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74 lines
1.8 KiB
74 lines
1.8 KiB
'use strict';
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var Snappy = require('../connection/utils').retrieveSnappy(),
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zlib = require('zlib');
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var compressorIDs = {
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snappy: 1,
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zlib: 2
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};
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var uncompressibleCommands = [
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'ismaster',
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'saslStart',
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'saslContinue',
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'getnonce',
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'authenticate',
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'createUser',
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'updateUser',
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'copydbSaslStart',
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'copydbgetnonce',
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'copydb'
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];
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// Facilitate compressing a message using an agreed compressor
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var compress = function(self, dataToBeCompressed, callback) {
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switch (self.options.agreedCompressor) {
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case 'snappy':
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Snappy.compress(dataToBeCompressed, callback);
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break;
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case 'zlib':
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// Determine zlibCompressionLevel
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var zlibOptions = {};
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if (self.options.zlibCompressionLevel) {
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zlibOptions.level = self.options.zlibCompressionLevel;
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}
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zlib.deflate(dataToBeCompressed, zlibOptions, callback);
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break;
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default:
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throw new Error(
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'Attempt to compress message using unknown compressor "' +
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self.options.agreedCompressor +
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'".'
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);
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}
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};
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// Decompress a message using the given compressor
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var decompress = function(compressorID, compressedData, callback) {
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if (compressorID < 0 || compressorID > compressorIDs.length) {
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throw new Error(
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'Server sent message compressed using an unsupported compressor. (Received compressor ID ' +
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compressorID +
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')'
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);
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}
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switch (compressorID) {
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case compressorIDs.snappy:
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Snappy.uncompress(compressedData, callback);
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break;
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case compressorIDs.zlib:
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zlib.inflate(compressedData, callback);
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break;
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default:
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callback(null, compressedData);
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}
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};
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module.exports = {
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compressorIDs: compressorIDs,
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uncompressibleCommands: uncompressibleCommands,
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compress: compress,
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decompress: decompress
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};
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