node.js — koa — Typescript 微信连接api

node.js — koa — Typescript 微信连接api

服务器中间层框架为koa，使用node原生的加密方式，应该整个公司项目的微信api都从一个接口上出去，不应该分散到各个项目去单独调api，便于管理维护，减少调用次数

memory-cache为请求到的access_token做缓存，微信调用access_token每日有次数限制。目前是根据时间判断的，理应后期加上定时任务

1. 获取access_token存入缓存，有效期两小时，有的话从缓存中取
2. 获取ticket存入缓存，有效期两小时，有的话从缓存中取
3. 将获取到的ticket和其他三个参数进行sha1-HEX加密，拿到签名signature
4. 提供一个接口供前端调(ps: 敏感字段请勿传给前台)

import * as koa from "koa";
import { HTTPProtocol } from "@Constance/interface"

import { getData, httpType } from '@Utils/http'
import Config from '@Config/config'
import * as cache from 'memory-cache'
const crypto = require('crypto');

interface IAccessTokenResponse {
	errcode: number;
	errmsg: string;
	access_token: string;
	expires_in: number;
}
interface jsAPITicketResponse {
	errcode: number;
	errmsg: string;
	ticket: string;
	expires_in: number;
}

const getWxConfig = async (ctx: koa.Context) => {


	const { url } = ctx.query

	// 返回给前台的数据
	let res: HTTPProtocol<any> = {
		code: 0,
		msg: "成功",
		data: ""
	}

	if (!url) {
		res.msg = "无URL"
		ctx.body = res
		return;
	}



	let timestamp: number = Math.floor(Date.now() / 1000);

	// 获取access_token 
	if (!cache.get("tokenObj") || cache.get("tokenObj").expires_in < timestamp || cache.get("tokenObj").app_id !== Config.wx_gzh.app_id) {

		let getAccessURL = Config.wx_gzh.access_token + `&appid=` + Config.wx_gzh.app_id + `&secret=` + Config.wx_gzh.app_secret

		const WxAccessToken = await getData<IAccessTokenResponse>(getAccessURL, httpType.get)

		if (WxAccessToken && WxAccessToken.access_token) {
			cache.put("tokenObj", {
				access_token: WxAccessToken.access_token,
				expires_in: timestamp + (WxAccessToken.expires_in - 1800),
				app_id: Config.wx_gzh.app_id
			}, 1.5 * 60 * 60 * 1000)
		} else {
			cache.put("tokenObj", null);
			ctx.logger.error(new Error(`wxconfig: ${JSON.stringify(Config.wx_gzh)}`));
			ctx.logger.error(new Error(`tokenResult: ${JSON.stringify(WxAccessToken)}`));
		}
	}

	res.code = 500
	res.msg = "获取access失败"


	// 获取ticket
	if (cache.get("tokenObj") && cache.get("tokenObj").app_id === Config.wx_gzh.app_id) {
		timestamp = Math.floor(Date.now() / 1000);
		if (!cache.get("jsapiObj") || cache.get("jsapiObj").expires_in < timestamp || cache.get("jsapiObj").app_id !== Config.wx_gzh.app_id) {

			let getTicketURL = Config.wx_gzh.js_api + `&access_token=` + cache.get("tokenObj").access_token
			const WxTicket = await getData<jsAPITicketResponse>(getTicketURL, httpType.get)

			if (WxTicket && WxTicket.ticket) {
				cache.put("jsapiObj", {
					ticket: WxTicket.ticket,
					expires_in: timestamp + (WxTicket.expires_in - 1800),
					app_id: Config.wx_gzh.app_id
				}, 1.5 * 60 * 60 * 1000)
			} else {
				cache.put("jsapiObj", null);
				ctx.logger.error(new Error(`wxconfig: ${JSON.stringify(Config.wx_gzh)}`));
				ctx.logger.error(new Error(`jsapiResult: ${JSON.stringify(WxTicket)}`));
			}
		}
		if (cache.get("jsapiObj") && cache.get("jsapiObj").app_id === Config.wx_gzh.app_id) {

			const jsapi_ticket = cache.get("jsapiObj").ticket;
			const nonceStr = Config.wx_gzh.nonce_str
			timestamp = Math.floor(Date.now() / 1000);
			const string1 = `jsapi_ticket=${jsapi_ticket}&noncestr=${nonceStr}&timestamp=${timestamp}&url=${url}`;
			const signature = sha1Trans(string1)
			res.code = 0
			res.msg = "成功"
			res.data = {
				nonceStr: nonceStr,
				timestamp: timestamp,
				signature: signature,
				appId: Config.wx_gzh.app_id
			};
		}
	}

	function sha1Trans(str: string) {
		var sha1 = crypto.createHash('sha1');//创建哈希加密算法，后边可以是md5，sha1,sha256等
		var newStr = sha1.update(str).digest('HEX');
		return newStr
	}

	ctx.body = res

};

export {
	getWxConfig
}

配置文件为：

"wx_gzh": {
   "nonce_str": "随机字符串",
   "app_id": "你自己的",
   "app_secret": "你自己的",
   "js_api": "https://api.weixin.qq.com/cgi-bin/ticket/getticket?type=jsapi",
   "access_token": "https://api.weixin.qq.com/cgi-bin/token?grant_type=client_credential"
 }