From 07450e6864972696bf720347dedfa5c2a1bd46f1 Mon Sep 17 00:00:00 2001
From: xialvjun <xialvjun@live.com>
Date: Fri, 19 Apr 2019 16:05:37 +0800
Subject: [PATCH] support miniprogram like wechat-oauth

---
 lib/oauth.js | 108 ++++++++++++++++++++++++++++++++++++++++++++++++---
 package.json |   3 +-
 2 files changed, 105 insertions(+), 6 deletions(-)

diff --git a/lib/oauth.js b/lib/oauth.js
index ff57565..d0fa68e 100644
--- a/lib/oauth.js
+++ b/lib/oauth.js
@@ -4,6 +4,9 @@ const httpx = require('httpx');
 
 const querystring = require('querystring');
 
+
+const WxBizDataCrypt = require('wechat-oauth/lib/wx_biz_data_crypt');
+
 class AccessToken {
   constructor(data) {
     this.data = data;
@@ -39,11 +42,13 @@ class AccessToken {
  * @param {String} appsecret 在公众平台上申请得到的app secret
  * @param {Generator} getToken 用于获取token的方法
  * @param {Generator} saveToken 用于保存token的方法
+ * @param {Boolean} isMiniProgram 是否是微信小程序
  */
 class OAuth {
-  constructor(appid, appsecret, getToken, saveToken) {
+  constructor(appid, appsecret, getToken, saveToken, isMiniProgram) {
     this.appid = appid;
     this.appsecret = appsecret;
+    this.isMiniProgram = isMiniProgram;
     // token的获取和存储
     this.store = {};
     this.getToken = getToken || async function (openid) {
@@ -201,6 +206,47 @@ class OAuth {
     return this.processToken(data);
   }
 
+  /**
+   * 根据授权获取到的code，换取小程序的session key和openid（以及有条件下的unionid）
+   * 获取openid之后，可以调用`wechat.API`来获取更多信息
+   * Examples:
+   * ```
+   * await api.getSessionKey(code);
+   * ```
+   * Exception:
+   *
+   * - `err`, 获取session key出现异常时的异常对象
+   *
+   * 返回值:
+   * ```
+   * {
+   *  data: {
+   *    "session_key": "SESSION_KEY",
+   *    "openid": "OPENID",
+   *    "unionid": "UNIONID"
+   *  }
+   * }
+   * ```
+   * @param {String} code 授权获取到的code
+   */
+  async getSessionKey(code) {
+    var info = {
+      appid: this.appid,
+      secret: this.appsecret,
+      js_code: code,
+      grant_type: 'authorization_code',
+    };
+
+    var url = `https://api.weixin.qq.com/sns/jscode2session?${querystring.stringify(info)}`;
+    var data = await this.request(url, {
+      headers: {
+        accept: 'application/json'
+      }
+    });
+
+    return this.processToken(data);
+  }
+
   /**
    * 根据refresh token，刷新access token，调用getAccessToken后才有效
    * Examples:
@@ -262,6 +308,39 @@ class OAuth {
     });
   }
 
+  /**
+   * 根据服务器保存的sessionKey对从小程序客户端获取的加密用户数据进行解密
+   * Examples:
+   * ```
+   * api.decryptMiniProgramUser({encryptedData, iv});
+   * ```
+   * 返回值:
+   * ```
+   *{
+   *    "openId": "OPENID",
+   *    "nickName": "NICKNAME",
+   *    "gender": "GENDER",
+   *    "city": "CITY",
+   *    "province": "PROVINCE",
+   *    "country": "COUNTRY",
+   *    "avatarUrl": "AVATARURL",
+   *    "unionId": "UNIONID",
+   *    "watermark":
+   *    {
+   *        "appid":"APPID",
+   *        "timestamp":TIMESTAMP
+   *    }
+   *}
+  * ```
+  * @param {Object} options 需要解密的对象
+  * @param {String} options.encryptedData 从小程序中获得的加密过的字符串
+  * @param {String} options.iv 从小程序中获得的加密算法初始向量
+  */
+  decryptMiniProgramUser(options) {
+    var decrypter = new WxBizDataCrypt(this.appid, options.sessionKey);
+    return decrypter.decryptData(options.encryptedData, options.iv);
+  }
+
   /**
    * 根据openid，获取用户信息。
    * 当access token无效时，自动通过refresh token获取新的access token。然后再获取用户信息
@@ -368,11 +447,30 @@ class OAuth {
    *  ]
    * }
    * ```
-   * @param {String} code 授权获取到的code
+   * @param {Object|String} options 授权获取到的code
    */
-  async getUserByCode(code) {
-    var token = await this.getAccessToken(code);
-    return this.getUser(token.data.openid);
+  async getUserByCode(options) {
+    var lang, code;
+    if (typeof options === 'string') {
+      code = options;
+    } else {
+      lang = options.lang;
+      code = options.code;
+    }
+
+    if (this.isMiniProgram) {
+      var result = await this.getSessionKey(code);
+      var sessionKey = result.data.session_key;
+      return this.decryptMiniProgramUser({
+        sessionKey,
+        encryptedData: options.encryptedData,
+        iv: options.iv,
+      });
+    } else {
+      var result = this.getAccessToken(code);
+      var openid = result.data.openid;
+      return this.getUser({openid: openid, lang: lang});
+    }
   }
 }
 
diff --git a/package.json b/package.json
index 9915556..f97c504 100644
--- a/package.json
+++ b/package.json
@@ -15,7 +15,8 @@
     "wechat"
   ],
   "dependencies": {
-    "httpx": "^2.1.1"
+    "httpx": "^2.1.1",
+    "wechat-oauth": "^1.5.0"
   },
   "devDependencies": {
     "coveralls": "*",