nodejs渐入佳境[15]-express框架

最简单的服务器

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const express = require('express');

var app = express();


//返回html格式
app.get('/',(req,res)=>{
res.send('<h1>Hello world</h1>');
});

//返回json格式
app.get('/fast',(req,res)=>{
res.send({
name:'json',
likes:[
'reading',
'coding'
]
});
});
//监听端口
app.listen(3000);

访问:
localhost:3000
localhost:3000/fast

访问静态文件

创建public/help.html

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<!DOCTYPE html>
<html lang="en" dir="ltr">
<head>
<meta charset="utf-8">
<title></title>
</head>
<body>
<h1>Hello Jonson</h1>
</body>
</html>

express.js:

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const express = require('express');

var app = express();

// 参数是一个middleware
app.use(express.static(__dirname +'/public'));
//返回html格式
app.get('/',(req,res)=>{
res.send('<h1>Hello world</h1>');
});

//返回json格式
app.get('/fast',(req,res)=>{
res.send({
name:'json',
likes:[
'reading',
'coding'
]
});
});
//监听端口, 第二个回调是开启服务器后调用
app.listen(3000,()=>{
console.log('hello jonson');
});

访问:
http://localhost:3000/help.html
会打开public/help.html的页面并显示出来。

动态注入 express template engines

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npm install --save hbs

新建views/about.hbs:

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<!DOCTYPE html>
<html lang="en" dir="ltr">
<head>
<meta charset="utf-8">
<title></title>
</head>
<body>
<h1>{{currentYear}}</h1>
<footer>{{pageTitle}}</footer>
</body>
</html>

express.js:

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const express = require('express');
const hbs = require('hbs');
var app = express();

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




// 参数是一个middleware
app.use(express.static(__dirname +'/public'));
//返回html格式
app.get('/',(req,res)=>{
res.send('<h1>Hello world</h1>');
});

//返回json格式
app.get('/fast',(req,res)=>{
res.send({
name:'json',
likes:[
'reading',
'coding'
]
});
});

//动态传递参数。
app.get('/about',(req,res)=>{
res.render('about.hbs',{
pageTitle:'About Page',
currentYear:new Date().getFullYear()
});
});
//监听端口, 第二个回调是开启服务器后调用
app.listen(3000,()=>{
console.log('hello jonson');
});

访问:
localhost/about

模版封装

新建:views/partial/footer.hbs:

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<Header>
<footer>{{pageTitle}}</footer>
<Header>

view/abut.hbs:

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<!DOCTYPE html>
<html lang="en" dir="ltr">
<head>
<meta charset="utf-8">
<title></title>
</head>
<body>
<h1>{{currentYear}}</h1>
{{> footer}}
</body>
</html>

express.js:

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const express = require('express');
const hbs = require('hbs');
var app = express();

hbs.registerPartials(__dirname + '/views/partials');
app.set('view engine','hbs');
// 参数是一个middleware
app.use(express.static(__dirname +'/public'));


//返回json格式
app.get('/about',(req,res)=>{
res.render('about.hbs',{
pageTitle:'About Page',
currentYear:new Date().getFullYear()
});
});
//监听端口, 第二个回调是开启服务器后调用
app.listen(3000,()=>{
console.log('hello jonson');
});

访问:
localhost/about

express middleware

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const express = require('express');
const hbs = require('hbs');
const fs = require('fs');
var app = express();


hbs.registerPartials(__dirname + '/views/partials');
app.set('view engine','hbs');
// 参数是一个middleware
app.use(express.static(__dirname +'/public'));
//返回html格式
app.get('/',(req,res)=>{
res.send('<h1>Hello world</h1>');
});

//自定义middleware
app.use((req,res,next)=>{
var now = new Date().toString();
var log = `${now}:${req.method} ${req.url}`;
console.log(log);
fs.appendFile('server.log',log+'\n',(err)=>{});
next();

});
//返回json格式
app.get('/fast',(req,res)=>{
res.send({
name:'json',
likes:[
'reading',
'coding'
]
});
});

//返回文件,about.hbs在views文件夹下
app.get('/about',(req,res)=>{
res.render('about.hbs',{
pageTitle:'About Page',
currentYear:new Date().getFullYear()
});
});
//监听端口, 第二个回调是开启服务器后调用
app.listen(3000,()=>{
console.log('hello jonson');
});