Node.JS用纯JavaScript生成图片或滑块式验证码

captchapng

npm install captchapng

var captchapng = require('captchapng');

app.get('/sign/captcha.png', function(req, res) {
  var captchaNumber   = parseInt(Math.random() * 9000 + 1000)

  req.session.captcha = captchaNumber

  var p = new captchapng(80,20, captchaNumber); // width,height,numeric captcha
  p.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

$ npm install captcha

Usage (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(`
        <img src="${ captchaUrl }"/>
        <form action="/login" method="post">
            <input type="text" name="${ captchaFieldName }"/>
            <input type="submit"/>
        </form>
    `)
})

app.post('/login', (req, res) => {
    res.type('html')
    res.end(`
        <p>CAPTCHA VALID: ${ captcha.check(req, req.body[captchaFieldName]) }</p>
    `)
})

app.listen(8080, () => {
    console.log('server started')
})

前端滑块验证