微信小程序如何获取用户session_key,openid,unioni（代码）

互联网 18-9-7

微信小程序中获取用户session_key,openid,unioni，这是小程序中经常可以看到的功能，那么如何实现小程序获取session_key,openid和unionid；本篇文章将给大家介绍关于后端为node.js的微信小程序获取用户session_key,openid,unionid的方法实现。

步骤：

1、通过wx.login接口获取code既jscode，传递到后端；

2、后端请求

https://api.weixin.qq.com/sns/jscode2session?appid=APPID&secret=SECRET&js_code=JSCODE&grant_type=authorization_code

地址，就能获取到openid和unionid。

小程序接口promise化和封装

1、utils文件夹下创建wechat.js文件

/**  * Promise化小程序接口  */ class Wechat {   /**    * 登陆    * @return {Promise}     */   static login() {     return new Promise((resolve, reject) => wx.login({ success: resolve, fail: reject }));   };    /**    * 获取用户信息    * @return {Promise}     */   static getUserInfo() {     return new Promise((resolve, reject) => wx.getUserInfo({ success: resolve, fail: reject }));   };    /**    * 发起网络请求    * @param {string} url      * @param {object} params     * @return {Promise}     */   static request(url, params, method = "GET", type = "json") {     console.log("向后端传递的参数", params);     return new Promise((resolve, reject) => {       let opts = {         url: url,         data: Object.assign({}, params),         method: method,         header: { 'Content-Type': type },         success: resolve,         fail: reject       }       console.log("请求的URL", opts.url);       wx.request(opts);     });   };    /**    * 获取微信数据,传递给后端    */   static getCryptoData() {     let code = "";     return this.login()       .then(data => {         code = data.code;         console.log("login接口获取的code:", code);         return this.getUserInfo();       })       .then(data => {         console.log("getUserInfo接口", data);         let obj = {           js_code: code,         };         return Promise.resolve(obj);       })       .catch(e => {         console.log(e);         return Promise.reject(e);       })   };    /**    * 从后端获取openid    * @param {object} params     */   static getMyOpenid(params) {     let url = 'https://xx.xxxxxx.cn/api/openid';     return this.request(url, params, "POST", "application/x-www-form-urlencoded");   }; } module.exports = Wechat;

2、修改小程序的app.js文件

let wechat = require('./utils/wechat.js'); App({   onLaunch() {     this.getUserInfo();   },   getUserInfo() {     wechat.getCryptoData()       .then(d => {         return wechat.getMyOpenid(d);       })       .then(d => {         console.log("从后端获取的openid", d.data);       })       .catch(e => {         console.log(e);       })   } })

后端nodejs，是用的express命令行生成的项目框架，

1、创建common文件夹，创建utils文件，使用request模块请求接口，promise化request

const request = require("request"); class Ut {      /**      * promise化request      * @param {object} opts       * @return {Promise<[]>}      */     static promiseReq(opts = {}) { 	return new Promise((resolve, reject) => { 	    request(opts, (e, r, d) => { 		if (e) { 		    return reject(e); 		} 	        if (r.statusCode != 200) { 		    return reject(`back statusCode：${r.statusCode}`); 		} 		return resolve(d); 	    }); 	})     };  };  module.exports = Ut;

2、新增路由，appId、secret在小程序的后台获取

router.post("/openid", async (req, res) => {   const Ut = require("../common/utils");   try {     console.log(req.body);     let appId = "wx70xxxxxxbed01b";     let secret = "5ec6exxxxxx49bf161a79dd4";     let { js_code } = req.body;     let opts = {       url: `https://api.weixin.qq.com/sns/jscode2session?appid=${appId}&secret=${secret}&js_code=${js_code}&grant_type=authorization_code`     }     let r1 = await Ut.promiseReq(opts);     r1 = JSON.parse(r1);     console.log(r1);     res.json(r1);   }   catch (e) {     console.log(e);     res.json('');   } })

结果：