版权声明：本文为 zzwwjjdj1(意外金喜) 原创文章，非商用自由转载-保持署名-注明出处，谢谢。 /zzwwjjdj1/article/details/79351005
微信小程序-获取用户session_key,openid,unionid - 后端为nodejs8.0+
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./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 = '/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：${r.statusCode}`);}return resolve(d);});})}; }; module.exports = Ut;
2、新增路由，appId、secret在小程序的后台获取
router.post("/openid", async (req, res) => { const Ut = require("../common/utils"); try { console.log(req.body); let appId = "wx70xxxxxxbed01b"; let secret = "5ec6exxxxxx49bf161a79dd4"; let { js_code } = req.body; let opts = {url: `https://api./sns/jscode2session?appid=${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：
这个返回结果没有unionid，按照官方的说法，需要在微信开放平台绑定小程序；
如果需要解密和数据校验，请跳转这里。
参考地址：
https://mp./debug/wxadoc/dev/api/api-login.html
https://mp./debug/wxadoc/dev/api/uinionID.html
