2 后端代码的配置

const koa = require("koa");
const router = require("koa-router")();
const app = new koa();
const bodyParser = require("koa-bodyparser");
router.post("/login", async ctx => {
    // username=cheng pass=123
    var {username,pass} = ctx.request.body;
    if (username == "cheng" && pass == "123") {
        ctx.cookies.set("auth", true, {
            httpOnly: false
        })
        ctx.body = {
            auth: true,
            code: 200,
            msg: "登录成功"
        }
    }else{
        ctx.body = {
            code:400,
            msg:"登录失败"
        }
    }
})
app.use(async (ctx, next) => {
    ctx.set("Access-Control-Allow-Methods", "*")
    // 跨域
    ctx.set('Access-Control-Allow-Headers', 'Content-Type, Content-Length, Authorization, Accept, X-Requested-With , yourHeaderFeild');
    ctx.set("Access-Control-Allow-Origin", ctx.headers.origin);
    //允许跨域发送cookie请求
    ctx.set("Access-Control-Allow-Credentials", true)
    if (ctx.method == "OPTIONS") {
        ctx.body = 200
    } else {
        await next();
    }
})
app.use(bodyParser());
app.use(router.routes());
app.listen(8000);