节点我的应用程序如何找到index.js

Question

Folder structure

• bin - www.js

• lib - jsFiles...

• models - jsFiles...

• node_modules -Folders and Files

• public - index.html

• route - jsFiles...

• index.js

• package.json

I use Express, angular.js. Server starts at www.js and It calls index.js. After that, When I type merely "localhost:3000" It shows me public/index.html. I don't have route for '/' but It shows me 'public/index.html'. I can not understand this. Please let me know about the process.

www.js

var debug = require('debug')('example-server');
var app = require(process.cwd()+'/index');

//listen at 3000 port
app.set('port',process.env.PORT || 3000);


var server = app.listen(app.get('port'),function()
{
    debug('Express server listening on port ' + server.address().port);
});

index.js

var favicon      = require('serve-favicon');
var express      = require('express');
var path         = require('path');
var logger       = require('morgan');
var cookieParser = require('cookie-parser');
var bodyParser   = require('body-parser');
//Connection for DB
require('./lib/connection');
var employees    = require('./routes/employees');
var teams        = require('./routes/teams');
var app = express();

// Writing at routing table
app.use(favicon(__dirname + '/public/favicon.ico'));
app.use(logger('dev'));
app.use(bodyParser.json());
app.use(bodyParser.urlencoded({ extended:true }));
app.use(cookieParser());
app.use(express.static(path.join(__dirname,'public')));

app.use(employees);
app.use(teams);


// send 404 to errorhandler
app.use(function(err,req,res,next)
{
    var err = new Error('Not Found');
    err.status = 404;
    console.log(error);
    next(error);
});

...
...
module.exports = app;

Answer 1

将相对路径放置到文件夹（在层次结构中向上）。

var app = require('../index');

Answer 2

In express.js the sequence in which you register your middleware makes a huge difference.

When express.js receives a request, it starts from top and executes registered middleware.

Middlewares are registered in express app using app.use(middleware_goes_here) this type of middleware gets executed no matter what the request url is on the other hand you can also register a middleware like app.use('/url/path',middleware_goes_here) in this case we are registering this middleware to '/url/path' so this middleware will only get executed when you visit '/url/path' (and non of the previous matching middleware serves the request without calling next() )

This app.use(express.static(path.join(__dirname,'public'))); line of code does the magic.

You can go here (express.static ref) to know more about static content serving and routing.

Basically what happens is, we are configuring express.static middleware to serve static content "as is" from "public" folder. So when you make any request and it matches a static content in public folder, then it will serve it otherwise express.static will call next middleware in sequence.

So in your case, the first middleware that actually server input request is express.static without any route filters, so it servers index.html even without a specifically defined route. If your public folder had file at public/javascript/jquery.js then following url will map to it http://localhost:3000/javascript/jquery.js

NOTE: You do not have to specify "public" in the url, the way in which express.static is registered, it will server contents FROM "public" folder.

................

UPDATE: How does default work in express.static ?

By default, app.use(express.static(path.join(__dirname,'public'))); this will take index.html as default document. If you want to set index2.html as your default document, you can do that by doing something like this app.use(express.static(path.join(__dirname,'public'),{index: 'index2.html'}));

Hope it helps.