app.js

const Koa = require('koa');
const static = require('koa-static');
const { koaBody } = require('koa-body');
const { koaSwagger } = require('koa2-swagger-ui');
const myConfig = require("./config");
const path = require("path");
const system = require("./Core/System");
const router = require('./Controller/router');
const EventManager = require("./Core/EventManager");

const app = new Koa();

// 使用koa-body中间件解析请求体
app.use(koaBody({
    multipart: true,        //解释多个文件
    formLimit: '50mb',
    jsonLimit: '50mb',
    textLimit: '50mb',
}));

//swagger-文档中间件
app.use(koaSwagger({
    routePrefix: '/swagger', // api文档访问地址
    swaggerOptions: {
        url: '/swagger.json', // example path to json
    }
}));

// process.on('unhandledRejection', (reason, promise) => {     //全局监听Promise未捕获的Rejection
//     em.emit("Debug.Log", reason, "unhandledRejection", reason, promise); 
// });
app.on("error", (err, ctx) => {
    if (ctx) CtxSetAllowHead(ctx);  //处理500错误到前端时会有跨域拦截
    let em = new EventManager();
    em.emit("Debug.Log", err?.message || err, "KOAERR", err);
});

//设置跨域
app.use(async (ctx, next) => {
    CtxSetAllowHead(ctx);
    await next();
});

//注册路由
app.use(router.routes());
//启动静态文件服务
let filePath = path.join(myConfig.dataPath, "");
console.log("静态文件服务路径:\t\t", path.resolve(filePath));
app.use(static(filePath));

//app.use(Router.allowedMethods()); TODO: 推荐的处理错误请求方式

system.then((service) => {
    console.log("开始监听：8777");
    let server = app.listen(8777);
    new service.io(server);
});


/**
 * 统一设置的上下文，解决跨域拦截
 * @param {*} ctx 
 */
function CtxSetAllowHead(ctx) {
    ctx.set("Access-Control-Allow-Origin", "*");
    ctx.set("Access-Control-Allow-Methods", "OPTIONS, GET, PUT, POST, DELETE, PATCH");
    ctx.set("Access-Control-Allow-Headers", "Content-Type,Access-Token,Authorization,Accept,Origin,X-Requested-With,Accept-Language,Content-Language");
    ctx.set("Access-Control-Allow-Credentials", true);
    if (ctx.request.method === 'OPTIONS') { // 直接响应数据 应对axios的跨域探测
        ctx.status = 200;
    }
}