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=35703636de2f9df2a77a662b68e521ce17c34db4×tamp=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 ?>