微信获取 Token 功能实现

+'use strict';
+
+/*
+ * 生成微信分享所需的签名
+ * bikai <kai.bi@yoho.cn>
+ * 2016.6.15
+ */
 const request = require('request-promise');
 const Promise = require('bluebird');
+const crypto = require('crypto');
 const logger = require('../../../library/logger');
+const cache = require('../../../library/cache');
+
+const appId = 'wx75e5a7c0c88e45c2';
+const secret = 'ce21ae4a3f93852279175a167e54509b';
+
+const sha1 = (etr) => {
+    const generator = crypto.createHash('sha1');
+
+    generator.update(etr);
+    return generator.digest('hex');
+};
+
+const accessTokenCacheKey = 'wechatShare:accessToken';
+const ticketCacheKey = 'wechatShare:ticket';
 
-const appId = '';
-const secret = '';
+// 微信 JS 接口签名校验工具 http://mp.weixin.qq.com/debug/cgi-bin/sandbox?t=jsapisign
 
 const wechat = {
     getAccessToken: Promise.coroutine(function* () {
+        let accessToken = yield cache.get(accessTokenCacheKey);
+
+        if (accessToken) {
+            return accessToken;
+        }
+
+        logger.info('调用微信 API 获取 accessToken');
         return request({
             url: 'https://api.weixin.qq.com/cgi-bin/token',
             qs: {
                 grant_type: 'client_credential',
                 appid: appId,
                 secret: secret
-            }
+            },
+            json: true
+        }).then((res) => {
+
+            // accessToken 有效期 7200s，缓存 7100s
+            cache.set(accessTokenCacheKey, res.access_token, 7100).catch((err) => {
+                logger.error('微信分享 Token, 缓存 accessToken 时出错', JSON.stringify(err));
+            });
+            return res.access_token;
         }).catch((err) => {
             logger.error('微信分享 Token, 获取 accessToken 时出错', JSON.stringify(err));
         });
     }),
 
     getTicket: Promise.coroutine(function* (accessToken) {
+        let ticket = yield cache.get(ticketCacheKey);
+
+        if (ticket) {
+            return ticket;
+        }
+
+        logger.info('调用微信 API 获取 ticket');
         return request({
             url: 'https://api.weixin.qq.com/cgi-bin/ticket/getticket',
             qs: {
                 access_token: accessToken,
                 type: 'jsapi'
-            }
+            },
+            json: true
+        }).then(res => {
+
+            // ticket 有效期 7200s，缓存 7100s
+            cache.set(ticketCacheKey, res.ticket, 7100).catch((err) => {
+                logger.error('微信分享 Token, 缓存 ticket 时出错', JSON.stringify(err));
+            });
+            return res.ticket;
         }).catch((err) => {
             logger.error('微信分享 Token, 获取 ticket 时出错', JSON.stringify(err));
         });
     }),
 
-    calcSignature: Promise.coroutine(function* () {
-        return yield Promise.resolve(true);
+    calcSignature: Promise.coroutine(function* (data) {
+        let accessToken = yield this.getAccessToken();
+
+        data = Object.assign({
+            noncestr: Math.random().toString(36).substr(2, 15),
+            timestamp: Math.floor(Date.now() / 1000) + '',
+            ticket: yield this.getTicket(accessToken)
+        }, data);
+        const str = `jsapi_ticket=${data.ticket}&noncestr=${data.noncestr}&timestamp=${data.timestamp}&url=${data.url}`;
+
+        return sha1(str);
     })
 };
 
+// 测试
+// wechat.calcSignature({
+//     url: 'http://www.yohobuy.com/boys'
+// }).then(console.log);
+
 module.exports = wechat;