57 lines
1.3 KiB
JavaScript
57 lines
1.3 KiB
JavaScript
'use strict';
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var ProbeError = require('./lib/common').ProbeError;
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var parsers = require('./lib/parsers_stream');
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var PassThrough = require('stream').PassThrough;
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module.exports = function probeStream(stream) {
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var proxy = new PassThrough();
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var cnt = 0; // count of working parsers
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var result = new Promise(function (resolve, reject) {
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stream.on('error', reject);
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proxy.on('error', reject);
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function nope() {}
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function parserEnd() {
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proxy.unpipe(this);
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this.removeAllListeners();
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cnt--;
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// if all parsers finished without success -> fail.
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if (!cnt) reject(new ProbeError('unrecognized file format', 'ECONTENT'));
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}
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Object.keys(parsers).forEach(function (type) {
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var pStream = parsers[type]();
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cnt++;
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pStream.once('data', resolve);
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pStream.once('end', parserEnd);
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// silently ignore errors because user does not need to know
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// that something wrong is happening here
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pStream.on('error', nope);
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proxy.pipe(pStream);
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});
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});
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function cleanup() {
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// request stream doesn't have unpipe, https://github.com/request/request/issues/874
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if (typeof stream.unpipe === 'function') stream.unpipe(proxy);
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proxy.end();
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}
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result.then(cleanup).catch(cleanup);
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stream.pipe(proxy);
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return result;
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};
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module.exports.parsers = parsers;
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