feat(jsSdk): Add jsSdk Function

Author: lei3265018

Diff for: README.md

@@ -42,6 +42,6 @@
 - [ ] 网址缩短
 - [ ] 语义查询
 - [ ] 数据分析
-- [ ] JSSDK服务端支持
+- [x] JSSDK服务端支持
 - [ ] 素材管理
 - [ ] 摇一摇周边

Diff for: src/modules/sdk/wechat.sdk.ts

@@ -0,0 +1,76 @@
+import { WeChatUtil } from '../../utile/wechat.util';
+import { CACHE_MANAGER, HttpException, HttpService, Inject, Injectable } from '@nestjs/common';
+import * as crypto from 'crypto';
+
+@Injectable()
+export class WechatSdk {
+  constructor(
+    @Inject(WeChatUtil) private readonly wechatUtil: WeChatUtil,
+    @Inject(HttpService) private readonly httpService: HttpService,
+    @Inject(CACHE_MANAGER) protected readonly cacheManager: any,
+  ) {}
+
+  /**
+   * sdk 签名算法
+   * @param {string} appid （必传）用于取 jsapi_ticket
+   * @param {string} url （必传） 用于签名的url，注意必须与调用JSAPI时的页面URL完全一致
+   * @returns {Promise<string>}
+   * 注意事项:
+   * 1.签名用的noncestr和timestamp必须与wx.config中的nonceStr和timestamp相同。
+   * 2.签名用的url必须是调用JS接口页面的完整URL。
+   * 详情请参开微信公众平台js-sdk附录一，https://mp.weixin.qq.com/wiki?t=resource/res_main&id=mp1421141115
+   */
+  async signatureAlgorithm (nonceStr: string, timestamp: string, appid: string, url: string) {
+    const ticket = await this.getTicket(appid);
+    const ret = { jsapi_ticket: ticket, nonceStr,  timestamp, url};
+    const str = await this.wechatUtil.sortQuery(ret);
+    const shasum = crypto.createHash('sha1');
+    shasum.update(str);
+    return shasum.digest('hex');
+  }
+
+  /**
+   * 获取jsapi_ticket
+   * jsapi_ticket是公众号用于调用微信JS接口的临时票据。
+   * 正常情况下，jsapi_ticket的有效期为7200秒，通过access_token来获取。
+   * 由于获取jsapi_ticket的api调用次数非常有限，频繁刷新jsapi_ticket会导致api调用受限，影响自身业务，开发者必须在自己的服务全局缓存jsapi_ticket 。
+   * @param {string} appid （必传） 用于存jsapi_ticket
+   * @returns {Promise<any>}
+   */
+  async getTicket(appid: string) {
+    if (!appid) {
+      throw new HttpException('appid不存在！！', 500);
+    }
+    const ticket = await this.cacheManager.get(appid);
+    if (ticket) {
+      return ticket;
+    }
+    const accessToken: string = await this.wechatUtil.ensureAccessToken(appid);
+    const url = `https://api.weixin.qq.com/cgi-bin/ticket/getticket?access_token=${accessToken}&type=jsapi`;
+    const { data } = await this.httpService.get(url).toPromise();
+    if (data.errcode) {
+      throw new HttpException(data.errmsg, data.errcode);
+    }
+    await this.cacheManager.set(appid, data.data.ticket);
+    return ticket;
+  }
+
+  /**
+   * 获取JsSdk wx.config接口所需的参数
+   * @param {string} appid （必传）
+   * @param {string} url （必传） 用于签名的url，注意必须与调用JSAPI时的页面URL完全一致
+   * @returns {Promise<{nonceStr: any; timestamp: string; signature: string}>}
+   */
+  async getJsSdkConfig(appid: string, url: string) {
+    if (!appid) {
+      throw new HttpException('appid不存在！！', 500);
+    }
+    if (!url) {
+      throw new HttpException('url不存在！！', 500);
+    }
+    const nonceStr = await this.wechatUtil.generatingRandomNumbers();
+    const timestamp = await this.wechatUtil.generationTimestamp();
+    const signature = await this.signatureAlgorithm(nonceStr, timestamp, appid, url);
+    return {nonceStr, timestamp, signature};
+  }
+}