Nodejs road (three) - Nodejs framework of Express

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Express

Http native performance in some areas is not sufficient to cope with our development needs, so we need to use the framework to accelerate our development efficiency. The purpose of the framework is to improve efficiency, so that our code more uniform height

In Node, there are many Web development framework, we are here to learn expressthe main

Reference website: http://expressjs.com/

1. start

1.1 installation:

npm install --save express

1.2 hello world

var express = require('express')
var app = express()

app.get('/',function(req,res){
    //推荐使用express的方法
    res.send("hello world")
})

app.listen(3000,function(){
    console.log("express app is running ...")
})

1.3 Basic Routing

router

Request method
Request path
Request handler

get:

// When GET method request to / when performing a process corresponding to the function 
app.get ( '/', function (REQ, RES) { 
    res.send ( 'Hello World!' ) 
})

post:

// When the POST method request to / when performing a process corresponding to the function 
app.post ( '/', function (REQ, RES) { 
    res.send ( 'the Get Request POST A' ) 
})

1.4 static service

// /public资源
app.use(express.static('public'))
// /files资源
app.use(express.static('files'))
// /public/xxx
app.use('/public',express.static('public'))
// /static/xxx
app.use('/static',express.static('public'))

app.use('/static',express.static(path.join(__dirname,'public')))

2. Express configured to use in the `art-template`template engine

installation:

npm install --save art-template
npm install --save express-art-template

Configuration:

// Default Art 
app.engine ( 'Art', the require ( 'Template-Express-Art' ))
 // modified HTML 
app.engine ( 'HTML', the require ( 'Template-Express-Art'))

use:

// use the html modify the configuration of 
app.get ( '/', function (REQ, RES) {
     // Express default will go to projects in the views directory to find index.html 
    res.render ( 'index.html' , { 
        title: 'Hello World' 
    }) 
})

Note: If you want to change the default viewsview rendering storage directory, you can:

// The first parameter views do not mistake 
app.set ( 'views', the directory path)

3. Obtain Form GET request parameters in Express,

Express built-in API, you can directly through req.queryto get

req.query

Note: In the browser address input, the default is the get request

4. Gets the data in the POST request body Express,

No built-in API to obtain a form POST request body in Express, where we need to use a third-party package:body-parser

installation:

npm install --save body-parser

Configuration:

var Express = the require ( 'Express' )
 // of 0. The primer packet 
var bodyParser the require = ( 'body-Parser' ) 

var App = Express () 

// 1. Configure-Parser body 
// Just add this configuration, then req request will be more out of a property on an object: body 
// That can directly obtain the data through a form POST request body the req.body 
// the parse file application / X-WWW-form-urlencoded 
app.use (bodyParser.urlencoded ({ Extended: to false })) 

// the parse file application / JSON 
app.use (bodyParser.json ())

use:

app.use ( function (REQ, RES) { 
  res.setHeader ( 'the Content-the Type', 'text / Plain' ) 
  res.write ( 'you. Posted: \ n-' ) 
    
   // may be acquired by a form POST req.body data request body   
  res.end (the JSON.stringify (req.body, null , 2 )) 
})

Note: req.bodyReturns the object attribute values are strings

5. Use the tool to automatically restart the service nodemon

Here we can use a third-party tool named: nodemonto help us solve problems frequently modify the code to restart the server

nodemonIs based on a third-party command-line tool Node.js development, we need to use a stand-alone installation:

# Execute this command in any directory can have 
# That is all that is required - , Ltd. Free Join to install the package can be performed in any directory 
npm install --global nodemon

After installation, use:

# Before using the Node 
the Node app.js 

# now use nodemon 
nodemon app.js

As long as through the nodemon app.jsstart of the service, it will monitor your files change, when a file is changed, it will automatically help you restart the server

6.Express - crud (routing)

6.1 modularization

How module division:

Responsibility to a single module
View
angular
React
It is also very conducive to learning the three front-end framework

6.2 start

initialization
Template processing

6.3 Routing Design

6.4 Extraction routing module

router.js:

/ * 
 Router.js routing module 
    functions: 
        handles the routing 
        depending on the route setting request method + requests a specific request handler 
* / 
// modules to a single role, do not write without 
// object is to enhance partitioning module project code maintainable resistance, improve development efficiency 

var Express = the require ( 'Express' )
 // 1. Create a routing container 
var router = express.Router ()
 // 2. the router routes routes are mounted to the vessel 
router.get (' / Students. ', function (REQ, RES) { 

}) 
router.get ( ' / Students. / new new ', function (REQ, RES) { 
    res.render ( ' new.html ' ) 
}) 
router.post ( ' / Students. / new new ', function (REQ, RES) {
    
})
router.get('/students/edit',function(req,res){

})
router.post('/students/edit',function(req,res){

})
router.get('/students/delete',function(req,res){

})
//3.把 router 导出
module.exports = router

app.js:

var Router = the require ( "./ Router" ) 

// mount routing 
app.use (router)

6.5 API module design operating data

/ * 
Student.js 
data file module operating 
duties: operational data files, data processing only, do not care about the business 
* / 

/ * 
    get a list of all students 
    return array 
* / 
exports.find = function () { 

} 

/ * 
    Add save students 

* / 
exports.save = function () { 

} 

/ * 
    update student 
* / 
exports.update = function () { 

} 

/ * 
    delete student 
* / 
Exports. the delete = function () { 

}

6.6 Case - student management system - written in step

Process Template
Configuration Open static resources
Configuration template engine
Simple routing: / students render a still page out
Routing Design
Extraction routing module
As the next new business operations need to deal with file data, so we need to package student.js
First written student.js file structure
- Query API find a list of all students
- findById
- save
- updateById
- deleteById
Achieve specific functions
- Receipt of the request by routing
- Receiving a data request (get, post)
  - req.query
  - req.body
- Manipulating data using the data processing API
- The client sends a response to the result of the operation
Order of business functions
- List
- Add to
- edit
- delete
ES6 two important API: find, findIndex