How to use pure JavaScript to generate picture or slider CAPTCHA function for Node.JS
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There are some Node.JS picture generation libraries, such as node-captcha and so on, which require the cAccord Clipper + program to generate pictures. Cross-platform deployment is not very convenient. This paper introduces several picture CAPTCHA generation modules realized by pure JS.
Captchapng
CAPTCHA generation module realized by pure JavaScript.
Https://github.com/GeorgeChan/captchapng
Easy to install and less dependent:
Npm install captchapng
Example:
Var captchapng = require ('captchapng'); app.get (' / sign/captcha.png', function (req, res) {var captchaNumber = parseInt (Math.random () * 9000 + 1000) req.session.captcha = captchaNumbervar p = new captchapng (80 mine20, captchaNumber); / / width,height,numeric captchap.color (0,0,0,0); / / First color: background (red, green, blue, alpha) p.color (80,80,80,255) / / Second color: paint (red, green, blue, alpha) var img = p.getBase64 (); var imgbase64 = new Buffer (img,'base64'); res.writeHead (200,{ 'Content-Type':' image/png'}); res.end (imgbase64);})
Express + Captcha
CAPTCHA generation module designed for Express framework.
Https://github.com/napa3um/node-captcha
Installation & example:
$npm install captchaUsage (for Express 4) 'use strict'const express = require (' express') const session = require ('express-session') const bodyParser = require (' body-parser') const captchaUrl ='/ captcha.jpg'const captchaId = 'captcha'const captchaFieldName =' captcha'const captcha = require ('. / captcha'). Create ({cookie: captchaId}) const app = express () app.use (session ({secret: 'keyboard cat',resave: false,saveUninitialized: true) }) app.use (bodyParser.urlencoded ({extended: false})) app.get (captchaUrl, captcha.image ()) app.get ('/', (req, res) = > {res.type ('html') res.end (`
`)}) app.post ('/ login', (req, res) = > {res.type ('html') res.end (`
CAPTCHA VALID: ${captcha.check (req, req.body [captchaFieldName])}
`)}) app.listen (8080, () = > {console.log ('server started')})
Front-end slider verification
The front-end generation track is sent to the back-end verification, the input is simple, but it is easy to crack.
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