How about HTTP in Node? Write your own 'CPG-server' static service

The preface

Writing a static service provides a deeper understanding of the HTTP modules in Node, which is what we originally intended. I’m sure you’ve all used http-Server, so we’re going to implement something similar here. Function as follows

After launching our module, type localhost:3000 to open the file in our public directory (index.html is open by default).
The debug plug-in is mainly used to output some logs on the command line. We only use basic functions, so there are no difficulties. It doesn’t poke here
The chalk plugin is likely to be used, which makes the command line output logs colorful and beautiful

The preparatory work

Our catalog is deconstructed as follows

Start our service and automatically open public/index.html
Bin /www.js is the configuration we will use to start the service from the command line later
Public is our static directory
App. Js master file
Config.js configuration file
Mppl.html is the template we compiled using EJS, which we will cover later

Start with the simplest config.js

let path = require('path');
let config = {
    hostname:'127.0.0.1', // Default host port:3000, // default port dir:path.join(__dirname,' '.'public') // Default open directory (absolute path)}; module.exports = config;Copy the code

The above code can understand, let’s start to write our main file

The core code app.js

1. Introduce the required dependency packages

let http = require('http');
let url = require('url');
let path = require('path');
let util = require('util');
let fs = require('fs');
let zlib = require('zlib');
let mime = require('mime'); // Get the content typelet debug = require('debug') (The '*'); // Printout controls output based on environment variableslet chalk = require('chalk'); / / a piece of chalklet ejs = require('ejs'); // Template engine //let config = require('./config');
let stat= util.promisify(fs.stat); //promise the fs.stat methodlet readdir = util.promisify(fs.readdir);
let template = fs.readFileSync(path.join(__dirname,'tmpl.html'),'utf8'); // Read the ejS template fileCopy the code

Mime parses the file to give you the content type, usage
Ejs rendering engine, we use the simplest function, will not be able to understand

2. Enable the HTTP service

/* Run conditions specify host name * specify port number to start * Specify directory to run */let config = require('./config'); // Import the configuration file class Server {// declaration classconstructor() { this.config = config; } handleRequest(req,res){make sure this is an instance}start(){// The method to start the servicelet server =http.createServer(this.handleRequest.bind(this));
        let{hostname,port} = this.config; Server.listen (port,hostname); debug(`http://${hostname}:${port}Start ') // Prints}} // to start a serviceletserver = new Server(); server.start(); // Call the start methodCopy the code

As of now, the simple service is enabled, so let’s test the effect

Perfect. The console prints out the content,

3. Implement the handleRequest method, which handles the request logic

List what we’re going to do

Parse the pathname of the URL
The path is spliced with the default path (G:// cpG-server /public)
Check whether it’s file or folder or 404

let stat= util.promisify(fs.stat); Stat async handleRequest(req,res){// Make sure this is an instancelet {pathname} = url.parse(req.url,true); // Get the path to the URLletp = path.join(this.config.dir,pathname); // public: G:/ cpp-server /public :// cpp-server /public/index. HTML //let statObj=await stat(p); }catch (e) {this.senderror (req,res,e)}}Copy the code

Try catch is used to catch errors. When the file does not exist, call sendError and implement the error handling method first

File does not exist logic, sendError()

sendError(req,res,e){ debug(util.inspect(e)); // The util module provides the method res.statuscode = 404; res.end('Not Found');
    }
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Now that I’ve written so much, let’s test the error file to see if I can print an error

Test perfect, at this point we should determine whether to open a file or directory, and give the corresponding method, let’s start the directory rendering method

Ejs render directory list

Declare a template template and mount it to the instance

let template = fs.readFileSync(path.join(__dirname,'tmpl.html'),'utf8'); // Read the ejS template file class Server{constructor(){this.template = template // mount to instance}}Copy the code

If it is a directory, render an HTML page to show the directory structure

if(statObj.isdirectory ()){// To list the contents of the directory, clicklet dirs= await readdir(p); //public directory structure =>[index.html,style.css]dirs =dirs.map(dir=>{
                    return {
                        filename:dir,
                        path:path.join(pathname,dir)
                    }
                });
                //dirsIs to render data / / format is as follows [{filename: index. HTML, path:'/index.html'},{{filename:style.css,path:' '/style.css}}]
                let str =ejs.render(this.template,{dirs}); // ejS render method // console.log(STR); res.setHeader('Content-Type'.'text/html; charset=utf-8');
                res.end(str);
            }
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Let’s take a look at the mppl. HTML template, and the EJS usage, and we’re only using the simplest one, so we should be able to understand it, right

<! DOCTYPE html> <html lang="en">
<head>
    <meta charset="UTF-8"> <title> title </title> </head> <body> // loopdirs<% dirs.map(item=>{%> <li><a href="<%=item.path%>"><%=item.filename%></a></li>
<%})%>
</body>
</html>

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Render directory structure, we’ve written it, let’s test it and see if it works

So far, no bugs, the next implementation if it is a file, directly render the content of the file

6. File rendering method, this.sendFile() method

sendFile(req,res,p,statObj){
     res.setHeader('Content-Type', mime.getType(p) + '; charset=utf-8'); fs.createReadStream(p).pipe(res); // pipe to writable stream}Copy the code

Function has been achieved pull, do not believe we test

The functionality is already there, but we asked for three more features
1. Check whether caching is supported
2. Check whether compression is supported
3. Check whether range requests are supported

6.1 Adding the Cache Function

Modify the sendFile() method to add three functions

 sendFile(req,res,p,statObj){// check whether there is a cacheif(this.cache(req,res,p,statObj)){// If there is a cache res.statusCode = 304; res.end();return} //2. Check whether compression is supported.... // check whether there is a range request.... }Copy the code

Cache () Cache method

There are two types of caching, mandatory caching and negotiated caching

Enforce caching of server catch-control and Expires
Negotiate last-Modified and Etag for the cache server
Negotiation Cache client if-modified-since if-none-match matches the server
Post baidu cache deconstruction for you to see

I think you get the idea after looking at this picture. Let’s start writing the cache method

cache(req,res,p,statObj){// Implement caching /* Force caching server cache-control Expires negotiation Caching server Last-Modified Etag negotiation caching clientif-modified-since  if-none-match etag ctime + file size last-Modified ctime Mandatory cache */ res.setheader ('Cache-Control'.'no-cache');
        res.setHeader('Expires', new Date(Date.now() + 10 * 1000).toGMTString()); // Resend the request after 10 secondslet etag = statObj.ctime.toGMTString() + statObj.size; // File modification time and file sizelet lastModified = statObj.ctime.toGMTString(); // File modification time res.setheader ('Etag', etag);
        res.setHeader('Last-Modified', lastModified);
        let ifNoneMatch = req.headers['if-none-match']; 
        let ifModifiedSince = req.headers['if-modified-since']; 
        if(etag ! =ifNoneMatch) {// Not equal, do not cachereturn false;
        }
        if(lastModified ! =ifModifiedSince) {// Same logicreturn false;
        }
        return true; // if not, go to cache}Copy the code

Now that the caching function is done, let’s test whether the header set is added

We’ve already implemented caching

6.2 Enabling compression

Zlib provides compression in Node

gzip(req,res,p,statObj){// Client accept-encoding: gzip, deflate, br // Server content-encoding: gziplet encoding = req.headers['accept-encoding']; // Get the received compression format of the request headerif (encoding) {
            if (encoding.match(/\bgzip\b/)) {
                res.setHeader('Content-Encoding'.'gzip')
                returnzlib.createGzip(); // Return a gzip stream}else if (encoding.match(/\bdeflate\b/)) {
                res.setHeader('content-encoding'.'deflate');
                returnzlib.createDeflate(); // Return createDeflate compressed stream}else {
                return false; // Compression is not supported otherwise}}else {
            return false; // Compression is not supported otherwise}}Copy the code

Modify the sendFile() method

sendFile(req,res,p,statObj){// check whether there is a cacheif(this.cache(req,res,p,statObj)){// If there is a cache res.statusCode = 304; res.end();return} //2, check whether compression res.setheader () is supported"Content-Type",mime.getType(p)+"; charset=utf8");
        let compress =this.gzip(req,res,p,statObj);
        if(compress){// Checks for compression. It returns a compressed streamreturn fs.createReadStream(p).pipe(compress).pipe(res);
        }else{// No compression is supportedreturnFs.createreadstream (p).pipe(res)} //3, check whether there is a range request.... }Copy the code

Use the 1.txt file to test

So far, so good, but there’s one last feature left, which implements scope requests

6.3 Implement the range request function

Range:bytes=0-3
Accept-range :bytes Content-range :bytes 0-3/ XXX Content-Length: XXX

Since there may be compression and scope requests at the same time, let’s change the previous code slightly

  sendFile(req,res,p,statObj){// 1. Check whether there is a cache.... //2, check whether compression is supported and add range request res.setheader ("Content-Type",mime.getType(p)+"; charset=utf8");
        let compress =this.gzip(req,res,p,statObj);
        let {start,end} = this.range(req,res,p,statObj); // Deconstruct the start and end positionsif(compress){// Checks for compression. It returns a compressed streamreturn fs.createReadStream(p,{start,end}).pipe(compress).pipe(res);
        }else{
            // res.setHeader("Content-Type",mime.getType(p)+"; charset=utf8");
           return fs.createReadStream(p,{start,end}).pipe(res)
        }

    }
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Range () The method of the request

range(req, res, statObj, p) {// Client Range:bytes=0-3 // Server accept-range :bytes Content-range :bytes 0-3/8777let range = req.headers['range']; // If there are scope requestsif (range) {
            let[, start, end] = range.match(/(\d*)-(\d*)/); Start = start? Number(start) : 0; //start sets the default value end = end? Number(end) :statObj.size - 1; //end Sets the default value res.statuscode = 206; // Request res.setheader ('Accept-Ranges'."bytes");
            res.setHeader('Content-Length',end-start+1);
            res.setHeader('Content-Range',`bytes ${start}-${end}/${statObj.size}`);
            return {start,end};
        }else {
            return {start:0, end:statObj.size}; }}Copy the code

Curl = curl = curl = curl = curl = curl

1. The content of TXT 123456789. We only want the first four characters

The test is perfect. Next we want to implement cGP-server, automatically open the browser, open the directory. We need to reference a module called yargs

7. Yargs module is configured with command line input

Yargs configuration usage ‘
Here we only use the most basic usage, a look to understand, see the official website for details

7.1 Functions of NPM Link

The NPM link command links an NPM package anywhere to the global execution environment so that it can be run directly from the command line anywhere.

7.2 Modifying the Package. json File

7.3 Configuration at www.js

7.3.1 We export the main app.js file to www.js for use

7.3.2 Modifying the www.js file

#! /usr/bin/env node // The bin/www.js command is executed
const yargs = require('yargs');
let argv = yargs.option('port',{// basic usage of yargsalias: 'p', // alias default: 3000, // Default value description:'this is port'// demand:false// Is it necessary to}).option('hostname', {alias: 'h',
    default: 'localhost',
    description:'this is hostname',
    demand:false
}).option('dir', {alias: 'd',
    default: process.cwd(),
    description:'this is cwd',
    demand:false
}).usage('cgp-server [options]').argv; // Start the servicelet Server = require('.. /src/app.js'); new Server(argv).start(); // Check whether the platform is Windows or MAClet platform = require('os').platform(); // Start the child processlet {exec} = require('child_process'); Win32 / / win systemif(platform==="win32") {exec(`start http://${argv.hostname}:${argv.port}`)}else {
    exec(`open http://${argv.hostname}:${argv.port}`)}Copy the code

A brief introduction to yargs usage. Then we type CPP-server –help to see the effect

yargs.option('port',{// basic usage of yargsalias: 'p', // alias default: 3000, // Default value description:'this is port'// demand:false// Must})Copy the code

To explain the process, start the service, then determine the system, and then automatically open the browser based on the platform

Let’s test it and see if it works

At the end

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How about HTTP in Node? Write your own ‘CPG-server’ static service

The preface

The preparatory work

Our catalog is deconstructed as follows

Start with the simplest config.js

The core code app.js

1. Introduce the required dependency packages

2. Enable the HTTP service

3. Implement the handleRequest method, which handles the request logic

File does not exist logic, sendError()

Ejs render directory list

6. File rendering method, this.sendFile() method

6.1 Adding the Cache Function

6.2 Enabling compression

6.3 Implement the range request function

7. Yargs module is configured with command line input

7.1 Functions of NPM Link

7.2 Modifying the Package. json File

7.3 Configuration at www.js

7.3.1 We export the main app.js file to www.js for use

7.3.2 Modifying the www.js file

At the end

How about HTTP in Node? Write your own ‘CPG-server’ static service

The preface

The preparatory work

Our catalog is deconstructed as follows

Start with the simplest config.js

The core code app.js

1. Introduce the required dependency packages

2. Enable the HTTP service

3. Implement the handleRequest method, which handles the request logic

File does not exist logic, sendError()

Ejs render directory list

6. File rendering method, this.sendFile() method

6.1 Adding the Cache Function

6.2 Enabling compression

6.3 Implement the range request function

7. Yargs module is configured with command line input

7.1 Functions of NPM Link

7.2 Modifying the Package. json File

7.3 Configuration at www.js

7.3.1 We export the main app.js file to www.js for use

7.3.2 Modifying the www.js file

At the end

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