Websocket protocol for binary message

Hi Guys, i’m trying to reproduce the protocol for Binary message to use with my custom websocket code in Xamarin since the SDK doesn’t work there.

below is the code i’m using to create the header

public struct WSHeader
    {
        public string Path;
        public string XRequestId;
        public string XTimestamp;
        public string ContentType;
    }

public static int GetHeaderSize(WSHeader header)
        {
            var str = "";
            str += header.Path;
            str += header.XRequestId;
            str += header.XTimestamp;
            str += header.ContentType;
            return str.Length;
        }

 public static WSHeader makeAudioHeaders(string type, string reqId)
        {
            var header = new WSHeader()
            {
                Path = $"path:{type}\r\n",
                XRequestId = $"x-requestid:{reqId}\r\n",
                XTimestamp = $"x-timestamp:{DateTime.UtcNow.ToString("o", System.Globalization.CultureInfo.InvariantCulture)}\r\n"
            };
            return header;
        }

Then i write to the stream giving the 2 byte header length value

public static void WriteHeaderToStream(Stream stream, string type, Func<WSHeader> makeHeader)
        {
            var header = makeHeader();
            Encoding encoding = type == "audio" ? Encoding.ASCII : Encoding.UTF8;
            using (var writer = new BinaryWriter(stream, encoding, true))
            {
                if (type == "audio")
                {
                    writer.Write($"{(short)GetHeaderSize(header)}\r\n"); // i also tried without '\r\n'
                    // writer.Write((short)GetHeaderSize(header)); // this doesn't work for some reason
                }

                writer.Write(encoding.GetBytes(header.Path));
                writer.Write(encoding.GetBytes(header.XRequestId));
                writer.Write(encoding.GetBytes(header.XTimestamp));
                writer.Write(encoding.GetBytes(header.ContentType));

                writer.Write(encoding.GetBytes("\r\n"));
            }
        }

The turn.start works and gives me the below (my console is printing the requestId all weird)

X-RequestId:6666666666664666A666666666666668
Content-Type:application/json; charset=utf-8
Path:turn.start

{
  "context": {
    "serviceTag": "9c3e3a3565f64cc8b0d099952e9546ab"
  }
}

After that, i get this error for subsequent requests, i think i’m not writing the header to the stream properly, i’m new to C#, could anyone help me please ?

[0:] Status Code InvalidPayloadData
[0:] Status Code Description Incorrect message format. Binary message has invalid header size

p.s. this is all spaghetti code for now until i get this working.

[rhurey]

BinaryWriter.Write(Int16) is documented to write little endian.

https://docs.microsoft.com/en-us/dotnet/api/system.io.binarywriter.write

So it reversed the bytes on you. By writing only one byte you didn’t give it any choice.

A decent article on endianness: https://en.m.wikipedia.org/wiki/Endianness

[jhakulin]

Closing this issue with the note that Xamarin support is being worked on currently and targeted to be available in the coming speech SDK release.