- Initial commit
This commit is contained in:
Timur Kozanov
253
Runtime/Implementations/Frames/WebSocketFrameReader.cs
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253
Runtime/Implementations/Frames/WebSocketFrameReader.cs
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#if !UNITY_WEBGL || UNITY_EDITOR
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using System;
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using System.Collections.Generic;
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using System.IO;
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using Best.HTTP.Shared;
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using Best.HTTP.Shared.Extensions;
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using Best.HTTP.Shared.PlatformSupport.Memory;
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using Best.HTTP.Shared.Streams;
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namespace Best.WebSockets.Implementations.Frames
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{
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/// <summary>
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/// Represents an incoming WebSocket Frame.
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/// </summary>
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public struct WebSocketFrameReader
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{
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#region Properties
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public byte Header { get; private set; }
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/// <summary>
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/// True if it's a final Frame in a sequence, or the only one.
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/// </summary>
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public bool IsFinal { get; private set; }
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/// <summary>
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/// The type of the Frame.
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/// </summary>
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public WebSocketFrameTypes Type { get; private set; }
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/// <summary>
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/// The decoded array of bytes.
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/// </summary>
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public BufferSegment Data { get; private set; }
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/// <summary>
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/// Textual representation of the received Data.
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/// </summary>
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public string DataAsText { get; private set; }
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#endregion
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#region Internal & Private Functions
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private static bool HasEnoughBytesForAFrame(PeekableIncomingSegmentStream peekable)
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{
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// https://www.rfc-editor.org/rfc/rfc6455#section-5.2
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// Minimum frame length is 2 bytes: header + zero length
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if (peekable.Length < 2)
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return false;
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peekable.BeginPeek();
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// header
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peekable.PeekByte();
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var maskAndLength = peekable.PeekByte();
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var length = (ulong)(maskAndLength & 127);
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if (length < 126)
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{
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return (ulong)peekable.Length >= (2 + length);
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}
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else if (length == 126)
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{
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return (ulong)peekable.Length >= (3 + length);
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}
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else if (length == 127)
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{
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return (ulong)peekable.Length >= (10 + length);
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}
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return true;
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}
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internal unsafe void Read(Stream stream)
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{
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// For the complete documentation for this section see:
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// http://tools.ietf.org/html/rfc6455#section-5.2
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this.Header = ReadByte(stream);
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// The first byte is the Final Bit and the type of the frame
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IsFinal = (this.Header & 0x80) != 0;
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Type = (WebSocketFrameTypes)(this.Header & 0xF);
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byte maskAndLength = ReadByte(stream);
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// The second byte is the Mask Bit and the length of the payload data
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if ((maskAndLength & 0x80) != 0)
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throw new NotImplementedException($"Payload from the server is masked!");
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// if 0-125, that is the payload length.
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var length = (UInt64)(maskAndLength & 127);
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// If 126, the following 2 bytes interpreted as a 16-bit unsigned integer are the payload length.
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if (length == 126)
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{
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byte[] rawLen = BufferPool.Get(2, true);
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stream.ReadBuffer(rawLen, 2);
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if (BitConverter.IsLittleEndian)
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Array.Reverse(rawLen, 0, 2);
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length = (UInt64)BitConverter.ToUInt16(rawLen, 0);
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BufferPool.Release(rawLen);
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}
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else if (length == 127)
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{
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// If 127, the following 8 bytes interpreted as a 64-bit unsigned integer (the
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// most significant bit MUST be 0) are the payload length.
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byte[] rawLen = BufferPool.Get(8, true);
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stream.ReadBuffer(rawLen, 8);
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if (BitConverter.IsLittleEndian)
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Array.Reverse(rawLen, 0, 8);
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length = (UInt64)BitConverter.ToUInt64(rawLen, 0);
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BufferPool.Release(rawLen);
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}
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if (length == 0L)
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{
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Data = BufferSegment.Empty;
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return;
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}
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var buffer = BufferPool.Get((long)length, true);
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uint readLength = 0;
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try
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{
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do
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{
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int read = stream.Read(buffer, (int)readLength, (int)(length - readLength));
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if (read <= 0)
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throw ExceptionHelper.ServerClosedTCPStream();
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readLength += (uint)read;
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} while (readLength < length);
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}
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catch
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{
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BufferPool.Release(buffer);
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throw;
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}
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this.Data = new BufferSegment(buffer, 0, (int)length);
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}
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private static byte ReadByte(Stream stream)
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{
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int read = stream.ReadByte();
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if (read < 0)
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throw ExceptionHelper.ServerClosedTCPStream();
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return (byte)read;
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}
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#endregion
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#region Public Functions
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/// <summary>
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/// Assembles all fragments into a final frame. Call this on the last fragment of a frame.
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/// </summary>
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/// <param name="fragments">The list of previously downloaded and parsed fragments of the frame</param>
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public void Assemble(List<WebSocketFrameReader> fragments)
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{
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// this way the following algorithms will handle this fragment's data too
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fragments.Add(this);
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UInt64 finalLength = 0;
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for (int i = 0; i < fragments.Count; ++i)
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finalLength += (UInt64)fragments[i].Data.Count;
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byte[] buffer = BufferPool.Get((long)finalLength, true);
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UInt64 pos = 0;
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for (int i = 0; i < fragments.Count; ++i)
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{
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if (fragments[i].Data.Count > 0)
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Array.Copy(fragments[i].Data.Data, fragments[i].Data.Offset, buffer, (int)pos, (int)fragments[i].Data.Count);
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fragments[i].ReleaseData();
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pos += (UInt64)fragments[i].Data.Count;
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}
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// All fragments of a message are of the same type, as set by the first fragment's opcode.
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this.Type = fragments[0].Type;
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// Reserver flags may be contained only in the first fragment
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this.Header = fragments[0].Header;
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this.Data = new BufferSegment(buffer, 0, (int)finalLength);
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}
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/// <summary>
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/// This function will decode the received data incrementally with the associated websocket's extensions.
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/// </summary>
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public void DecodeWithExtensions(WebSocket webSocket)
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{
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if (webSocket.Extensions != null)
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for (int i = 0; i < webSocket.Extensions.Length; ++i)
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{
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var ext = webSocket.Extensions[i];
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if (ext != null)
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{
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var newData = ext.Decode(this.Header, this.Data);
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if (this.Data != newData)
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{
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this.ReleaseData();
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this.Data = newData;
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}
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}
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}
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if (this.Type == WebSocketFrameTypes.Text)
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{
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if (this.Data != BufferSegment.Empty)
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{
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this.DataAsText = System.Text.Encoding.UTF8.GetString(this.Data.Data, this.Data.Offset, this.Data.Count);
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this.ReleaseData();
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}
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else
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HTTPManager.Logger.Warning("WebSocketFrameReader", "Empty Text frame received!");
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}
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}
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public void ReleaseData()
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{
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BufferPool.Release(this.Data);
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this.Data = BufferSegment.Empty;
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}
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public override string ToString()
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{
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return string.Format("[{0} Header: {1:X2}, IsFinal: {2}, Data: {3}]", this.Type.ToString(), this.Header, this.IsFinal, this.Data);
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}
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#endregion
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}
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}
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#endif
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