79 lines
3.9 KiB
Markdown
79 lines
3.9 KiB
Markdown
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# Detect if a string is a data URL
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[](https://travis-ci.org/killmenot/valid-data-url) [](https://coveralls.io/github/killmenot/valid-data-url?branch=master) [](https://david-dm.org/killmenot/valid-data-url) [](https://david-dm.org/killmenot/valid-data-url) [](https://www.npmjs.com/package/valid-data-url) [](https://www.npmjs.com/package/valid-data-url)
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Based on [Brian Grinstead](https://github.com/bgrins)'s solution https://gist.github.com/bgrins/6194623. Special thanks to [Jamie Davis](https://github.com/davisjam) for helping to fix [ReDoS](https://www.regular-expressions.info/redos.html) exploit.
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## Syntax
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The "data" URL scheme is described here [RFC2397](https://tools.ietf.org/html/rfc2397)
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dataurl := "data:" [ mediatype ] [ ";base64" ] "," data
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mediatype := [ type "/" subtype ] *( ";" parameter )
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data := *urlchar
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parameter := attribute "=" value
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where `urlchar` is imported from [RFC2396](https://www.ietf.org/rfc/rfc2045.txt), and `type`, `subtype`, `attribute` and `value` are the corresponding tokens from [RFC2045](https://www.ietf.org/rfc/rfc2045.txt), represented using URL escaped encoding of [RFC2396](https://www.ietf.org/rfc/rfc2396.txt) as necessary.
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Attribute values in [RFC2045](https://www.ietf.org/rfc/rfc2045.txt) are allowed to be either represented as tokens or as quoted strings. However, within a `data` URL, the `quoted-string` representation would be awkward, since the quote mark is itself not a valid urlchar. For this reason, parameter values should use the URL Escaped encoding instead of quoted string if the parameter values contain any `tspecial`.
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The `;base64` extension is distinguishable from a content-type parameter by the fact that it doesn't have a following `=` sign.
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## Install
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```
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npm install valid-data-url
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```
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## Example
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```javascript
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'use strict';
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var validDataUrl = require('valid-data-url');
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var isValid = validDataUrl('data:text/plain;base64,SGVsbG8sIFdvcmxkIQ%3D%3D'); // true
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```
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## People
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The original author is [Brian Grinstead](https://github.com/bgrins)
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## Contributors
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- [Gary Guagliardo Jr](https://github.com/guag)
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- [Steve Powell](https://github.com/steve-p-com)
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- [Rob Garrison](https://github.com/Mottie)
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- [Frank Tan](https://github.com/tansongyang)
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- [Jamie Davis](https://github.com/davisjam)
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- [Bogdan Chadkin](https://github.com/TrySound)
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- [Jon Ursenbach](https://github.com/erunion)
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## Licence
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The MIT License (MIT)
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Permission is hereby granted, free of charge, to any person obtaining a copy
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of this software and associated documentation files (the "Software"), to deal
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in the Software without restriction, including without limitation the rights
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to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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copies of the Software, and to permit persons to whom the Software is
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furnished to do so, subject to the following conditions:
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The above copyright notice and this permission notice shall be included in all
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copies or substantial portions of the Software.
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THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
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SOFTWARE.
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