The WebSocket protocol establishes a two-way communication channel via TCP.
Messages are made up of one or more dataframes, and are delineated by
frames with the fin bit set.
This page hosts a formal specification of WebSocket using Kaitai Struct. This specification can be automatically translated into a variety of programming languages to get a parsing library.
All parsing code for C# generated by Kaitai Struct depends on the C# runtime library. You have to install it before you can parse data.
The C# runtime library is available in the NuGet Gallery. Installation instructions can also be found there.
Parse a local file and get structure in memory:
var data = Websocket.FromFile("path/to/local/file.bin");
Or parse structure from a byte array:
byte[] someArray = new byte[] { ... };
var data = new Websocket(new KaitaiStream(someArray));
After that, one can get various attributes from the structure by accessing properties like:
data.InitialFrame // => get initial frame
// This is a generated file! Please edit source .ksy file and use kaitai-struct-compiler to rebuild
using System.Collections.Generic;
namespace Kaitai
{
/// <summary>
/// The WebSocket protocol establishes a two-way communication channel via TCP.
/// Messages are made up of one or more dataframes, and are delineated by
/// frames with the `fin` bit set.
/// </summary>
public partial class Websocket : KaitaiStruct
{
public static Websocket FromFile(string fileName)
{
return new Websocket(new KaitaiStream(fileName));
}
public enum Opcode
{
Continuation = 0,
Text = 1,
Binary = 2,
Reserved3 = 3,
Reserved4 = 4,
Reserved5 = 5,
Reserved6 = 6,
Reserved7 = 7,
Close = 8,
Ping = 9,
Pong = 10,
ReservedControlB = 11,
ReservedControlC = 12,
ReservedControlD = 13,
ReservedControlE = 14,
ReservedControlF = 15,
}
public Websocket(KaitaiStream p__io, KaitaiStruct p__parent = null, Websocket p__root = null) : base(p__io)
{
m_parent = p__parent;
m_root = p__root ?? this;
_read();
}
private void _read()
{
_initialFrame = new InitialFrame(m_io, this, m_root);
if (InitialFrame.Header.Finished != true) {
_trailingFrames = new List<Dataframe>();
{
var i = 0;
Dataframe M_;
do {
M_ = new Dataframe(m_io, this, m_root);
_trailingFrames.Add(M_);
i++;
} while (!(M_.Header.Finished));
}
}
}
public partial class FrameHeader : KaitaiStruct
{
public static FrameHeader FromFile(string fileName)
{
return new FrameHeader(new KaitaiStream(fileName));
}
public FrameHeader(KaitaiStream p__io, KaitaiStruct p__parent = null, Websocket p__root = null) : base(p__io)
{
m_parent = p__parent;
m_root = p__root;
f_lenPayload = false;
_read();
}
private void _read()
{
_finished = m_io.ReadBitsIntBe(1) != 0;
_reserved = m_io.ReadBitsIntBe(3);
_opcode = ((Websocket.Opcode) m_io.ReadBitsIntBe(4));
_isMasked = m_io.ReadBitsIntBe(1) != 0;
_lenPayloadPrimary = m_io.ReadBitsIntBe(7);
m_io.AlignToByte();
if (LenPayloadPrimary == 126) {
_lenPayloadExtended1 = m_io.ReadU2be();
}
if (LenPayloadPrimary == 127) {
_lenPayloadExtended2 = m_io.ReadU4be();
}
if (IsMasked) {
_maskKey = m_io.ReadU4be();
}
}
private bool f_lenPayload;
private int _lenPayload;
public int LenPayload
{
get
{
if (f_lenPayload)
return _lenPayload;
_lenPayload = (int) ((LenPayloadPrimary <= 125 ? LenPayloadPrimary : (LenPayloadPrimary == 126 ? LenPayloadExtended1 : LenPayloadExtended2)));
f_lenPayload = true;
return _lenPayload;
}
}
private bool _finished;
private ulong _reserved;
private Opcode _opcode;
private bool _isMasked;
private ulong _lenPayloadPrimary;
private ushort? _lenPayloadExtended1;
private uint? _lenPayloadExtended2;
private uint? _maskKey;
private Websocket m_root;
private KaitaiStruct m_parent;
public bool Finished { get { return _finished; } }
public ulong Reserved { get { return _reserved; } }
public Opcode Opcode { get { return _opcode; } }
public bool IsMasked { get { return _isMasked; } }
public ulong LenPayloadPrimary { get { return _lenPayloadPrimary; } }
public ushort? LenPayloadExtended1 { get { return _lenPayloadExtended1; } }
public uint? LenPayloadExtended2 { get { return _lenPayloadExtended2; } }
public uint? MaskKey { get { return _maskKey; } }
public Websocket M_Root { get { return m_root; } }
public KaitaiStruct M_Parent { get { return m_parent; } }
}
public partial class InitialFrame : KaitaiStruct
{
public static InitialFrame FromFile(string fileName)
{
return new InitialFrame(new KaitaiStream(fileName));
}
public InitialFrame(KaitaiStream p__io, Websocket p__parent = null, Websocket p__root = null) : base(p__io)
{
m_parent = p__parent;
m_root = p__root;
_read();
}
private void _read()
{
_header = new FrameHeader(m_io, this, m_root);
if (Header.Opcode != Websocket.Opcode.Text) {
_payloadBytes = m_io.ReadBytes(Header.LenPayload);
}
if (Header.Opcode == Websocket.Opcode.Text) {
_payloadText = System.Text.Encoding.GetEncoding("UTF-8").GetString(m_io.ReadBytes(Header.LenPayload));
}
}
private FrameHeader _header;
private byte[] _payloadBytes;
private string _payloadText;
private Websocket m_root;
private Websocket m_parent;
public FrameHeader Header { get { return _header; } }
public byte[] PayloadBytes { get { return _payloadBytes; } }
public string PayloadText { get { return _payloadText; } }
public Websocket M_Root { get { return m_root; } }
public Websocket M_Parent { get { return m_parent; } }
}
public partial class Dataframe : KaitaiStruct
{
public static Dataframe FromFile(string fileName)
{
return new Dataframe(new KaitaiStream(fileName));
}
public Dataframe(KaitaiStream p__io, Websocket p__parent = null, Websocket p__root = null) : base(p__io)
{
m_parent = p__parent;
m_root = p__root;
_read();
}
private void _read()
{
_header = new FrameHeader(m_io, this, m_root);
if (M_Root.InitialFrame.Header.Opcode != Websocket.Opcode.Text) {
_payloadBytes = m_io.ReadBytes(Header.LenPayload);
}
if (M_Root.InitialFrame.Header.Opcode == Websocket.Opcode.Text) {
_payloadText = System.Text.Encoding.GetEncoding("UTF-8").GetString(m_io.ReadBytes(Header.LenPayload));
}
}
private FrameHeader _header;
private byte[] _payloadBytes;
private string _payloadText;
private Websocket m_root;
private Websocket m_parent;
public FrameHeader Header { get { return _header; } }
public byte[] PayloadBytes { get { return _payloadBytes; } }
public string PayloadText { get { return _payloadText; } }
public Websocket M_Root { get { return m_root; } }
public Websocket M_Parent { get { return m_parent; } }
}
private InitialFrame _initialFrame;
private List<Dataframe> _trailingFrames;
private Websocket m_root;
private KaitaiStruct m_parent;
public InitialFrame InitialFrame { get { return _initialFrame; } }
public List<Dataframe> TrailingFrames { get { return _trailingFrames; } }
public Websocket M_Root { get { return m_root; } }
public KaitaiStruct M_Parent { get { return m_parent; } }
}
}