javascript - Node.js 将参数传递给express.js/passport.js 中的 require 函数？明白为什么吗？

Question

大家好，我需要一些帮助来理解 node.js 语法。应用程序已将参数放在需要另一个文件(而不是模块)的路径的 require 函数上。让我给你一个我正在讨论的语法示例，该语法位于名为 server.js 的主 javascript 文件中。

require('./config/passport')(passport);

和

require('./app/routes.js')(app, passport);

我需要知道为什么这些“app”和“passport”参数被传递给我的 require 函数。 app是express，passport是 Passport 模块。

完整的相关文件如下。干杯

var express = require('express');
var app = express();
var port = process.env.PORT || 8080;
var mongoose = require('mongoose');
var passport = require('passport');
var flash = require('connect-flash');
require('./app/models/user');

var morgan = require('morgan');
var cookieParser = require('cookie-parser');
var bodyParser = require('body-parser');
var session = require('express-session');

var configDB = require('./config/database.js');

mongoose.connect(configDB.url);

require('./config/passport')(passport);

app.use(morgan('dev')); //http request logger
app.use(cookieParser()); //reads cookies (needed for authentication)
app.use(bodyParser()); //gets information from html forms

app.set('view engine', 'ejs');

//required for passport
app.use(session({secret: 'jonathanisawesome'}));
app.use(passport.initialize());
app.use(passport.session()); //persistent login sessions
app.use(flash()); //connect-flash for flash messages stored in sessions


//routes
require('./app/routes.js')(app, passport); //loads our routes and passes in our app and fully configured passport

app.listen(port);
console.log('the magix happens on port ' + port);

app.get('/logout', function(req,res){
	req.logout();
	res.redirect('/');
});




//processing of the form
app.post('/login', passport.authenticate('local-login', {
	successRedirect: '/profile',
	failureRedirect: '/login',
	failureFlash : true
}));



app.post('/signup', passport.authenticate('local-signup', {

	successRedirect: '/profile',
	failureRedirect: '/signup',
	failureFlash : true
}));


  // route for facebook authentication and login
    app.get('/auth/facebook', passport.authenticate('facebook', { scope : 'email' }));

    // handle the callback after facebook has authenticated the user
    app.get('/auth/facebook/callback',
        passport.authenticate('facebook', {
            successRedirect : '/profile',
            failureRedirect : '/'
        }));

     app.get('/auth/google', passport.authenticate('google', { scope : ['profile', 'email'] }));

    // the callback after google has authenticated the user
    app.get('/auth/google/callback',
            passport.authenticate('google', {
                    successRedirect : '/profile',
                    failureRedirect : '/'
            }));


    

};



//route middleware to make sure a user is logged in
function isLoggedIn(req,res,next){
	//if user is authenticated in the session, carry on
	if(req.isAuthenticated())
		return next();

	//if they are not, redirect them to the homepage
	res.redirect('/');
};

var LocalStrategy = require('passport-local').Strategy;
var FacebookStrategy = require('passport-facebook').Strategy;
var GoogleStrategy = require('passport-google-oauth').OAuth2Strategy;
var User = require('mongoose').model('User');
var configAuth = require('./auth');
var crypto = require('crypto');
module.exports = function(passport){
	//passport session setup
	//persistent login sessions
	//passport needs ability to serialize and unserialize users out of sessions


	//use to serialize the user for the session
	passport.serializeUser(function(user,done){
		done(null, user.id);
	});


	//deserialize user
	passport.deserializeUser(function(id,done){
		User.findById(id, function(err, user){
			done(err, user);
		});
	});

	//local signup
	//using named strategies one for login and one for signup
	//by default if there was no name it would be called 'local'

    passport.use('local-signup', new LocalStrategy({
        // by default, local strategy uses username and password, we will override with email
        usernameField : 'email',
        passwordField : 'password',
        passReqToCallback : true // allows us to pass back the entire request to the callback
    },
    function(req, email, password, done) {

        // asynchronous
        // User.findOne wont fire unless data is sent back
        process.nextTick(function() {

        
                // create the user
                var newUser = new User();

                // set the user's local credentials
                newUser.email    = email;
                newUser.password = password; //password is hashed on the model layer

                // save the user
                newUser.save(function(err,user) {
				if(err || !user){
				
				//error handling
				
				if(err.code===11000){ //email taken
					return done(null, false, req.flash('signupMessage', 'Sorry, the email '+newUser.email+' has been taken'));
				}else{ //its a hacker
					return done(null, false, req.flash('signupMessage', JSON.stringify(err)));
				
				}
				
                       }else{ 
                    return done(null, newUser);
						}
                });
              

        });

    }));

	 passport.use('local-login', new LocalStrategy({
        // by default, local strategy uses username and password, we will override with email
        usernameField : 'email',
        passwordField : 'password',
        passReqToCallback : true // allows us to pass back the entire request to the callback
    },
    function(req, email, password, done) { // callback with email and password from our form

        // find a user whose email is the same as the forms email
        // we are checking to see if the user trying to login already exists
        User.findOne({ 'email' :  email }, function(err, user) {
            // if there are any errors, return the error before anything else
            if (err)
                return done(err);

            // if no user is found, return the message
            if (!user)
                return done(null, false, req.flash('loginMessage', 'No user found.')); // req.flash is the way to set flashdata using connect-flash

            // if the user is found but the password is wrong
            if (!user.authenticate(password))
                return done(null, false, req.flash('loginMessage', 'Oops! Wrong password.')); // create the loginMessage and save it to session as flashdata

            // all is well, return successful user
            return done(null, user);
        });

    }));


//facebook
    passport.use(new FacebookStrategy({
        clientID: configAuth.facebookAuth.clientID,
        clientSecret: configAuth.facebookAuth.clientSecret,
        callbackURL: configAuth.facebookAuth.callbackURL
      },
      function(accessToken, refreshToken, profile, done) {
            process.nextTick(function(){
                User.findOne({'facebook.id': profile.id}, function(err, user){
                    if(err)
                        return done(err);
                    if(user)
                        return done(null, user);
                    else {
                        var newUser = new User();
                        newUser.email = profile.emails[0].value;
                        newUser.password = new Buffer(crypto.randomBytes(16).toString('base64'), 'base64');
                        newUser.socialLogin.facebook.id = profile.id;
                        newUser.socialLogin.facebook.token = accessToken;
                        newUser.socialLogin.facebook.name = profile.name.givenName + ' ' + profile.name.familyName;
                        newUser.socialLogin.facebook.email = profile.emails[0].value;

                        newUser.save(function(err){
                            if(err) console.log(err)
                                
                            return done(null, newUser);
                        })
                        console.log(profile);
                    }
                });
            });
        }

    ));


     passport.use(new GoogleStrategy({

        clientID        : configAuth.googleAuth.clientID,
        clientSecret    : configAuth.googleAuth.clientSecret,
        callbackURL     : configAuth.googleAuth.callbackURL,

    },
    function(token, refreshToken, profile, done) {

        // make the code asynchronous
        // User.findOne won't fire until we have all our data back from Google
        process.nextTick(function() {

            // try to find the user based on their google id
            User.findOne({ 'google.id' : profile.id }, function(err, user) {
                if (err)
                    return done(err);

                if (user) {

                    // if a user is found, log them in
                    return done(null, user);
                } else {
                    // if the user isnt in our database, create a new user
                    var newUser = new User();
                        newUser.email = profile.emails[0].value;
                        newUser.password = new Buffer(crypto.randomBytes(16).toString('base64'), 'base64');
                    newUser.socialLogin.google.id    = profile.id;
                    newUser.socialLogin.google.token = token;
                    newUser.socialLogin.google.name  = profile.displayName;
                    newUser.socialLogin.google.email = profile.emails[0].value; // pull the first email

                    // save the user
                    newUser.save(function(err) {
                        if (err)
                            throw err;
                        return done(null, newUser);
                    });
                }
            });
        });

    }));



};

Answer 1

这个:

require('./config/passport')(passport);

大致相当于:

var pp = require('./config/passport');
pp(passport);

解释一下，require('./config/passport') 返回一个需要一个参数的函数。您可以直接在上面的第一种形式中调用该函数，也可以将其分配给一个变量然后调用它。