ExpressJS应用程序(ExpressJS app.use)

ExpressJS应用程序(ExpressJS app.use)

我在学习ExpressJS，并且遇到了这段代码。 我似乎无法理解app.use函数，并且文档对我来说还不清楚。 当app.use被调用时，这个特定示例代码中/ public目录发生了什么？

// Require dependencies var express = require('express'); var app = express(); // Set server port app.set('port', (process.env.PORT || 3000)); // Set static page directory, /public app.use(express.static(__dirname + '/public')); app.use('/public', express.static('public')); // Set template file directory, /views. Set view engine to EJS app.set('views', __dirname + '/views'); app.set('view engine', 'ejs'); // Route root request to pages/index app.get('/', function(request, response) { response.render('pages/index'); }); // Route favicon request to public/favicons app.get('/favicon.ico', function(request, response) { response.render('./public/favicons'); }); // Begin listening at specified port app.listen(app.get('port'), function() { console.log('Node app is running on port', app.get('port')); });

I'm trying to learn ExpressJS and I came across this piece of code. I just can't seem to understand the app.use function and the documentation is unclear to me. What exactly is happening to the /public directory in this particular example code when app.use is called?

// Require dependencies var express = require('express'); var app = express(); // Set server port app.set('port', (process.env.PORT || 3000)); // Set static page directory, /public app.use(express.static(__dirname + '/public')); app.use('/public', express.static('public')); // Set template file directory, /views. Set view engine to EJS app.set('views', __dirname + '/views'); app.set('view engine', 'ejs'); // Route root request to pages/index app.get('/', function(request, response) { response.render('pages/index'); }); // Route favicon request to public/favicons app.get('/favicon.ico', function(request, response) { response.render('./public/favicons'); }); // Begin listening at specified port app.listen(app.get('port'), function() { console.log('Node app is running on port', app.get('port')); });

最满意答案

这很简单 - 你设置的公共目录可以通过HTTP访问。

所以，像http://localhost:3000/public/abc.jpg这样的东西会给你公用文件夹中的abc.jpg 。

该

app.use('/public', express.static('public'))

线意味着 - 匹配任何以/public开头的路径，如：

http://localhost/public/*.jpg

或任何其他扩展名 - 将从public选择该文件（ express.static('public') ）文件夹中的参数并提供该文件。

该线

app.use(express.static(__dirname + '/public'))

意思是 - 匹配任何路径，如果在public目录中找到文件，则通过HTTP提供。

你可以使用这两行 - 不同之处在于URL中的/public部分。

这些文档非常清楚： https ： //expressjs.com/en/starter/static-files.html

It's simple - you are setting up the public directory to be accessible over HTTP.

So, something like http://localhost:3000/public/abc.jpg will give you the abc.jpg from the public folder.

The

app.use('/public', express.static('public'))

line simply means - match any path that starts with /public like:

http://localhost/public/*.jpg

or any other extension - will choose that file from your public (the argument in express.static('public')) folder and serve it.

The line

app.use(express.static(__dirname + '/public'))

means - match any path and if file found in public directory, serve it over HTTP.

You can just use of the these two lines - difference being the /public part in the URL.

The docs are quite clear about this: https://expressjs.com/en/starter/static-files.html