NodeJS Bolg Combat Notes

An interface

1.1 Node processes HTTP requests

What is the process from entering an address in the browser to displaying it?
- DNS resolution, establishing TCP connections, and sending HTTP requests
- The server receives the HTTP request, processes it, and returns it
- The client receives the returned data, processes it, and renders the page

Processing HTTP requests

NPM init initializes the project

Const HTTP = the require (" HTTP "); Const server = http.createserver ((req, res) => {res.end(" Hello world ")}); server.listen(8000)Copy the code

Get request and QueryString

index.js

const http = require("http"); const querystring = require("querystring"); const server = http.createServer((req, res) => { console.log("method: ", req.method); //==> GET const url = req.url; console.log("url: ", url); req.query = querystring.parse(url.split("?" ) [1]); console.log("qurey: ", req.query); res.end(JSON.stringify(req.query)); }); server.listen(8000);Copy the code

node index.js
Browser visit http://localhost:8000/? a=100&b=200

Post requests and Postdata

Postman/Chrome plugin emulated POST requests

index.js

const http = require("http"); Const server = http.createserver ((req, res) => {if (req.method === "POST") {// Console. log("content-type:", req.headers["content-type"]); // let postData = ""; req.on("data", (chunk) => { postData += chunk.toString(); }); req.on("end", () => { console.log(postData); res.end("hello world"); }); }}); server.listen(8000);Copy the code

routing
- - github.com/
    - github.com/username
    - Github.com/username/XX…

Composite sample

const http = require("http"); const querystring = require("querystring"); const server = http.createServer((req, res) => { const { method, url } = req; const path = url.split("?" ) [0]; const query = querystring.parse(url.split("?" ) [1]); // Set the return format to JSON res.setheader (" content-type ", "application/ JSON "); // Return data const resData = {method, url, path, query,}; if (method === "GET") { res.end(JSON.stringify(resData)); } if (method === "POST") { let postData = ""; req.on("data", (chunk) => { postData += chunk.toString(); }); req.on("end", () => { resData.postData = postData; res.end(JSON.stringify(resData)); }); }}); server.listen(8000);Copy the code

1.2 Setting up the development environment

The Nodemon monitors file changes and automatically restarts the Node
Cross-env sets environment variables, compatible with MAC/Window/Linux

package.json

{"main": "bin/www.js", "scripts ": {" dev ":" cross-env NODE_ENV=dev nodemon. /bin/www.js ", "PRD ": Cross-env NODE_ENV=production nodemon./bin/www.js}}Copy the code

process.env.NODE_ENV

Bin /www.js only cares about the HTTP pure technology layer

const http = require('http') const serverHandle = require('.. /app') const PORT = 8000 const server = http.createServer(serverHandle) server.listen(PORT)Copy the code

app.js

Const serverHandle = (req, res) => {// Set the return format to JSON res.setheader (' content-type ', 'application/json') // Get path req.path = req.url.split('? Query = queryString.parse (req.url.split('? ') [1])})Copy the code

1.3 Development interface (database is not connected, login is not considered)

Initializing a Route

app.js

const handleBlogRouter = require('./src/router/blog') const handleUserRouter = require('./src/router/user') const ServerHandle = (req, res) => {// Set the return format to JSON res.setheader (' content-type ', 'application/ JSON ')}; // Get path const url = req.url; The req. Path = url. Split ('? Query = queryString.parse (req.url.split('? Const blogData = handleBlogRouter(req, res); ')[1]) // Handle blog routing const blogData = handleBlogRouter(req, res); if(blogData){ res.end(JSON.stringify(blogData)); return; } // handle user const userData = handleUserRouter(req, res); if(userData){ res.end(JSON.stringify(userData)); return; } // No route is matched, return 404 res.writeHead(404, {" content-type ":" text-plain "}); Res. Write (" 404 Not Found \ n "); res.end(); } module.exports = serverHandleCopy the code

src/router/blog.js

const handleBlogRouter = (req, Res) => {const method = req.method // GET POST const id = req.query.id // GET the list of blogs if(method === 'GET' && req.path === = '/api/blog/list') { return { msg: 'this is blog list api' } } // ... } module.exports = handleBlogRouterCopy the code

src/router/user.js

const handleUserRouter = (req, Res) => {const method = req.method // GET POST const id = req.query.id // log in if(method === 'POST' &&req.path === = '/ user/login ') {return {MSG: 'this is login API '}} //... } module.exports = handleUserRouterCopy the code

SRC /model/ resmodel.js // only care about the state

class BaseModel { constructor(data, message) { if(typeof data === 'string') { this.message = data data = null message = null } if(data) { this.data = data }  if(message) { this.message = message } } } class SuccessModel extends BaseModel { constructor(data, message) { super(data, message) this.errno = 0 } } class ErrorModel extends BaseModel { constructor(data, message) { super(data, message) this.errno = -1 } } module.exports = { SuccessModel, ErrorModel }Copy the code

src/router/blog.js

// Only care about routing

const { getList} = require('.. / controller/blog "); const { SuccessModel, ErrorModel } = require('.. / model/resModel "); const handleBlogRouter = (req, Res) => {const method = req.method // GET POST const id = req.query.id // GET the list of blogs if(method === 'GET' && req.path === = '/ API/blog/list') {const author = the req. Query. The author | | '; const keyword = req.query.keyword || '' ; const result = getList(author, keyword) return result.then(listData => { return new SuccessModel(listData) }) } // ... } module.exports = handleBlogRouterCopy the code

Return false data

SRC /controller/blog.js only cares about the data manipulation database

Const getList = (author, keyword)=>{return [{id:1, title: "title1", content: "test text", createTime: 1546620491112, author: 'z3'}, //...  } module.exports = { getList }Copy the code

app.js

Const getPostData = (req) => {const promise = new promise (resolve, reject) => {if(req.method! == 'POST') { resolve({}) return } if(req.headers['content-type'] ! == 'application/json') { resolve({}) return } let postData = '' req.on('data', chunk => { postData += chunk.toString() }) req.on('end', () => { if(! postData) { resolve({}) return } resolve( JSON.parse(postData) ) }) }) return promise }Copy the code

Const serverHandle = (req, res) => {// Set the return format to JSON res.setheader (' content-type ', 'application/json') // Get path req.path = req.url.split('? Query = queryString.parse (req.url.split('? ')[1]) // Post data getPostData(req).then(postData => {req. Body = postData // Login route const userResult = handleUserRouter(req, Res) if(userResult) {userresult. then(userData => {res.end(json.stringify (userData))}) return} // Process blog route const blogResult = handleBlogRouter(req, Res) if(blogResult) {blogresult. then(blogData => {res.end(json.stringify (blogData))}) return} // No route is hit res.writeHead(404, {'Content-type': 'text/plain'}) res.write('404 Not Found! \n') res.end() }) }Copy the code

MySQL data store

2.1 build library

Click the library icon in MySQLWorkbench to create the library

或 CREATE SCHEMA `myblog` ;

Table 2.2 built

In MySQLWorkbench, myblog > Tables > right-click > create table > users or blogs
datatype
- Varchar (50) length 50
- Longtext longtext with maximum size of 4G
- Int integer
- bigint(20)
PK main construction cannot be repeated
NN cannot be empty
Automatic AI increase
Click the apply button to finish

Table 2.3 operation

Using SQL statements

use myblog; show tables; Error Code: 1175. You are using safe update mode an... Execute SET SQL_SAFE_UPDATES=0Copy the code

increase

  insert into users(username, `password`, realname) values('zhang3'.'123'.'Joe');  
  insert into users(username, `password`, realname) values('li4'.'123'.'bill');  
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delete

-- delete delete from users where username='li4'; Update users set state='0' where username='li4'; Select * from users where state<> '0';Copy the code

change

Update users set realName =" li4 "where username='li4';Copy the code

check

  Check -
  select * from users;  
  select id, username from users;  
  Select * from 'where'
  select * from users where username="zhang3";  
  select * from users where username="zhang3" and `password`='123';  
  select * from users where username="zhang3" or `password`='123';  
  -- Query like fuzzy query
  select * from users where username like "%zhang%";  
  Select order by order
  select * from users order by id;  
  -- Order desc
  select * from users order by id desc;  
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2.4 Node Operating mySQL

npm i mysql

index.js

const mysql = require("mysql");  
  
// Create a link object
const con = mysql.createConnection({  
  host: "localhost".user: "root".password: "XXXXXX".port: "3306".database: "myblog"});// Start the connection
con.connect();  
  
// Execute the SQL statement
const sql = "select * fromt users";  
con.query(sql, (err, result) = > {  
  if (err) {  
    console.error(err);  
    return;  
  }  
  console.log(result);  
});  
  
// Close the connection
con.end();  
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Errno: 1064 use mysql; alter user 'root'@'localhost' identified with mysql_native_password by 'XXXXXX'; flush privileges;Copy the code

src/conf/db.js

const env = process.env.NODE_ENV let MYSQL_CONF if(env === 'dev') { MYSQL_CONF = { host: 'localhost', user: 'root', password: 'XXXXXX ', port: '3306', database: 'myblog'}} if(env === 'production') {MYSQL_CONF = {host: 'localhost', user: 'root', password: 'XXXXXX', port: '3306', database: 'myblog' } } module.exports = { MYSQL_CONF }Copy the code

src/db/mysql.js

const mysql = require('mysql') const { MYSQL_CONF } = require('./.. /conf/db') const con = mysql.createconnection (MYSQL_CONF) const con = mysql.createconnection (MYSQL_CONF) const con = mysql.createconnection (MYSQL_CONF exec(sql) { const promise = new Promise((resolve, reject) => { con.query(sql, (err, result) => { if(err) { reject(err) return } resolve(result) }) }) return promise } module.exports = { exec }Copy the code

2.5 connecting apis to mySQL

SRC /controller/blog.js only cares about the data manipulation database

const { exec } = require('./.. /db/mysql') const getList = (author, keyword) => { let sql = `select * from blogs where 1=1 ` if(author) { sql += `and anthor='${author}' ` } if(keyword) { sql += `and title like '%${keyword}%' ` } sql += `order by createtime desc; ` return exec(sql) } // ... module.exports = { getList }Copy the code

SRC /router/blog.js // only care about routing

const { getList} = require('.. / controller/blog "); const { SuccessModel, ErrorModel } = require('.. / model/resModel "); const handleBlogRouter = (req, Res) => {const method = req.method // GET POST const id = req.query.id // GET the list of blogs if(method === 'GET' && req.path === = '/ API/blog/list') {const author = the req. Query. The author | | '; const keyword = req.query.keyword || '' ; const result = getList(author, keyword) return result.then(listData => { return new SuccessModel(listData) }) } // ... } module.exports = handleBlogRouterCopy the code

app.js

const handleBlogRouter = require('./src/router/blog') const serverHandle = (req, res) => { // ... Const blogData = handleBlogRouter(req, res); if(blogData){ res.end(JSON.stringify(blogData)); return; // Handle user // failed route, return 404} module.exports = serverHandleCopy the code

Three login

3.1 the cookie and session

cookie
- - A cookie is a string stored in the browser (up to 5KB)
    - Not shared across domains
    - Formats such as k1 = v1; k2=v2; k3=k3; Therefore, structured data can be stored
    - Each time an HTTP request is sent, the cookie of the request domain is sent to the server
    - The server can modify the cookie and return it to the browser
    - Cookies can also be modified using JS in the browser (with limitations)
- JS operating cookie
  - ```
  // add document.cookie = 'k1=100; 'Copy the code
```
- The server operates cookies
  - ```
  // Parse cookie req.cookie = {}; const cookieStr = req.headers.cookie || ""; // console.log(cookieStr); cookieStr.split(";" ).map(item => { if (! item) return; const arr = item.split("="); const key = arr[0].trim(); const value = arr[1].trim(); req.cookie[key] = value; });Copy the code
```
- Use httpOnly to limit front-end changes to cookies, and expires to set an expiration time
```
  res.setHeader( "Set-Cookie", `userid=${userId}; path='/'; httpOnly; expires=${getCookieExpires()}` );Copy the code
```
- Cookie Login Process
  - 1. The front-end sends the username password in cookie to the back-end. 2. 3. Verify successfully. Write cookies to userID and set httpOnly and Expires to front-end 4. When the front end visits the back end, the browser will automatically take userID cookid 5. The backend verifies the userID to determine whether to log in

session

Problems with cookies
- Problem: Expose username, dangerous. Solution: The userID can be stored in the cookie, and the server corresponds to the username — this is session

Session code example

// session data const SESSION_DATA = {};Copy the code

Session let needSetCookie = false; let userId = req.cookie.userid; if (userId) { if (! SESSION_DATA[userId]) { SESSION_DATA[userId] = {}; } } else { needSetCookie = true; userId = `${Date.now()}_${Math.random()}`; SESSION_DATA[userId] = {}; } req.session = SESSION_DATA[userId];Copy the code

The router/user.js backend sets user data to req.session to ensure security

If (method === "POST" &&req. path === "/ API /user/login") {const {username, password} = req.body; const result = login(username, password); Return result.then(data => {if (data.username) {// Set session req.session.username = data.username; req.session.realname = data.realname; return new SuccessModel(data); } return new ErrorModel(" login failed "); }); }Copy the code

3.2 Session Writes redis

The problem of the session
- SESSION_DATA occupies nodeJS memory
  1. The memory is overloaded due to heavy traffic
  2. After the official launch, the system runs multiple processes, and the memory between processes cannot be shared
redis
- - Data is stored in memory
    - Compared to mysql, the access speed is faster
    - It costs more and has less data to store
Why is Sessin suitable for Redis
- - Session access is frequent and has high performance requirements
    - Session does not consider loss of data due to power outages
    - The amount of session data is not too large
Why is site data not redis
- - Operation frequency is not high
    - Power outages cannot be lost, they must be preserved
    - Too much data and too high memory cost

Redis basis

The installation

brew install redis  
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Start the server

redis-server  
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Start the cli redis – cli

set get

Set myname zhang3 get myname Query all keys delete key del mynameCopy the code

3.3 Develop the login function node link redis

demo

npm i redis --save

  const redis = require('redis')  
    
  const client = redis.createClient(6379.'127.0.0.1');  
    
  client.on('error'.err= >{  
      console.error(err)  
  })  
    
  client.set('myname'.'zhangsan2',redis.print)  
  client.get('myname'.(err,val) = >{  
      if(err){  
          console.log(err);  
          return;  
      }  
      console.log('val:',val);  
      client.quit()  
  })  
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Encapsulating tool function

config/db.js

// let REDIS_CONF if (env === 'dev') {REDIS_CONF = {port: 6379, host: '127.0.0.1'}} if (env === 'production') {redis REDIS_CONF = {port: 6379, host: '127.0.0.1'}} module.exports = {REDIS_CONF}Copy the code

db/redis.js

const redis = require("redis");  
const { REDIS_CONF } = require(".. /config/db");  
  
// Create client without quit() because it is singleton mode
const client = redis.createClient(REDIS_CONF.port, REDIS_CONF.host);  
client.on("error".err= > {  
  console.error(err);  
});  
  
const set = (key, val) = > {  
  if (typeof val === "object") {  
    // We need val to be a string
    val = JSON.stringify(val);  
  }  
  client.set(key, val, redis.print);  
};  
  
const get = key= > {  
  const promise = new Promise((resolve, reject) = > {  
    client.get(key, (err, val) = > {  
      if (err) {  
        reject(err);  
        return;  
      }  
      // Return null if no data is retrieved
      if (val === void 0) {  
        resolve(null);  
        return;  
      }  
      // Try catch is for compatibility with json.parse
      try {  
        resolve(JSON.parse(val));  
      } catch(error) { resolve(val); }}); });return promise;  
};  
  
module.exports = {  
  set,  
  get  
};  
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router/blog.js

const loginCheck = req= > {  
  console.log("req.session",req.session);  
  if(! req.session.username) {return Promise.resolve(  
      new ErrorModel('Not logged in'))}}// Create a new blog interface
  if (method === "POST" && req.path === "/api/blog/new") {  
  
    const loginCheckResult = loginCheck(req)  
    if (loginCheckResult) {  
      / / not logged in
      return loginCheckResult  
    }  
    / / have to log in
    req.body.author = req.session.username / / false data
    const result = newBlog(req.body)  
    return result.then(data= > {  
      return new SuccessModel(data)  
    })  
  }  
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app.js

const { get, set } = require("./src/db/redis");  
  
// Parse session (using redis)
  let needSetCookie = false;  
  let userId = req.cookie.userid;  
  console.log("userId", userId);  
  if(! userId) { needSetCookie =true;  
    userId = `The ${Date.now()}_The ${Math.random()}`;  
    // Initializes session initialization in Redis
    set(userId, {});  
  }  
  // Create a sessionId attribute for req,
  req.sessionId = userId;  
  get(req.sessionId)  
    .then((sessionData) = > {  
      if(! sessionData) {// Initializes session initialization in Redis
        set(req.sessionId, {});  
        / / set the session
        req.session = {};  
      } else {  
        req.session = sessionData;  
      }  
      return getPostData(req);  
    })  
    .then((postData) = > {  
      req.body = postData;  
      const blogResult = handleBlogRouter(req, res);  
      if (blogResult) {  
        blogResult.then((blogData) = > {  
          if (needSetCookie) {  
            res.setHeader(  
              "Set-Cookie".`userid=${userId}; path='/'; httpOnly; expires=${getCookieExpires()}`  
            );  
          }  
          res.end(JSON.stringify(blogData));  
        });  
        return;  
      }  
      const userResult = handleUserRouter(req, res);  
  
      if (userResult) {  
        userResult.then((userData) = > {  
          if (needSetCookie) {  
            res.setHeader(  
              "Set-Cookie".`userid=${userId}; path='/'; httpOnly; expires=${getCookieExpires()}`  
            );  
          }  
          res.end(JSON.stringify(userData));  
        });  
        return;  
      }  
      // Failed route: 404 is returned
      res.writeHead(404, {  
        "Content-type": "text/plain"}); res.write("404 Not Found\n");  
      res.end();  
    });  
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Four log

4.1 Log Types

Access log
Custom logging (including custom events, error logging, and so on)

4.2 Node File Operation stream

const fs = require("fs"); const path = require("path"); const fileName = path.resolve(__dirname, "data.jon.txt"); // read file fs.readFile(fileName, (err, data) => { if (err) { console.error(err); return; } // Data is binary and needs to be converted to the string console.log(data.tostring ()); }); // write file const content = "new content\n"; Const opt = {flag: "a", // append, w}; fs.writeFile(fileName, content, opt, (err) => { if (err) { console.error(err); return; }}); // exists fs.exists(fileName, (exist) => { console.log(exist); });Copy the code

pipe

const path = require("path")  
const fs = require("fs")  
  
const fileName1 = path.resolve(__dirname,'data.txt')  
const fileName2 = path.resolve(__dirname,'data-back.txt')  
  
const readSteam = fs.createReadStream(fileName1)  
const writeSteam = fs.createWriteStream(fileName2)  
  
readSteam.pipe(writeSteam)  
readSteam.on('data',chunk=>{  
    console.log(chunk.toString());  
})  
readSteam.on('end',()=>{  
    console.log("copy done");  
})  
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  const http = require('http');  
  const path = require("path")  
  const fs = require("fs")  
  const fileName1 = path.resolve(__dirname,'data.txt')  
  const server = http.createServer((req, res) = >{  
      if(the req. Method = = = "GET") {const readSteam = fs.createReadStream(fileName1)  
          readSteam.pipe(res)  
      }  
  })  
  server.listen(8000)  
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4.3 Developing and Using the Log Function

src/logs/access.log

src/logs/error.log

src/logs/event.log

src/utils/log.js

const path = require('path')  
const fs = require("fs")  
  
/ / write logs
function writeLog(writeStream, log) {  
    writeStream.write(log + '\n')}/ / generated writeStream
function createWriteStream(fileName) {  
    const fullFileName = path.join(__dirname, ".. /.. /logs/", fileName)  
    const writeStream = fs.createWriteStream(fullFileName, {  
        flags: 'a'  
    })  
    return writeStream;  
}  
  
// Write access logs
const accessWriteStream = createWriteStream('access.log')  
  
function access(log) {  
    writeLog(accessWriteStream, log)  
}  
  
module.exports = {  
    access  
}  
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src/app.js

const serverHandle = (req, res) = > {  
  // Log access
  access(  
    `${req.method} -- ${req.url} -- ${  
      req.headers["user-agent"]} -- The ${Date.now()}`  
  );  
/ /...
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4.4 Splitting log files and analyzing log content

- Log content accumulates slowly and cannot be handled in a single file
  - Log files by time: 2020-10-10.access.log
  - Implementation method: Run the crontab command on Linux
crontab
- To set a scheduled task, go to *****command
- Copy and rename access.log to 2020-10-10.access.log
- Clear the access.log file and continue to accumulate logs
- ```
! Log cp access.log $(data +%Y-%m-%d).access.log echo "" > access.logCopy the code
```

Log analysis

For example, analyze the ratio of Chrome to access.log logs
Logs are stored in rows, and a row is a log
Readline using NodeJS (Stream-based, efficient)

src/utils/readline.js

const fs = require("fs");  
const path = require("path");  
const readline = require("readline");  
  
/ / file name
const fileName = path.join(__dirname, ".. /.. /logs"."access.log");  
// Create read Stream
const readStream = fs.createReadStream(fileName);  
  
// Create a radline object
const rl = readline.createInterface({  
  input: readStream,  
});  
  
let chromeNum = 0;  
let sum = 0;  
  
// Read line by line
rl.on("line".(lineData) = > {  
  if(! lineData) {return;  
  }  
  // Record the total number of rows
  sum++;  
  
  const arr = lineData.split("--");  
  if (arr[2] && arr[2].indexOf("Chrome") > 0) {  
    // Add chrome numberchromeNum++; }}); rl.on("close".() = > {  
  console.log("Chrome ratio:" + chromeNum / sum);  
});  
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Five safety

* Server side attacks are very many, prevention means are also very many

This article covers only the common ones that can be prevented at the Web Server (NodeJS) level
Some attacks require hardware and services to support (OP support is required), such as DDOS

5.1 SQL injection

The most primitive and simple attack

Attack method: Enter a SQL fragment, eventually spliced into a piece of attack code
Precaution: Use mysql’s escape function to process input

  const mysql = require('mysql')  
  const login = (username, password) = > {  
    username = mysql.escape(username);  
    password = mysql.escape(password);  
    // ...  
  };  
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5.2 XSS attacks

Attack: In the page display content doping JS code, to obtain webpage information

Precaution: Convert generated JS special characters

& => &amp; < => &lt; > => &gt; "= > & quot; '= > & # x27; / => &#x2f;Copy the code

blog.js

const xss = require('xss');  
const newBlog = (blogData = {}) => {  
  const title = xss(blogData.title)  
  //...  
}  

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5.3 Password Encryption

Attack mode: Obtain the user name and password, and then try to log in to other systems

Precaution: Encrypt your password

const crypto = require("crypto"); // const SECRET_KEY = "AbEdQe_123#$"; Function md5(content) {let md5 = crypto.createHash("md5"); return md5.update(content).digest("hex"); } // function genPassword(password) {const STR = 'password=${password}&key=${SECRET_KEY}'; return md5(str); }Copy the code

Use Express for refactoring

6.1 Middleware Principles

NPM I express-generator-g create directory Express blog- Express

package.json
```
Scripts :{dev: cross-env NODE_ENV=dev nodemon./bin/ WWW}Copy the code
```

  app.use((req, res, next) = > {  
    console.log("Request to commence...", req.method, req.url);  
    next();  
  });  
    
  app.use('/api'.(req, res, next) = >{  
    console.log('Process/API routing')  
    next()  
  })  
    
  app.get("/api/get-cookit".(req, res, next) = > {  
    console.log("Get/API/get-Cookit routing");  
    res.json({ erron: 0.data: "ok" });  
  });  
    
  app.post("/api/get-post-data".(req, res, next) = > {  
    console.log("Post/API /get-post-data routing");  
    res.json({ erron: 0.data: "ok" });  
  });  
    
  app.use((req, res, next) = > {  
    / / 404
    res.json({ erron: 1.data: 404 });  
  });  
    
    
    
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Concatenate by next()

Many-sum functions can be passed

app.get("/api/get-cookit", loginCheck, (req, res, next) = > {  
  console.log("Get/API/get-Cookit routing");  
  res.json({ erron: 0.data: "ok" });  
});  
  
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6.2 Using middleware Mechanisms

app.js

Cookie var cookieParser = require('cookie-parser'); // Parse JSON POST data and mount it to req.body app.use(express.json()); // Parse non-JSON formats, mount to req.body app.use(express.urlencoded({extended: false}));Copy the code

App. Js log

/ / record log
var logger = require('morgan');  
  
const ENV = process.env.NODE_ENV;  
if(ENV ! = ="production") {  
  // Development environment/test environment
  app.use(logger("dev"));  
} else {  
  // Online environment
  const logFileName = path.join(__dirname, "logs"."access.log");  
  const writeStream = fs.createWriteStream(logFileName, {  
    flags: "a"}); app.use( logger("combined", {  
      stream: writeStream,  
    })  
  );  
}  
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The development environment outputs to the console online environment outputs to access.log

app.js session

// session redis  
const session = require('express-session')  
const RedisStore = require('connect-redis')(session)  
  
const redisClient = require("./db/redis");  
const sessionStore = new RedisStore({  
  client: redisClient,  
});  
app.use(  
  session({  
    secret: "WJiol#23123_".cookie: {  
      // path: '/', // Default configuration
      // httpOnly: true, // default configuration
      maxAge: 24 * 60 * 60 * 1000,},store: sessionStore,  
  })  
);  
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db/redis.js

const redis = require('redis')  
const { REDIS_CONF } = require('.. /conf/db.js')  
  
// Create a client
const redisClient = redis.createClient(REDIS_CONF.port, REDIS_CONF.host)  
redisClient.on('error'.err= > {  
    console.error(err)  
})  
  
module.exports = redisClient  
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app.js router

const userRouter = require('/ routes/user "); app.use('/api/user', userRouter);  
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routes/index.js

var express = require('express');  
var router = express.Router();  
  
// Add '/ API /blog/list' to app.useThe router. The get (/ list,function(req, res, next) {  
  res.json({ errno: 0.data:’OK’ });  
});  
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routes/user.js

var express = require('express');  
var router = express.Router();  
const { login } = require('.. /controller/user')  
const { SuccessModel, ErrorModel } = require('.. /model/resModel')  
  
router.post('/login'.function(req, res, next) {  
    const { username, password } = req.body  
    const result = login(username, password)  
    return result.then(data= > {  
        if (data.username) {  
            / / set the session
            req.session.username = data.username  
            req.session.realname = data.realname  
  
            res.json(  
                new SuccessModel()  
            )  
            return  
        }  
        res.json(  
            new ErrorModel('Login failed'))})});module.exports = router;  
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router/blog.js

const loginCheck = require('.. /middleware/loginCheck')  
router.post('/new', loginCheck, (req, res, next) = > {  
    req.body.author = req.session.username  
    const result = newBlog(req.body)  
    return result.then(data= > {  
        res.json(  
            new SuccessModel(data)  
        )  
    })  
})  
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loginCheck.js

const { ErrorModel } = require('.. /model/resModel')  
  
module.exports = (req, res, next) = > {  
    if (req.session.username) {  
        next()  
        return  
    }  
    res.json(  
        new ErrorModel('Not logged in'))}Copy the code

app.js 404

// Optimize 404 page prompt text
var createError = require('http-errors');  
app.use(function(req, res, next) {  
  next(createError(404));  
});  
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6.3 Middleware Implementation Roadmap

Analysis of the
- Register via app.use
- When encountering an HTTP request, determine which to trigger based on path and method
- Implement the next mechanism where the previous one triggers the next one through next

Use Koa2 for reconstruction

7.1 development koa2

The installation

npm i koa-generator -g  
Koa2 koa2-test  
npm i & npm run dev  
Copy the code

App. Js to log in

const session = require('koa-generic-session')  
const redisStore = require('koa-redis')  
const user = require('./routes/user')  
  
/ / the session configuration
app.keys = ['WJiol#23123_']  
app.use(session({  
  / / configuration cookies
  cookie: {  
    path: '/'.httpOnly: true.maxAge: 24 * 60 * 60 * 1000  
  },  
  / / configure redis
  store: redisStore({  
    // all: '127.0.0.1:6379' // write local redis to death
    all: `${REDIS_CONF.host}:${REDIS_CONF.port}`  
  })  
}))  
  
app.use(user.routes(), user.allowedMethods())  
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routes/user.js

const router = require('koa-router') ()const { login } = require('.. /controller/user')  
const { SuccessModel, ErrorModel } = require('.. /model/resModel')  
// Route prefix
router.prefix('/api/user')  
  
router.post('/login'.async function (ctx, next) {  
    const { username, password } = ctx.request.body  
    const data = await login(username, password)  
    if (data.username) {  
        / / set the session
        ctx.session.username = data.username  
        ctx.session.realname = data.realname  
        // return the front-end data
        ctx.body = new SuccessModel()  
        return  
    }  
    ctx.body = new ErrorModel('Login failed')})module.exports = router  
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app.js logger

const logger = require('koa-logger')  
const path = require('path')  
const fs = require('fs')  
const morgan = require('koa-morgan')  
  
// logger  
app.use(async (ctx, next) => {  
  const start = new Date(a)await next()  
  const ms = new Date() - start  
  console.log(`${ctx.method} ${ctx.url} - ${ms}ms`)})const ENV = process.env.NODE_ENV  
if(ENV ! = ='production') {  
  // Development environment/test environment
  app.use(morgan('dev'));  
} else {  
  // Online environment
  const logFileName = path.join(__dirname, 'logs'.'access.log')  
  const writeStream = fs.createWriteStream(logFileName, {  
    flags: 'a'  
  })  
  app.use(morgan('combined', {  
    stream: writeStream  
  }));  
}  
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7.2 Analysis of KOA2 Middleware

8 Online Configuration

8.1 Online environment challenges

Server stability
Take full advantage of server hardware resources to improve performance
Online logging

8.2 PM2 can solve the above problems

Daemon process, system crash automatic restart
Start multiple processes to make full use of CPU and memory
Provides the log recording function

8.3 PM2

Download and install

  npm i pm2 -g  
  pm2 --version  
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The basic use

package.json

"scripts": {  
    "prd": "cross-env NODE_ENV=production pm2 start bin/www",},Copy the code

Common commands
- pm2 start app.js
- pm2 list
- pm2 restart <AppName>/<id>
- pm2 stop <AppName>/<id>
- pm2 delete <AppName>/<id>
- pm2 info <AppName>/<id>
- pm2 log <AppName>/<id>
- pm2 moint <AppName>/<id>
The process to protect
- Simulation error
```
if(the req. Url = = = '/ err) {throw new Error()}Copy the code
```
- Pm2 list Indicates that the restart is restarted
  
  Pm2 log app Uses the PM2 log to view logs and analyze causes

Commonly used configuration

pm2.conf.json

{  
    "apps": {  
        "name": "pm2-test-server"."script": "app.js"."watch": true."ignore_watch": [  
            "node_modules"."logs"]."instances": 4./ / process
        "error_file": "logs/err.log"."out_file": "logs/out.log"."log_date_format": "YYYY-MM-DD HH:mm:ss"}}Copy the code

An interface

1.1 Node processes HTTP requests

1.2 Setting up the development environment

1.3 Development interface (database is not connected, login is not considered)

MySQL data store

2.1 build library

Table 2.2 built

Table 2.3 operation

2.4 Node Operating mySQL

2.5 connecting apis to mySQL

Three login

3.1 the cookie and session

3.2 Session Writes redis

3.3 Develop the login function node link redis

Four log

4.1 Log Types

4.2 Node File Operation stream

4.3 Developing and Using the Log Function

4.4 Splitting log files and analyzing log content

Five safety

* Server side attacks are very many, prevention means are also very many

5.1 SQL injection

5.2 XSS attacks

5.3 Password Encryption

Use Express for refactoring

6.1 Middleware Principles

6.2 Using middleware Mechanisms

6.3 Middleware Implementation Roadmap

Use Koa2 for reconstruction

7.1 development koa2

7.2 Analysis of KOA2 Middleware

8 Online Configuration

8.1 Online environment challenges

8.2 PM2 can solve the above problems

8.3 PM2

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