Golang通过小程序获取微信openid的方法示例

<!--index.wxml-->
<view class="container">
 <button bindtap="onGetOpenId">点击获取openid</button>
</view>

//index.js
Page({
 onGetOpenId() {
  wx.login({
   success: res => {
    if (res.code) {
     wx.request({
      url: "http://localhost:2020/openid",
      method: "POST",
      data: {
       code: res.code
      },
      success: res => {
       console.log(res);
      }
     });
    }
   }
  });
 }
});

package main

import (
  "encoding/json"
  "fmt"
  "net/http"
)

func main() {
  http.HandleFunc("/openid", getOpenID)
  http.ListenAndServe(":2020", nil)
}

func getOpenID(writer http.ResponseWriter, request *http.Request) {
  if request.Method != http.MethodPost {
    return
  }

  var codeMap map[string]string
  err := json.NewDecoder(request.Body).Decode(&codeMap)
  if err != nil {
    return
  }
  defer request.Body.Close()

  code := codeMap["code"]
  openid, err := sendWxAuthAPI(code)
  if err != nil {
    return
  }
  fmt.Println("my openid", openid)
}

const (
  code2sessionURL = "https://api.weixin.qq.com/sns/jscode2session?appid=%s&secret=%s&js_code=%s&grant_type=authorization_code"
  appID      = "你的AppID"
  appSecret    = "你的AppSecret"
)

func sendWxAuthAPI(code string) (string, error) {
  url := fmt.Sprintf(code2sessionURL, appID, appSecret, code)
  resp, err := http.DefaultClient.Get(url)
  if err != nil {
    return "", err
  }
  var wxMap map[string]string
  err = json.NewDecoder(resp.Body).Decode(&wxMap)
  if err != nil {
    return "", err
  }
  defer resp.Body.Close()

  return wxMap["openid"], nil
}