56 lines
1.4 KiB
JavaScript
56 lines
1.4 KiB
JavaScript
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'use strict';
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/**
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* Module exports.
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*/
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module.exports = dataUriToBuffer;
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/**
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* Returns a `Buffer` instance from the given data URI `uri`.
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*
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* @param {String} uri Data URI to turn into a Buffer instance
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* @return {Buffer} Buffer instance from Data URI
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* @api public
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*/
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function dataUriToBuffer (uri) {
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if (!/^data\:/i.test(uri)) {
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throw new TypeError('`uri` does not appear to be a Data URI (must begin with "data:")');
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}
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// strip newlines
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uri = uri.replace(/\r?\n/g, '');
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// split the URI up into the "metadata" and the "data" portions
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var firstComma = uri.indexOf(',');
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if (-1 === firstComma || firstComma <= 4) throw new TypeError('malformed data: URI');
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// remove the "data:" scheme and parse the metadata
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var meta = uri.substring(5, firstComma).split(';');
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var base64 = false;
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var charset = 'US-ASCII';
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for (var i = 0; i < meta.length; i++) {
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if ('base64' == meta[i]) {
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base64 = true;
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} else if (0 == meta[i].indexOf('charset=')) {
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charset = meta[i].substring(8);
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}
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}
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// get the encoded data portion and decode URI-encoded chars
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var data = unescape(uri.substring(firstComma + 1));
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var encoding = base64 ? 'base64' : 'ascii';
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var buffer = new Buffer(data, encoding);
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// set `.type` property to MIME type
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buffer.type = meta[0] || 'text/plain';
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// set the `.charset` property
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buffer.charset = charset;
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return buffer;
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}
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