canvas-captcha

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 
var captcha = require('canvas-captcha')
,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
var 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
 
})
 
 

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