Express framework knowledge - Art template template, cookie, session

Express frame

Set up a server

const express = require('express')

const app = express();


app.get('/',(request,respone)=>{
    
  respone.end('hello express!!')
})



app.listen(3000,() => {
    
  console.log('Express web server is listen at 3000 port!');
})

obtain post、get Request parameters

obtain get Parameters , It's through request.query

obtain post Parameters , Use

const app = express()
app.use(express.urlencoded({ extended: false }))
app.use(express.json())

const express = require('express')
const path = require('path')
const fs = require('fs');
const app = express();

app.use(express.urlencoded({
     extended: false }))
app.use(express.json())

app.get('/register',(request,respone)=>{
    
  let filepath = path.join(__dirname,'register.html')

  let content = fs.readFileSync(filepath,'utf-8')

  respone.send(content)

  // console.log(request.query);
})


app.get('/',(request,respone)=>{
    
  respone.end('hello express!!')
})

app.post('/register',(request,respone) => {
    
  let {
    username,email,password,repassword} = request.body


})


app.listen(3000,() => {
    
  console.log('Express web server is listen at 3000 port!');
})

Get static resources

Create a folder at the root of the project public As the root , stay pubilc Created in image Folder , Put static resources in the folder

Write... In the backend file app.use(express.static(path.join(__dirname,'public')))

Turn on the server , Input http://localhost:3000/image/1.png

You can get the path of static resources , On the front end html Of img Tag write <img src="/image/1.png" alt="">

It can be displayed on the page

art-template Templates

It can replace the above method of opening files .

//  These four lines of code ,  The initialization of the template engine 
//  introduce express-art-template,  Use the corresponding engine 
app.engine('html', require('express-art-template'));
//  Project environment settings ：
//  Production environment ( on-line ) production
//  development environment  development
app.set('view options', {
    
    debug: process.env.NODE_ENV !== 'production'
});
//  Set the directory in which to find template files 
app.set('views', path.join(__dirname, 'views'));
//  Set the suffix of the template to html
app.set('view engine', 'html');


app.get('/register',(request,respone)=>{
    
  respone.render('register')// Core code 
})

art-template Template transfer data

// Server code 
app.get('/register',(request,respone)=>{
    
  let data = {
    num:1,num2:3,books:["《 Journey to the west 》","《 A dream of red mansions 》","《 Water margin 》","《 The romance of The Three Kingdoms 》"]};
  respone.render('register',data)
})

 <div>
      <p>{
   {num}}</p>
      <p>{
   {num2}}</p>
 </div>
  <ul>
    {
   {each books}}
      <li>{
   {$value}}</li>
    {
   {/each}}
  </ul>
 {
   {if num > num2}}
  <p>p Labels do not necessarily show </p>
{
   {/if}}

Page effects ：

Hook function before processing the request
In the server-side code ：

function checklogin(req,res,next){
    
  console.log(" Execute this before executing the code ");
  next();
}

app.use(checklogin)

Get parameters of dynamic route

    <h1>List page </h1>
    <hr>
    <ul>
      <li><a href="/detali/1"> Journalism 1</a></li>
      <li><a href="/detali/2"> Journalism 2</a></li>
      <li><a href="/detali/3"> Journalism 3</a></li>
      <li><a href="/detali/4"> Journalism 4</a></li>
    </ul>

Server code ：

app.get('/register',(request,respone)=>{
    
    respone.render('register')
})


app.get('/detali/:id',(request,respone)=>{
    
  console.log(request.params);
})

//{ id: '1' }

The syntax format inherited by the template
The child template inherits the parent template

<!-- The parent template -->
<h1>List page </h1>
<hr>
{
   {block 'content'}}
<ul>
  <li><a href="/detali"> Journalism 1</a></li>
  <li><a href="/detali"> Journalism 2</a></li>
  <li><a href="/detali"> Journalism 3</a></li>
  <li><a href="/detali"> Journalism 4</a></li>
</ul>
{
   {/block}}

<!-- Sub template -->
{
   {extend './register.html'}}

{
   {block 'content'}}
<p>detali page </p>

{
   {/block}}

Template filter

const express = require('express')
const template = require('art-template')
const app = express();

template.defaults.imports.haha = function(value){
    
  return value * 200
}

app.get('/register',(request,respone)=>{
    
  let data = {
    
    num:1
  }
  respone.render('register',data)
})

<h1>Register</h1>

{
   {num | haha}}

cookie

Set up and get cookie
You need to install cookie-parser modular

const express = require('express')
const cookieParser = require('cookie-parser')
const app = express();

app.use(cookieParser())


app.get('/set_cookie',(request,response)=>{
    
  response.cookie('name','node',{
    maxAge:60000}) // Set up cookie The storage time of 
  response.cookie('age',11)// If it is not set, the session will be closed by default , Just destroy it 
  response.send(' Set up cookie Information ');
})

app.get('/get_cookie',(request,response)=>{
    

  let name = request.cookies['name'];
  let age = request.cookies['age'];

  console.log(name);
  console.log(age);

  response.send(` Set up cookie The message is ：${
      name},${
      age}`)
})


app.listen(3000,() => {
    
  console.log('Express web server is listen at 3000 port!');
})

session

characteristic ：
1、session Data is saved on the server side
2、session Is stored in the form of keys and values
3、session Depend on cookie, Every session The identification of the client corresponding to the information is saved in cookie in

Use ：

First install and introduce ：cookie-session

const cookieSession = require('cookie-session');

Sign up to app in ：

app.use(cookieSession({
    
    name:"my_session",  //name by session name , Just start a string by yourself 
    keys:["$^%%&^&%$RT%&TYGSGSFRR554785432$#@$$#%[email protected]#%"],  
    //  Internal encryption requires keys, keys For random strings 
    maxAge: 1000 * 60 * 60 * 24   //  Expiration time 
}))

Set up session：req.session[“name”] = "session_node"

obtain session：let name = req.session[“name”]

The complete code is as follows ：

// 1、 Install first ：yarn add cookie-session 
//  If you make a mistake , Add version number later , Then just keep returning  yarn add [email protected]
// 2、 Set to app in  
const cookieSession = require('cookie-session');
app.use(cookieSession({
    
    name:"my_session",  //name by session name , Just start a string by yourself 
    keys:["$^%%&^&%$RT%&TYGSGSFRR554785432$#@$$#%[email protected]#%"],  
    //  Internal encryption requires keys, keys For random strings 
    maxAge: 1000 * 60 * 60 * 24   //  Expiration time 
}))

app.get("/setSession",(req,res)=>{
    
    // Set up session
    req.session["name"] = "session_node"
    req.session["age"] = 11 
    
    res.send(" Set up Session")
})

app.get("/getSession",(req,res)=>{
    
    // obtain session Information 
    let name = req.session["name"]
    let age = req.session["age"]
    res.send(` obtain Session, ${
      name}, ${
      age}`);
})