learning  express  middleware

var express = require('express');var app = express();var log = 0var myLogger = function (req, res, next) {    log++;    console.log('var log =', log);    next();};app.use(myLogger);app.get('/', function(req, res){    res.send("hello world");});app.listen(3000);

result:

C:\Users\admin\WebstormProjects\learning-express-step5>node learning-express-step5.jsvar log = 1var log = 2var log = 3var log = 4

 

request time log:

var express = require('express');var app = express();var log = 0var myLogger = function (req, res, next) {    log++;    console.log('var log =', log);    next();};var requestTime = function(req, res, next){    req.requestTime = Date.now();    next();}app.use(myLogger);app.use(requestTime);app.get('/', function(req, res){    //res.send("hello world");    var responseText = 'hello world!
';    responseText +='Requested at: ' + req.requestTime + ''    res.send(responseText);});

result:

write middleware

var express = require('express');var app = express();var mw = require('./my-middleware');var log = 0;var myLogger = function (req, res, next) {    log++;    console.log('var log =', log);    next();};var requestTime = function(req, res, next){    req.requestTime = Date.now();    next();}app.use(myLogger);app.use(requestTime);app.use(mw({option1:'1',option2:'2'}));app.get('/', function(req, res){    //res.send("hello world");    var responseText = 'hello world!
';    responseText +='Requested at: ' + req.requestTime + ''    res.send(responseText);});app.listen(3000);

　　my-middleware.js  each request print log option1 and option2

module.exports = function (options) {    return function (req, res, next) {        console.log(options.option1);        console.log(options.option2);        next()    }

result:

C:\Users\admin\WebstormProjects\learning-express-step5>node learning-express-step5.jsvar log = 112var log = 212var log = 312