The study of compression algorithms for WebSocket protocol

WebSocket protocol is a part of HTML5 standard, which is suitable for real-time and full duplex web applications such as online chat, notification server, and online game systems. A compression algorithm for WebSocket protocol has yet to be defined as a standard. There is a proposal to use Deflate algorithm, a lossless compression algorithm for WebSocket, but other compression algorithms are also available. In this paper, Deflate algorithm is compared with other lossless algorithms, i.e. Huffman, LZ77 and LZW algorithms in order to find a suitable compression algorithm for WebSocket protocol. A compression library is developed using JavaScript for studying and analyzing such compression algorithms for different data formats. In addition, an instant messaging system and an online game are developed and studied as the examples of WebSocket real-time and full duplex web applications. The performance metrics for this study are a compression ratio, compression and decompression speeds and overall time. In our experiments, the deflate compression algorithm gains the best result in terms of overall time and compression ratio for WebSocket protocol.