准备工作

• 登录微信公众平台 -> 功能 -> 订阅消息 -> 对里面的模板进行选用或者自定义
  
• 需要在前端小程序端调起消息订阅接口，官方地址：
  https://developers.weixin.qq.com/miniprogram/dev/api/open-api/subscribe-message/wx.requestSubscribeMessage.html
• 服务端发送消息到服务通知 模板id需要给到后台，后台来进行发出消息，官方文档地址：
  https://developers.weixin.qq.com/miniprogram/dev/api-backend/open-api/subscribe-message/subscribeMessage.send.html

演示

给按钮绑定一个事件触发订阅消息接口,示例如下：
wxml

<van-button round type="info" bindtap="pass" >通过</van-button>

js

  pass:function(){
    wx.requestSubscribeMessage({
      tmplIds: [\'模板ID\'],
      success:(res)=> {  
        //成功回调  
          wx.setStorageSync(\'tmplid\', \'模板ID\')
        },

      fail(err) {

      }
  })
    wx.navigateTo({
      url: \'/pages/test/pass\'
    })
  }

点击按钮

选择允许，再点击发送订阅消息，会在服务通知收到一条订阅消息

后端代码(以原生PHP为例)

<?php
ini_set(\'display_errors\', \'On\');
$token_file = \'./mn_access_token\';
$life_time = 7200;
//文件存在，并且最后修改时间与当前时间的差小于access_token的有效期，则有
if(file_exists($token_file) && time()-filemtime($token_file)<$life_time){
   //直接获取
  $access_token = file_get_contents($token_file);
}else{
  $appid = \'你的appid\';
  $secret =\'你的appsecret\';
  $url = "https://api.weixin.qq.com/cgi-bin/token?grant_type=client_credential&appid=$appid&secret=$secret";
  $curl = curl_init();
  curl_setopt($curl, CURLOPT_RETURNTRANSFER, true);
  curl_setopt($curl, CURLOPT_TIMEOUT, 500);
  curl_setopt($curl, CURLOPT_SSL_VERIFYPEER, false);
  curl_setopt($curl, CURLOPT_SSL_VERIFYHOST, false);
  curl_setopt($curl, CURLOPT_URL, $url);
  $res = curl_exec($curl);
  curl_close($curl);
  $tokenArr = json_decode($res,true);
  $access_token = $tokenArr[\'access_token\'];
  file_put_contents($token_file, $access_token);
}
  $msgUrl = "https://api.weixin.qq.com/cgi-bin/message/subscribe/send?access_token=".$access_token;
  $data = [
  \'touser\' => $_POST[\'openid\'],
  \'template_id\' => $_POST[\'tplid\'],
  \'page\' => \'/pages/doctor/borrowcheckpass\',
  \'data\' =>
  [
    \'number4\' =>
    [
      \'value\' => date(\'Ymd\').substr(implode(NULL, array_map(\'ord\', str_split(substr(uniqid(), 7, 13), 1))), 0, 8),
    ],
    \'name6\' =>
    [
      \'value\' => \'测试患者\',
    ],
    \'thing8\' =>
    [
      \'value\' => \'测试实物玻片\',
    ],
    \'phone_number7\' =>
    [
      \'value\' => \'0551-\'.mt_rand(1000000,9999999),
    ],
    \'amount2\' =>[
       \'value\' =>mt_rand(1,100),
    ]
  ],
];
  $ch = curl_init();

  curl_setopt($ch, CURLOPT_URL, $msgUrl);

  curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);

  curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, FALSE);

  curl_setopt($ch, CURLOPT_SSL_VERIFYHOST, FALSE);

  // POST数据

  curl_setopt($ch, CURLOPT_POST, 1);

  // 把post的变量加上

  curl_setopt($ch, CURLOPT_POSTFIELDS, json_encode($data));

  $output = curl_exec($ch);

  curl_close($ch);
  echo $output;

其中data参数格式可以模板详情