微信公众平台开发:从零基础到ThinkPHP5高性能框架实践
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3.3.5 消息体加/解密实现

在图3-21中,微信公众平台在配置服务器时,提供了3种加解密模式供开发者选择,即“明文模式”、“兼容模式”、“安全模式(推荐)”。选择“兼容模式”和“安全模式(推荐)”前,需在开发者中心填写AES对称加密算法的消息加解密密钥EncodingAESKey。公众号用此密钥对收到的密文消息体进行解密,回复消息体也用此密钥加密。

●明文模式:维持现有模式,没有适配加解密新特性,消息体明文收发,默认设置为明文模式。

●兼容模式:公众平台发送消息内容将同时包括明文和密文,消息包长度增加到原来的3倍左右;公众号回复明文或密文均可,不影响现有消息收发;开发者可在此模式下进行调试。

●安全模式(推荐):公众平台发送消息体的内容只含有密文,公众号回复的消息体也为密文,建议开发者在调试成功后使用此模式收发消息。

消息体加解密的实现过程如下。

假设本次的开发配置中URL为

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

接口程序中需要配置以下3个参数。

/*
    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');

当用户向公众号发送消息时,微信公众号将会在URL中带上signature、timestamp、nonce、encrypt_type、msg_signature等参数,类似如下。

http:// www.fangbei.org/index.php? signature=35703636de2f9df2a77a662b68e521ce17c34d b4&timestamp=1414243737&nonce=1792106704&encrypt_type=aes&msg_signature=61479843 31daf7a1a9eed6e0ec3ba69055256154

同时向该接口推送如下XML消息,即一个已加密的消息。

<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>

这时程序需要从URL中获得以下参数。这些参数将用于加解密过程。

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

接口程序收到消息后,先进行解密,解密部分代码如下。

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

解密完成后,把解密内容又返回给$postStr,这是为了将消息中解密后的内容和明文模式时的消息统一,方便后续处理。解密后的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>

对消息在自己的原有的代码流程中处理,完成之后,一个要回复的文本消息如下。

<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
    技术支持 方倍工作室
    http:// www.fangbei.org/]]></Content>
</xml>

把上述消息加密,返回给微信公众号,加密过程如下。

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

加密后的内容如下。

<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>

这样一个安全模式下的加解密消息就完成了。

完整的代码如下。

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     //验证签名
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     //响应消息
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 = "";  //解密后的明文
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              //消息类型分离
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 = ''; //加密后的密文
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 = "欢迎关注方倍工作室 ";
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              $content = "这是个文本消息";
105         }else if(strstr($keyword, "单图文")){
106              $content = array();
107             $content[] = array("Title"=>"单图文标题",  "Description"=>"单图文内
        容", "PicUrl"=>"http://discuz.comli.com/weixin/weather/icon/cartoon.jpg",
        "Url" =>"http://m.cnblogs.com/? u=txw1958");
108         }else if(strstr($keyword, "图文")|| strstr($keyword, "多图文")){
109              $content = array();
110             $content[] = array("Title"=>"多图文1标题", "Description"=>"", "Pic
        Url"=>"http://discuz.comli.com/weixin/weather/icon/cartoon.jpg", "Url" =>
        "http:// m.cnblogs.com/? u=txw1958");
111             $content[] = array("Title"=>"多图文2标题", "Description"=>"", "Pic
        Url"=>"http:// d.hiphotos.bdimg.com/wisegame/pic/item/f3529822720e0cf3ac
        9f1ada0846f21fbe09aaa3.jpg", "Url" =>"http://m.cnblogs.com/? u=txw1958");
112             $content[] = array("Title"=>"多图文3标题", "Description"=>"", "Pic
        Url"=>"http:// g.hiphotos.bdimg.com/wisegame/pic/item/18cb0a46f21fbe090d33
        8acc6a600c338644adfd.jpg", "Url" =>"http://m.cnblogs.com/? u=txw1958");
113         }else if(strstr($keyword, "音乐")){
114              $content = array();
115              $content = array("Title"=>"最炫民族风", "Description"=>"歌手:凤凰传
        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技术支持 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 $result;
130     }
131
132     //回复文本消息
133     private function transmitText($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 $result;
144     }
145
146     //回复图文消息
147     private function transmitNews($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 $result;
175     }
176
177     //回复音乐消息
178     private function transmitMusic($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 $result;
199     }
200
201     //日志记录
202     public function logger($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 ? >