Question

我在express.Router（）中添加中间件时遇到问题。

    let router = express.Router();

    let mid = function(req, res, next) {
        console.log("mid");
        next();
    }

    router.get("/", function(req, res) {
        res.send("public");
    })

    let userRouter = express.Router();

    userRouter.use(mid);

    userRouter.get("/users", function(req,res) {
        res.send("users");
    })

    router.use(userRouter);

    app.use("/", router);

    router = express.Router();

    router.get("/", function(req, res) {
        res.send("api");
    })

    app.use("/api", router);

以下是结果：

访问＆＃34; /＆＃34;不要触发中间件。访问＆＃34; / users＆＃34;触发中间件。访问＆＃34; / api＆＃34;触发中间件。

我不明白为什么＆＃34; / api＆＃34;正在触发中间件。

Answer 1

检查Express documentation for router middleware。

Express API documentation也可能有用。

我组织了一些代码，现在它可以正常工作了。

'use strict';
let express = require('express');
let expressApp = express();

// --- middleware function ---
let usersMiddleware = function(req, res, next) {
    console.log("users router middleware");
    next();
}

// --- middleware function ---
let appMiddleware = function(req, res, next) {
    console.log("app middleware");
    next();
}

// --- public router ---
let publicRouter = express.Router();
publicRouter.get("/", function(req, res) {
    res.send("public");
});

// --- user router ---
let userRouter = express.Router();
// --- this is a router based middleware, 
// --- to be used only for this router ---
userRouter.use(usersMiddleware);
userRouter.get("/", function(req,res) {
    res.send("users");
});

// --- api router ---
let apiRouter = express.Router();
apiRouter.get("/", function(req, res) {
    res.send("api");
});

// --- this is a app based middleware, 
// --- it will be used for every route of the app after this line
expressApp.use(appMiddleware); 

// --- adding the routers to the app ---
expressApp.use("/", publicRouter);
expressApp.use("/users", userRouter);
expressApp.use("/api", apiRouter);

expressApp.listen(8080);

请注意，此处使用了两种中间件，一种连接到特定路由器（即您想要的路由器），另一种连接到应用，用于所有其他路由（我添加了此一个显示差异）。

/api触发了中间件，因为您将其添加到app而不是路由器实例。

Express中间件在添加后作用于每个路由器

1 个答案: