在这篇教程中，我们将介绍如何在微信公众平台上开发天气预报功能。我们将使用中国天气网的气象数据接口来获取天气信息。

这篇教程将介绍以下内容：

1. 获取中国天气网的气象数据
2. 在微信公众平台中回复天气

一、中国天气网

中国天气网提供了丰富的气象数据接口。下面我们介绍主要的几个：

国家根节点接口：

http://Flash.weather.com.cn/wmaps/xml/china.xml

该接口以XML格式列出所有的省（自治区、直辖市）的中文名称（quName）和拼音名称（pyName）及省会城市的天气信息，其中广东的数据如下：

<city quName="广东" pyName="guangdong" cityname="广州" state1="2" state2="7" stateDetailed="阴转小雨" tem1="8" tem2="15" windState="微风"/>

该接口的主要功能是通过它获取省级节点的拼音名称。以广东为例：其pyName是“Guangdong”。

省级节点接口（以广东为例）：

http://flash.weather.com.cn/wmaps/xml/Guangdong.xml

该接口以XML格式列出当前省下辖所有市的中文名称（quName）、拼音名称（pyName）、中心坐标、天气信息以及城市编码。其中深圳的数据如下所示：

<city cityX="409" cityY="257" cityname="深圳" centername="深圳" fontColor="FFFFFF" pyName="shenzhen" state1="1" state2="1" stateDetailed="多云" tem1="12" tem2="18" temNow="12" windState="微风" windDir="东北风" windPower="1级" humidity="74%" time="21:15" url="101280601"/>

在这个接口中主要获取城市名称及相应的城市编码。例如，深圳的城市编码为：101280601。可以编写程序将全国城市拓扑结构采集下来。也可以使用方倍工作室已经采集好的，点击这里下载。

实时天气数据（以深圳为例）：

http://www.weather.com.cn/data/sk/101280601.html

该接口以JSON格式列出当前城市的实时天气状况。如下所示：

{    "weatherinfo": {        "city": "深圳",        "cityid": "101280601",        "temp": "12",        "WD": "东北风",        "WS": "1级",        "SD": "75%",        "WSE": "1",        "time": "21:20",        "isRadar": "1",        "Radar": "JC_RADAR_AZ9755_JB"    }}

实时天气数据参数说明下所示：

六日天气数据（以深圳为例）：

http://m.weather.com.cn/data/101280601.html

该接口以JSON格式列出当前城市的六日天气状况。如下所示：

{    "weatherinfo": {        "city": "深圳",        "city_en": "shenzhen",        "date_y": "2014年2月15日",        "date": "",        "week": "星期六",        "fchh": "18",        "cityid": "101280601",        "temp1": "12℃~18℃",        "temp2": "16℃~21℃",        "temp3": "17℃~23℃",        "temp4": "11℃~18℃",        "temp5": "10℃~15℃",        "temp6": "12℃~17℃",        "tempF1": "53.6℉~64.4℉",        "tempF2": "60.8℉~69.8℉",        "tempF3": "62.6℉~73.4℉",        "tempF4": "51.8℉~64.4℉",        "tempF5": "50℉~59℉",        "tempF6": "53.6℉~62.6℉",        "weather1": "多云",        "weather2": "阴",        "weather3": "多云",        "weather4": "中雨",        "weather5": "多云",        "weather6": "阴",        "img1": "1",        "img2": "99",        "img3": "2",        "img4": "99",        "img5": "1",        "img6": "99",        "img7": "8",        "img8": "99",        "img9": "1",        "img10": "99",        "img11": "2",        "img12": "99",        "img_single": "1",        "img_title1": "多云",        "img_title2": "多云",        "img_title3": "阴",        "img_title4": "阴",        "img_title5": "多云",        "img_title6": "多云",        "img_title7": "中雨",        "img_title8": "中雨",        "img_title9": "多云",        "img_title10": "多云",        "img_title11": "阴",        "img_title12": "阴",        "img_title_single": "多云",        "wind1": "微风",        "wind2": "微风",        "wind3": "微风",        "wind4": "东北风3-4级",        "wind5": "微风",        "wind6": "微风",        "fx1": "微风",        "fx2": "微风",        "fl1": "小于3级",        "fl2": "小于3级",        "fl3": "小于3级",        "fl4": "3-4级",        "fl5": "小于3级",        "fl6": "小于3级",        "index": "较舒适",        "index_d": "建议着薄外套、开衫牛仔衫裤等服装。年老体弱者应适当添加衣物，宜着夹克衫、薄毛衣等。",        "index48": "较舒适",        "index48_d": "建议着薄外套、开衫牛仔衫裤等服装。年老体弱者应适当添加衣物，宜着夹克衫、薄毛衣等。",        "index_uv": "最弱",        "index48_uv": "最弱",        "index_xc": "适宜",        "index_tr": "适宜",        "index_co": "舒适",        "st1": "19",        "st2": "13",        "st3": "23",        "st4": "16",        "st5": "24",        "st6": "18",        "index_cl": "适宜",        "index_ls": "适宜",        "index_ag": "不易发"    }}

未来六日天气数据主要参数说明如下表所示：

以上接口是我们做天气预报功能将使用到的接口。

二、微信公众平台开发

1. 需要将城市编码对照表导入到数据库中，以下是SAE导入后截图

2. 将城市名转为城市代码的方法，这将在用户发送城市名的时候调用

 1 function fromNameToCode($name) 2 { 3     $MySQL_host = SAE_MYSQL_HOST_M; 4     $mysql_host_s = SAE_MYSQL_HOST_S; 5     $mysql_port = SAE_MYSQL_PORT; 6     $mysql_user = SAE_MYSQL_USER; 7     $mysql_passWord = SAE_MYSQL_PASS; 8     $mysql_database = SAE_MYSQL_DB; 9 10     $mysql_table = "weather";11     $mysql_state = "SELECT * FROM ".$mysql_table." WHERE `cityName` = '".$name."'";12     13     $con = mysql_connect($mysql_host.':'.$mysql_port, $mysql_user, $mysql_password, true);14     if (!$con){15         die('Could not connect: ' . mysql_error());16     }17     mysql_query("SET NAMES 'UTF8'");18     mysql_select_db($mysql_database, $con);19     $result = mysql_query($mysql_state);20     $cityCode = "";21     while($row = mysql_fetch_array($result))22     {23         $cityCode = $row['cityCode']; 24         break;25     }26     mysql_close($con);27     return $cityCode;28 }

3. 编写接口调用函数，用于向天气网发送cURL请求，获取数据

 1 function httPRequest($url) 2 { 3     $ch = curl_init(); 4     curl_setopt($ch, CURLOPT_URL, $url); 5     curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1); 6     $output = curl_exec($ch); 7     curl_close($ch); 8     if ($output === FALSE){ 9         return "cURL Error: ". curl_error($ch);10     }11     return $output;12 }

4. 编写获取天气数据的函数，这里获取实时天气和未来3日天气，并将返回结果封装成图文信息的数组

 1 function getWeatherInfo($cityName) 2 { 3     $cityCode = fromNameToCode($cityName); 4      5     if ($cityCode == "") 6     { 7         return "错误的城市名或者此城市不在数据库中!"; 8     } 9     10     //获取实时天气11     $url = "http://www.weather.com.cn/data/sk/".$cityCode.".html";12     $output = httpRequest($url);13     $weather = json_decode($output, true); 14     $info = $weather['weatherinfo'];15 16     $weatherArray = array();17     $weatherArray[] = array("Title"=>$info['city']."天气预报", "Description"=>"", "PicUrl"=>"", "Url" =>"");18     if ((int)$cityCode < 101340000){19         $result = "实况 温度：".$info['temp']."℃ 湿度：".$info['SD']." 风速：".$info['WD'].$info['WSE']."级";20         $weatherArray[] = array("Title"=>str_replace("%", "﹪", $result), "Description"=>"", "PicUrl"=>"", "Url" =>"");21     }22 23     //获取六日天气24     $url = "http://m.weather.com.cn/data/".$cityCode.".html";25     $output = httpRequest($url);26     $weather = json_decode($output, true); 27     $info = $weather['weatherinfo'];28 29     if (!empty($info['index_d'])){30         $weatherArray[] = array("Title" =>$info['index_d'], "Description" =>"", "PicUrl" =>"", "Url" =>"");31     }32 33     $weekArray = array("日","一","二","三","四","五","六");34     $maxlength = 3;35     for ($i = 1; $i <= $maxlength; $i++) {36         $offset = strtotime("+".($i-1)." day");37         $subTitle = date("m月d日",$offset)." 周".$weekArray[date('w',$offset)]." ".$info['temp'.$i]." ".$info['weather'.$i]." ".$info['wind'.$i];38         $weatherArray[] = array("Title" =>$subTitle, "Description" =>"", "PicUrl" =>"http://discuz.comli.com/weixin/weather/"."d".sprintf("%02u",$info['img'.(($i *2)-1)]).".jpg", "Url" =>"");39     }40 41     return $weatherArray;42 }

5. 在微信公众平台接口函数中处理收到的文本消息时，文本将为城市名，直接调用获取天气的函数

  1 /*  2     方倍工作室  3     CopyRight 2013 All Rights Reserved  4 */  5   6 define("TOKEN", "weixin");  7   8 $wechatObj = new wechatCallbackapiTest();  9 if (!isset($_GET['echostr'])) { 10     $wechatObj->responseMsg(); 11 }else{ 12     $wechatObj->valid(); 13 } 14  15 class wechatCallbackapiTest 16 { 17     public function valid() 18     { 19         $echoStr = $_GET["echostr"]; 20         if($this->checkSignature()){ 21             echo $echoStr; 22             exit; 23         } 24     } 25  26     private function checkSignature() 27     { 28         $signature = $_GET["signature"]; 29         $timestamp = $_GET["timestamp"]; 30