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README.md

canvas-captcha

Build Status

a captcha module for nodejs based on node-canvas

note

  • install Cairo first, For system-specific installation view the Wiki from node-canvas
  • if you can see the captcha image, but empty, try another font your server has or install proper font pack in your server, such as sudo apt-get install ttf-mscorefonts-installer.

Installation

npm install canvas-captcha

use

//captcha 
let captcha = require('canvas-captcha')
let captchaOptions = {
  charPool: ('abcdefghijklmnopqrstuvwxyz' + 'abcdefghijklmnopqrstuvwxyz'.toUpperCase() + '1234567890').split('') //char pool Array
  ,size: {
    width: 100
    ,height: 32
  } //image size
  ,textPos: {
    left: 15
    ,top: 26
  } //text drawing start position
  ,rotate: .01 //text ratate
  ,charLength: 4 //how many chars
  ,font: '26px Unifont' //font size
  ,strokeStyle: '#0088cc' //style
  ,bgColor: '#eeeeee' //bg color
  ,confusion: true //draw another group background text to mangle the text
  ,cFont: '30px Arial' //bg text style
  ,cStrokeStyle: '#adc' //bg text color
  ,cRotate: -.05 //bg text rotate
}

//callback style
app.get('/captcha', function(req, res) {
  captcha(captchaOptions, function(err, data) {
    if(err) {
      res.send(err)
    }
    else {
      req.session.captcha = data.captchaStr
      res.end(data.captchaImg)
    }
  })
})

//use promise
let captchaPromise = function(options) {
  return new Promise(function(resolve, reject) {
    captcha(options, function(err, data) {
      if(err) reject(err)
      else resolve(data)
    })
  })
}

//in express
app.get('/captcha', function(req, res) {

  captchaPromise(captchaOptions)
  .then(function(data) {
    req.session.captcha = data.captchaStr
    res.end(data.captchaImg)
  }, function(err) {
    res.send(err)
  })

})

//in koa
app.get('/captcha', function* (next) {

  var data = yield captchaPromise(captchaOptions)
  this.session.captcha = data.captchaStr
  this.body = data.captchaImg

})

//or
app.get('/captcha', async ctx => {

  let data = await captchaPromise(captchaOptions)
  ctx.session.captcha = data.captchaStr
  ctx.body = data.captchaImg

})

test && example

git clone https://github.com/zxdong262/canvas-captcha.git
cd canvas-captcha
sudo npm install

# test
npm run test

# example
node test/app.js
# then visit http://127.0.0.1:5001

changelog

  • 2.1.0 use canvas 1.3.15, support node 6.2+
  • 2.0.1 use canvas 1.3.12, a little rewrite
  • 2.0.0 use canvas 1.2.9, compatible with nodejs v4
  • 1.2.8 use 'Unifont' as default font
  • 1.2.7 use 'system' as default font
  • 1.2.6 just fix readme koa example
  • 1.2.5 add some example to readme, use canvas version 1.2.1
  • 1.2.4 make err the first callback param
  • 1.2.3 use canvas version 1.1.6 version instead of version *

license

MIT

About

A simple captcha module for nodejs based on node-canvas

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