63 lines
1.4 KiB
JavaScript
63 lines
1.4 KiB
JavaScript
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/**
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* Module dependencies.
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*/
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var crypto = require('crypto');
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var Readable = require('readable-stream');;
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var dataUriToBuffer = require('data-uri-to-buffer');
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var NotModifiedError = require('./notmodified');
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var debug = require('debug')('get-uri:data');
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/**
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* Module exports.
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*/
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module.exports = get;
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/**
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* Returns a Readable stream from a "data:" URI.
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*
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* @api protected
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*/
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function get (parsed, opts, fn) {
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var uri = parsed.href;
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var cache = opts.cache;
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// need to create a SHA1 hash of the URI string, for cacheability checks
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// in future `getUri()` calls with the same data URI passed in.
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var shasum = crypto.createHash('sha1');
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shasum.update(uri);
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var hash = shasum.digest('hex');
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debug('generated SHA1 hash for "data:" URI: %o', hash);
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// check if the cache is the same "data:" URI that was previously passed in.
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if (cache && cache.hash == hash) {
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debug('got matching cache SHA1 hash: %o', hash);
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fn(new NotModifiedError());
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} else {
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debug('creating Readable stream from "data:" URI buffer');
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var buf = dataUriToBuffer(uri, opts);
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var rs = new Readable();
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rs._read = read(buf);
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buf = null;
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rs.hash = hash;
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fn(null, rs);
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}
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}
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/**
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* Function that returns a Readable `_read` function implementation.
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*
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* @api private
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*/
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function read (buf) {
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return function (n) {
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this.push(buf);
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this.push(null);
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buf = null;
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};
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}
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