式」、「兼容模式」、「安全模式（推薦）」。選擇「兼容模式」和「安全模式（推薦）」前，需在開發者中心填寫AES對稱加密算法的消息加解密密鑰EncodingAESKey。公眾號用此密鑰對收到的密文消息體進行解密，回復消息體也用此密鑰加密。

·明文模式：維持現有模式，沒有適配加解密新特性，消息體明文收發，默認設置為明文模式。

·兼容模式：公眾平台發送消息內容將同時包括明文和密文，消息包長度增加到原來的3倍左右；公眾號回復明文或密文均可，不影響現有消息收發；開發者可在此模式下進行調試。

·安全模式（推薦）：公眾平台發送消息體的內容只含有密文，公眾號回復的消息體也為密文，建議開發者在調試成功後使用此模式收發消息。

消息體加解密的實現過程如下。

假設本次的開發配置中URL為 

http:// www.fangbei.org/index.php

接口程序中需要配置以下3個參數。 

/*
    方倍工作室 http:// www.cnblogs.com/txw1958/
    CopyRight 2014 All Rights Reserved
*/
define("TOKEN", "weixin");
define("AppID", "wxbad0b45542aa0b5e");
define("EncodingAESKey", "abcdefghijklmnopqrstuvwxyz0123456789ABCDEFG");
require_once('wxBizMsgCrypt.php');

當用戶向公眾號發送消息時，微信公眾號將會在URL中帶上signature、timestamp、nonce、encrypt_type、msg_signature等參數，類似如下。 

http:// www.fangbei.org/index.php?signature=35703636de2f9df2a77a662b68e521ce17c34db4&timestamp=1414243737&nonce=1792106704&encrypt_type=aes&msg_signature=61479843
31daf7a1a9eed6e0ec3ba69055256154

同時向該接口推送如下XML消息，即一個已加密的消息。 

<xml> 
    <ToUserName><![CDATA[gh_680bdefc8c5d]]></ToUserName>  
    <Encrypt><![CDATA[MNn4+jJ/VsFh2gUyKAaOJArwEVYCvVmyN0iXzNarP3O6vXzK62ft1/KG2/
    XPZ4y5bPWU/jfIfQxODRQ7sLkUsrDRqsWimuhIT8Eq+w4E/28m+XDAQKEOjWTQIOp1p6kNsIV1Dd
    C3B+AtcKcKSNAeJDr7x7GHLx5DZYK09qQsYDOjP6R5NqebFjKt/NpEl/GU3gWFwG8LCtRNuIYdK5
    axbFSfmXbh5CZ6Bk5wSwj5fu5aS90cMAgUhGsxrxZTY562QR6c+3ydXxb+GHI5w+qA+eqJjrQqR7
    u5hS+1x5sEsA7vS+bZ5LYAR3+PZ243avQkGllQ+rg7a6TeSGDxxhvLw+mxxinyk88BNHkJnyK// hM
    1k9PuvuLAASdaud4vzRQlAmnYOslZl8CN7gjCjV41skUTZv3wwGPxvEqtm/nf5fQ=]]></Encrypt>
</xml>

這時程序需要從URL中獲得以下參數。這些參數將用於加解密過程。 

$timestamp  = $_GET['timestamp'];
$nonce = $_GET["nonce"];
$msg_signature  = $_GET['msg_signature'];
$encrypt_type = $_GET['encrypt_type'];

接口程序收到消息後，先進行解密，解密部分代碼如下。 

$postStr = $GLOBALS["HTTP_RAW_POST_DATA"];
if ($encrypt_type == 'aes'){
    $pc = new WXBizMsgCrypt(TOKEN, EncodingAESKey, AppID);
    $this->logger(" D \r\n".$postStr);
    $decryptMsg = "";  // 解密後的明文
    $errCode = $pc->DecryptMsg($msg_signature, $timestamp, $nonce, $postStr, $decryptMsg);
    $postStr = $decryptMsg;
}

解密完成後，把解密內容又返回給$postStr，這是為了將消息中解密後的內容和明文模式時的消息統一，方便後續處理。解密後的XML如下。 

<xml>
    <ToUserName><![CDATA[gh_680bdefc8c5d]]></ToUserName>
    <FromUserName><![CDATA[oIDrpjpQ8j8mBuQ8nM26HWzNEZgg]]></FromUserName>
    <CreateTime>1414243737</CreateTime>
    <MsgType><![CDATA[text]]></MsgType>
    <Content><![CDATA[?]]></Content>
    <MsgId>6074130599188426998</MsgId>
</xml>

對消息在自己的原有的代碼流程中處理，完成之後，一個要回復的文本消息如下。 

<xml>
    <ToUserName><![CDATA[oIDrpjpQ8j8mBuQ8nM26HWzNEZgg]]></ToUserName>
    <FromUserName><![CDATA[gh_680bdefc8c5d]]></FromUserName>
    <CreateTime>1414243733</CreateTime>
    <MsgType><![CDATA[text]]></MsgType>
    <Content><![CDATA[2014-10-25 21:28:53
    技術支持 方倍工作室
    http:// www.fangbei.org/]]></Content>
</xml>

把上述消息加密，返回給微信公眾號，加密過程如下。 

// 加密
if ($encrypt_type == 'aes'){
    $encryptMsg = ''; // 加密後的密文
    $errCode = $pc->encryptMsg($result, $timeStamp, $nonce, $encryptMsg);
    $result = $encryptMsg;
    $this->logger(" E \r\n".$result);
}

加密後的內容如下。 

<xml> 
    <Encrypt><![CDATA[pE6gp6qvVBMHwCXwnM7illFBrh9LmvlKFlPUDuyQo9EKNunqbUFMd2Kj
    iYoz+3K1B+93JbMWHt+19TI8awdRdyopRS4oUNg5M2jwpwXTmc6TtafkKNjvqlvPXIWmutw0tuMXke
    1hDgsqz0SC8h/QjNLxECuwnczrfCMJlt+APHnX2yMMaq/aYUNcndOH387loQvl2suCGucXpglnbx
    f7frTCz9NQVgKiYrvKOhk6KFiVMnzuxy6WWmoe3GBiUCPTtYf5b1CxzN2IHViEBm28ilV9wWdNOM
    9TPG7BSSAcpgY4pcwdIG5+4KhgYmnVU3bc/ZJkk42TIdidigOfFpJwET4UWVrLB/ldUud4aPexp
    3aPCR3Fe53S2HHcl3tTxh4iRvDftUKP3svYPctt1MlYuYv/BZ4JyzUQV03H+0XrVyDY2tyVjimgC
    rA2c1mZMgHttOHTQ6VTnxrMq0GWlRlH0KPQKqtjUpNQzuOH4upQ8boPsEtuY3wDA2RaXQPJrX
    on]]></Encrypt>  
    <MsgSignature><![CDATA[6c46904dc1f58b2ddf2dd0399f1c6cf41f33ecb9]]></MsgSignature>
    <TimeStamp>1414243733</TimeStamp>  
    <Nonce><![CDATA[1792106704]]></Nonce>
</xml>

這樣一個安全模式下的加解密消息就完成了。

完整的代碼如下。 

  1 <?php
  2 /*
  3     方倍工作室 http:// www.cnblogs.com/txw1958/
  4     CopyRight 2014 All Rights Reserved
  5 */
  6 define("TOKEN", "weixin");
  7 define("AppID", "wxbad0b45542aa0b5e");
  8 define("EncodingAESKey", "abcdefghijklmnopqrstuvwxyz0123456789ABCDEFG");
  9 require_once('wxBizMsgCrypt.php');
 10 
 11 $wechatObj = new wechatCallbackapiTest;
 12 if (!isset($_GET['echostr'])) {
 13     $wechatObj->responseMsg;
 14 }else{
 15     $wechatObj->valid;
 16 }
 17 
 18 class wechatCallbackapiTest
 19 {
 20     // 驗證簽名
 21     public function valid
 22     {
 23         $echoStr = $_GET["echostr"];
 24         $signature = $_GET["signature"];
 25         $timestamp = $_GET["timestamp"];
 26         $nonce = $_GET["nonce"];
 27         $tmpArr = array(TOKEN, $timestamp, $nonce);
 28         sort($tmpArr);
 29         $tmpStr = implode($tmpArr);
 30         $tmpStr = sha1($tmpStr);
 31         if($tmpStr == $signature){
 32             echo $echoStr;
 33             exit;
 34         }
 35     }
 36 
 37     // 響應消息
 38     public function responseMsg
 39     {
 40         $timestamp  = $_GET['timestamp'];
 41         $nonce = $_GET["nonce"];
 42         $msg_signature  = $_GET['msg_signature'];
 43         $encrypt_type = (isset($_GET['encrypt_type']) && ($_GET['encrypt_type'] 
            == 'aes')) ? "aes" : "raw";
 44         
 45         $postStr = $GLOBALS["HTTP_RAW_POST_DATA"];
 46         if (!empty($postStr)){
 47             // 解密
 48             if ($encrypt_type == 'aes'){
 49                 $pc = new WXBizMsgCrypt(TOKEN, EncodingAESKey, AppID);                
 50                 $this->logger(" D \r\n".$postStr);
 51                 $decryptMsg = "";  // 解密後的明文
 52                 $errCode = $pc->DecryptMsg($msg_signature, $timestamp, $nonce, 
                    $postStr, $decryptMsg);
 53                 $postStr = $decryptMsg;
 54             }
 55             $this->logger(" R \r\n".$postStr);
 56             $postObj = simplexml_load_string($postStr, 'SimpleXMLElement', LIBXML_
                NOCDATA);
 57             $RX_TYPE = trim($postObj->MsgType);
 58 
 59             // 消息類型分離
 60             switch ($RX_TYPE)
 61             {
 62                 case "event":
 63                     $result = $this->receiveEvent($postObj);
 64                     break;
 65                 case "text":
 66                     $result = $this->receiveText($postObj);
 67                     break;
 68             }
 69             $this->logger(" R \r\n".$result);
 70             // 加密
 71             if ($encrypt_type == 'aes'){
 72                 $encryptMsg = ''; // 加密後的密文
 73                 $errCode = $pc->encryptMsg($result, $timeStamp, $nonce, $encry
                    ptMsg);
 74                 $result = $encryptMsg;
 75                 $this->logger(" E \r\n".$result);
 76             }
 77             echo $result;
 78         }else {
 79             echo "";
 80             exit;
 81         }
 82     }
 83 
 84     // 接收事件消息
 85     private function receiveEvent($object)
 86     {
 87         $content = "";
 88         switch ($object->Event)
 89         {
 90             case "subscribe":
 91                 $content = "歡迎關注方倍工作室 ";
 92                 break;
 93         }
 94 
 95         $result = $this->transmitText($object, $content);
 96         return $result;
 97     }
 98 
 99     // 接收文本消息
100     private function receiveText($object)
101     {
102         $keyword = trim($object->Content);
103         if (strstr($keyword, "文本")){
104             $content = "這是個文本消息";
105         }else if (strstr($keyword, "單圖文")){
106             $content = array;
107             $content = array("Title"=>"單圖文標題",  "Description"=>"單圖文內
        容", "PicUrl"=>"http:// discuz.comli.com/weixin/weather/icon/cartoon.jpg", 
        "Url" =>"http:// m.cnblogs.com/?u=txw1958");
108         }else if (strstr($keyword, "圖文") || strstr($keyword, "多圖文")){
109             $content = array;
110             $content = array("Title"=>"多圖文1標題", "Description"=>"", "Pic
        Url"=>"http:// discuz.comli.com/weixin/weather/icon/cartoon.jpg", "Url" =>
        "http:// m.cnblogs.com/?u=txw1958");
111             $content = array("Title"=>"多圖文2標題", "Description"=>"", "Pic
        Url"=>"http:// d.hiphotos.bdimg.com/wisegame/pic/item/f3529822720e0cf3ac
        9f1ada0846f21fbe09aaa3.jpg", "Url" =>"http:// m.cnblogs.com/?u=txw1958");
112             $content = array("Title"=>"多圖文3標題", "Description"=>"", "Pic
        Url"=>"http:// g.hiphotos.bdimg.com/wisegame/pic/item/18cb0a46f21fbe090d33
        8acc6a600c338644adfd.jpg", "Url" =>"http:// m.cnblogs.com/?u=txw1958");
113         }else if (strstr($keyword, "音樂")){
114             $content = array;
115             $content = array("Title"=>"最炫民族風", "Description"=>"歌手：鳳凰傳
        奇", "MusicUrl"=>"http:// 121.199.4.61/music/zxmzf.mp3", "HQMusicUrl"=>
        "http:// 121.199.4.61/music/zxmzf.mp3");
116         }else{
117             $content = date("Y-m-d H:i:s",time)."\n".$object->FromUserName.
        "\n技術支持 方倍工作室";
118         }
119 
120         if(is_array($content)){
121             if (isset($content[0])){
122                 $result = $this->transmitNews($object, $content);
123             }else if (isset($content['MusicUrl'])){
124                 $result = $this->transmitMusic($object, $content);
125             }
126         }else{
127             $result = $this->transmitText($object, $content);
128         }
129         return $result;
130     }
131 
132     // 回覆文本消息
133     private function transmitText($object, $content)
134     {
135         $xmlTpl = "<xml>
136                    <ToUserName><![CDATA[%s]]></ToUserName>
137                    <FromUserName><![CDATA[%s]]></FromUserName>
138                    <CreateTime>%s</CreateTime>
139                    <MsgType><![CDATA[text]]></MsgType>
140                    <Content><![CDATA[%s]]></Content>
141                    </xml>";
142         $result = sprintf($xmlTpl, $object->FromUserName, $object->ToUserName, time, 
        $content);
143         return $result;
144     }
145 
146     // 回復圖文消息
147     private function transmitNews($object, $newsArray)
148     {
149         if(!is_array($newsArray)){
150             return;
151         }
152         $itemTpl = "<item>
153                     <Title><![CDATA[%s]]></Title>
154                     <Description><![CDATA[%s]]></Description>
155                     <PicUrl><![CDATA[%s]]></PicUrl>
156                     <Url><![CDATA[%s]]></Url>
157                     </item>";
158         
159         $item_str = "";
160         foreach ($newsArray as $item){
161             $item_str .= sprintf($itemTpl, $item['Title'], $item['Description'], 
        $item['PicUrl'], $item['Url']);
162         }
163         $xmlTpl = "<xml>
164                    <ToUserName><![CDATA[%s]]></ToUserName>
165                    <FromUserName><![CDATA[%s]]></FromUserName>
166                    <CreateTime>%s</CreateTime>
167                    <MsgType><![CDATA[news]]></MsgType>
168                    <ArticleCount>%s</ArticleCount>
169                    <Articles>
170                    $item_str    </Articles>
171                    </xml>";
172 
173         $result = sprintf($xmlTpl, $object->FromUserName, $object->ToUserName, 
        time, count($newsArray));
174         return $result;
175     }
176 
177     // 回復音樂消息
178     private function transmitMusic($object, $musicArray)
179     {
180         $itemTpl = "<Music>
181                     <Title><![CDATA[%s]]></Title>
182                     <Description><![CDATA[%s]]></Description>
183                     <MusicUrl><![CDATA[%s]]></MusicUrl>
184                     <HQMusicUrl><![CDATA[%s]]></HQMusicUrl>
185                     </Music>";
186 
187         $item_str = sprintf($itemTpl, $musicArray['Title'], $musicArray['Des
        cription'], $musicArray['MusicUrl'], $musicArray['HQMusicUrl']);
188 
189         $xmlTpl = "<xml>
190                    <ToUserName><![CDATA[%s]]></ToUserName>
191                    <FromUserName><![CDATA[%s]]></FromUserName>
192                    <CreateTime>%s</CreateTime>
193                    <MsgType><![CDATA[music]]></MsgType>
194                    $item_str
195                    </xml>";
196 
197         $result = sprintf($xmlTpl, $object->FromUserName, $object->ToUserName, 
        time);
198         return $result;
199     }
200 
201     // 日誌記錄
202     public function logger($log_content)
203     {
204         if(isset($_SERVER['HTTP_APPNAME'])){                        // SAE
205             sae_set_display_errors(false);
206             sae_debug($log_content);
207             sae_set_display_errors(true);
208         }else if($_SERVER['REMOTE_ADDR'] != "127.0.0.1"){        // LOCAL
209             $max_size = 500000;
210             $log_filename = "log.xml";
211             if(file_exists($log_filename) and (abs(filesize($log_filename)) > $max_
        size)){unlink($log_filename);}
212             file_put_contents($log_filename, date('Y-m-d H:i:s').$log_content."\r
        \n", FILE_APPEND);
213         }
214     }
215 }
216 ?>
    微信公眾平台開發：從零基礎到ThinkPHP5高性能框架實踐