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124 lines
3.8 KiB
124 lines
3.8 KiB
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<div align="center">
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[](https://travis-ci.org/lemonce/svg-captcha)
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[](https://www.npmjs.com/package/svg-captcha)
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[](https://www.npmjs.com/package/svg-captcha)
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</div>
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> generate svg captcha in node.js
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## Translations
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[中文](README_CN.md)
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## useful if you
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- cannot or do not want to use google recaptcha
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- have issue with install c++ addon
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## install
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```
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npm install --save svg-captcha
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```
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## usage
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```Javascript
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var svgCaptcha = require('svg-captcha');
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var captcha = svgCaptcha.create();
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console.log(captcha);
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// {data: '<svg.../svg>', text: 'abcd'}
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```
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with express
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```Javascript
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var svgCaptcha = require('svg-captcha');
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app.get('/captcha', function (req, res) {
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var captcha = svgCaptcha.create();
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req.session.captcha = captcha.text;
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res.type('svg');
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res.status(200).send(captcha.data);
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});
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```
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## API
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#### `svgCaptcha.create(options)`
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If no option is passed, you will get a random string of four characters and corresponding svg.
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* `size`: 4 // size of random string
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* `ignoreChars`: '0o1i' // filter out some characters like 0o1i
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* `noise`: 1 // number of noise lines
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* `color`: true // characters will have distinct colors instead of grey, true if background option is set
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* `background`: '#cc9966' // background color of the svg image
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This function returns an object that has the following property:
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* `data`: string // svg path data
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* `text`: string // captcha text
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#### `svgCaptcha.createMathExpr(options)`
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Similar to create api, you have the above options plus 3 additional:
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* `mathMin`: 1 // the minimum value the math expression can be
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* `mathMax`: 9 // the maximum value the math expression can be
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* `mathOperator`: + // The operator to use, `+`, `-` or `+-` (for random `+` or `-`)
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This function returns an object that has the following property:
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* `data`: string // svg of the math expression
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* `text`: string // the answer of the math expression
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#### `svgCaptcha.loadFont(url)`
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Load your own font and override the default font.
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* `url`: string // path to your font
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This api is a wrapper around loadFont api of opentype.js.
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Your may need experiment around various options to make your own font accessible.
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See the following api.
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#### `svgCaptcha.options`
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Gain access to global setting object.
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It is used for create and createMathExpr api as the default options.
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In addition to size, noise, color, and background, you can also set the following property:
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* `width`: number // width of captcha
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* `height`: number // height of captcha
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* `fontSize`: number // captcha text size
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* `charPreset`: string // random character preset
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#### `svgCaptcha.randomText([size|options])`
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return a random string.
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#### `svgCaptcha(text, options)`
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return a svg captcha based on text provided.
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In pre 1.1.0 version you have to call these two functions,
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now you can call create() to save some key strokes ;).
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## sample image
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default captcha image:
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math expression image with color options:
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## why use svg?
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It does not require any c++ addon.
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The result image is smaller than jpeg image.
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> This has to be a joke. /\<text.+\>;.+\<\/text\>/g.test...
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svg captcha uses opentype.js underneath, which means that there is no
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'<text>1234</text>'.
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You get
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'<path fill="#444" d="M104.83 19.74L107.85 19.74L112 33.56L116.13 19.74L119.15 19.74L113.48 36.85...'
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instead.
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Even though you can write a program that convert svg to png, svg captcha has done its job
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—— make captcha recognition harder
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## License
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[MIT](LICENSE.md)
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