GZip Examples

GZip.cs

public static IEnumerable<string> Compress(this IEnumerable<string> stream)
        {
            foreach (var message in stream)
            {
                // this string compression code is lifted & modified from 
                // http://madskristensen.net/post/Compress-and-decompress-strings-in-C
                var buffer = Encoding.UTF8.GetBytes(message);
                var ms = new MemoryStream();
                using (var zip = new GZipStream(ms, CompressionMode.Compress, true))
                {
                    zip.Write(buffer, 0, buffer.Length);
                }

                ms.Position = 0;
                var compressed = new byte[ms.Length];
                ms.Read(compressed, 0, compressed.Length);

                var gzBuffer = new byte[compressed.Length + 4];
                Buffer.BlockCopy(compressed, 0, gzBuffer, 4, compressed.Length);
                Buffer.BlockCopy(BitConverter.GetBytes(buffer.Length), 0, gzBuffer, 0, 4);

                yield return Convert.ToBase64String(gzBuffer);
            }
        }

GZip.fs

//http://madskristensen.net/post/Compress-and-decompress-strings-in-C

let compress (data : string) = 
    let buffer = Encoding.UTF8.GetBytes(data)
    let ms = new MemoryStream()
    (   use zip = new GZipStream(ms, CompressionMode.Compress, true)
        zip.Write(buffer, 0, buffer.Length) )
    ms.Position <- 0L
    let compressed = Array.zeroCreate<byte> (int(ms.Length))
    ms.Read(compressed, 0, compressed.Length) |> ignore
    let gzipBuffer = Array.zeroCreate<byte> (int(compressed.Length) + 4)
    Buffer.BlockCopy(compressed, 0, gzipBuffer, 4, compressed.Length)
    Buffer.BlockCopy(BitConverter.GetBytes(buffer.Length), 0, gzipBuffer, 0, 4)
    Convert.ToBase64String gzipBuffer

let decompress (data : string) = 
    let gzipBuffer = Convert.FromBase64String(data)
    (   use memoryStream = new MemoryStream()
        let dataLength = BitConverter.ToInt32(gzipBuffer, 0)
        memoryStream.Write(gzipBuffer, 4, gzipBuffer.Length - 4)
        let buffer = Array.zeroCreate<byte> (int(dataLength))
        memoryStream.Position <- 0L
        (   use zip = new GZipStream(memoryStream, CompressionMode.Decompress)
            zip.Read(buffer, 0, buffer.Length) |> ignore)
        Encoding.UTF8.GetString(buffer)
    )

GZip.js

function compress(message) {
        var data = Buffer.from(message).toString();
        var self = this;
        zlib.gzip(data, function(err, compressed){
            if(!err){ 
                // add message data.
                var target = Buffer.alloc(compressed.length + 4)
                compressed.copy(target, 4, 0, compressed.length)

                // add header data
                var compressedLength = compressed.length.toString()
                var compLen = Buffer.from(compressedLength);
                compLen.copy(target, 0, 0, 4)

                // send message
                return new Uint8Array(Buffer.from(target.toString('base64')));
            }else{
                throw new Error('Error running gzip compression for data blob: %s', data);
            }
            
        });
        
    }

function decompress(input){
    var buffer =  Buffer.from(input, 'base64').slice(4);
        
    zlib.gunzip(buffer, (err, buffer) => {
        if (!err) {
            var decompressed = buffer.toString('utf-8');

        } else {
            context.log(err);// handle error
        }
    });
}