29 lines
		
	
	
		
			681 B
		
	
	
	
		
			JavaScript
		
	
	
	
	
	
			
		
		
	
	
			29 lines
		
	
	
		
			681 B
		
	
	
	
		
			JavaScript
		
	
	
	
	
	
"use strict";
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import stream from "stream";
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class ZlibHeaderTransformStream extends stream.Transform {
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  __transform(chunk, encoding, callback) {
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    this.push(chunk);
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    callback();
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  }
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  _transform(chunk, encoding, callback) {
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    if (chunk.length !== 0) {
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      this._transform = this.__transform;
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      // Add Default Compression headers if no zlib headers are present
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      if (chunk[0] !== 120) { // Hex: 78
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        const header = Buffer.alloc(2);
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        header[0] = 120; // Hex: 78
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        header[1] = 156; // Hex: 9C 
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        this.push(header, encoding);
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      }
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    }
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    this.__transform(chunk, encoding, callback);
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  }
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}
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export default ZlibHeaderTransformStream;
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