#if (!UNITY_WEBGL || UNITY_EDITOR) && !BESTHTTP_DISABLE_ALTERNATE_SSL && !BESTHTTP_DISABLE_HTTP2
using System;
using System.Collections.Generic;
using System.Threading;
using System.Collections.Concurrent;
using BestHTTP.Extensions;
using BestHTTP.Core;
using BestHTTP.PlatformSupport.Memory;
namespace BestHTTP.Connections.HTTP2
{
public sealed class HTTP2Handler : IHTTPRequestHandler
{
public bool HasCustomRequestProcessor { get { return true; } }
public KeepAliveHeader KeepAlive { get { return null; } }
public bool CanProcessMultiple { get { return this.goAwaySentAt == DateTime.MaxValue && this.isRunning; } }
// Connection preface starts with the string PRI * HTTP/2.0\r\n\r\nSM\r\n\r\n).
private static readonly byte[] MAGIC = new byte[24] { 0x50, 0x52, 0x49, 0x20, 0x2a, 0x20, 0x48, 0x54, 0x54, 0x50, 0x2f, 0x32, 0x2e, 0x30, 0x0d, 0x0a, 0x0d, 0x0a, 0x53, 0x4d, 0x0d, 0x0a, 0x0d, 0x0a };
public const UInt32 MaxValueFor31Bits = 0xFFFFFFFF >> 1;
public double Latency { get; private set; }
private DateTime lastPingSent = DateTime.MinValue;
private TimeSpan pingFrequency = TimeSpan.FromMinutes(5);
public static int RTTBufferCapacity = 5;
private CircularBuffer<double> rtts = new CircularBuffer<double>(RTTBufferCapacity);
private volatile bool isThreadsStarted;
private volatile bool isRunning;
private AutoResetEvent newFrameSignal = new AutoResetEvent(false);
private ConcurrentQueue<HTTPRequest> requestQueue = new ConcurrentQueue<HTTPRequest>();
private List<HTTP2Stream> clientInitiatedStreams = new List<HTTP2Stream>();
private HPACKEncoder HPACKEncoder;
private ConcurrentQueue<HTTP2FrameHeaderAndPayload> newFrames = new ConcurrentQueue<HTTP2FrameHeaderAndPayload>();
private List<HTTP2FrameHeaderAndPayload> outgoingFrames = new List<HTTP2FrameHeaderAndPayload>();
private HTTP2SettingsManager settings = new HTTP2SettingsManager();
private UInt32 remoteWindow;
private DateTime lastInteraction;
private DateTime goAwaySentAt = DateTime.MaxValue;
private HTTPConnection conn;
private int threadExitCount;
private TimeSpan MaxGoAwayWaitTime { get { return this.goAwaySentAt == DateTime.MaxValue ? TimeSpan.MaxValue : TimeSpan.FromMilliseconds(Math.Max(this.Latency * 2.5, 1500)); } }
public HTTP2Handler(HTTPConnection conn)
{
this.conn = conn;
this.isRunning = true;
// Put the first request to the queue
this.requestQueue.Enqueue(conn.CurrentRequest);
}
public void Process(HTTPRequest request)
{
HTTPManager.Logger.Information("HTTP2Handler", "Process request called");
this.lastInteraction = DateTime.UtcNow;
this.requestQueue.Enqueue(request);
this.newFrameSignal.Set();
}
public void RunHandler()
{
HTTPManager.Logger.Information("HTTP2Handler", "Processing thread up and running!");
Thread.CurrentThread.Name = "HTTP2 Process";
PlatformSupport.Threading.ThreadedRunner.RunLongLiving(ReadThread);
try
{
bool atLeastOneStreamHasAFrameToSend = true;
this.HPACKEncoder = new HPACKEncoder(this.settings);
// https://httpwg.org/specs/rfc7540.html#InitialWindowSize
// The connection flow-control window is also 65,535 octets.
this.remoteWindow = this.settings.RemoteSettings[HTTP2Settings.INITIAL_WINDOW_SIZE];
// we want to pack as many data as we can in one tcp segment, but setting the buffer's size too high
// we might keep data too long and send them in bursts instead of in a steady stream.
// Keeping it too low might result in a full tcp segment and one with very low payload
// Is it possible that one full tcp segment sized buffer would be the best, or multiple of it.
// It would keep the network busy without any fragments. The ethernet layer has a maximum of 1500 bytes,
// but there's two layers of 20 byte headers each, so as a theoretical maximum it's 1500-20-20 bytes.
// On the other hand, if the buffer is small (1-2), that means that for larger data, we have to do a lot
// of system calls, in that case a larger buffer might be better. Still, if we are not cpu bound,
// a well saturated network might serve us better.
using (WriteOnlyBufferedStream bufferedStream = new WriteOnlyBufferedStream(this.conn.connector.Stream, 1024 * 1024 /*1500 - 20 - 20*/))
{
// The client connection preface starts with a sequence of 24 octets
bufferedStream.Write(MAGIC, 0, MAGIC.Length);
// This sequence MUST be followed by a SETTINGS frame (Section 6.5), which MAY be empty.
// The client sends the client connection preface immediately upon receipt of a
// 101 (Switching Protocols) response (indicating a successful upgrade)
// or as the first application data octets of a TLS connection
// Set streams' initial window size to its maximum.
this.settings.InitiatedMySettings[HTTP2Settings.INITIAL_WINDOW_SIZE] = HTTPManager.HTTP2Settings.InitialStreamWindowSize;
this.settings.InitiatedMySettings[HTTP2Settings.MAX_CONCURRENT_STREAMS] = HTTPManager.HTTP2Settings.MaxConcurrentStreams;
this.settings.SendChanges(this.outgoingFrames);
// The default window size for the whole connection is 65535 bytes,
// but we want to set it to the maximum possible value.
Int64 diff = HTTPManager.HTTP2Settings.InitialConnectionWindowSize - 65535;
if (diff > 0)
this.outgoingFrames.Add(HTTP2FrameHelper.CreateWindowUpdateFrame(0, (UInt32)diff));
this.pingFrequency = HTTPManager.HTTP2Settings.PingFrequency;
while (this.isRunning)
{
if (!atLeastOneStreamHasAFrameToSend)
{
// buffered stream will call flush automatically if its internal buffer is full.
// But we have to make it sure that we flush remaining data before we go to sleep.
bufferedStream.Flush();
// Wait until we have to send the next ping, OR a new frame is received on the read thread.
// Sent Now Sent+frequency
//-----|--------|----|------------
int wait = (int)((this.lastPingSent + this.pingFrequency) - DateTime.UtcNow).TotalMilliseconds;
wait = (int)Math.Min(wait, this.MaxGoAwayWaitTime.TotalMilliseconds);
if (wait >= 1)
{
if (HTTPManager.Logger.Level <= Logger.Loglevels.All)
HTTPManager.Logger.Information("HTTP2Handler", string.Format("Sleeping for {0:N0}ms", wait));
this.newFrameSignal.WaitOne(wait);
}
}
DateTime now = DateTime.UtcNow;
if (now - this.lastPingSent >= this.pingFrequency)
{
this.lastPingSent = now;
var frame = HTTP2FrameHelper.CreatePingFrame(HTTP2PingFlags.None);
BufferHelper.SetLong(frame.Payload, 0, now.Ticks);
this.outgoingFrames.Add(frame);
}
// Process received frames
HTTP2FrameHeaderAndPayload header;
while (this.newFrames.TryDequeue(out header))
{
if (header.StreamId > 0)
{
HTTP2Stream http2Stream = FindStreamById(header.StreamId);
// Add frame to the stream, so it can process it when its Process function is called
if (http2Stream != null)
{
http2Stream.AddFrame(header, this.outgoingFrames);
}
else
{
// Error? It's possible that we closed and removed the stream while the server was in the middle of sending frames
//HTTPManager.Logger.Warning("HTTP2Handler", string.Format("No stream found for id: {0}! Can't deliver frame: {1}", header.StreamId, header));
}
}
else
{
switch (header.Type)
{
case HTTP2FrameTypes.SETTINGS:
this.settings.Process(header, this.outgoingFrames);
break;
case HTTP2FrameTypes.PING:
var pingFrame = HTTP2FrameHelper.ReadPingFrame(header);
// if it wasn't an ack for our ping, we have to send one
if ((pingFrame.Flags & HTTP2PingFlags.ACK) == 0)
{
var frame = HTTP2FrameHelper.CreatePingFrame(HTTP2PingFlags.ACK);
Array.Copy(pingFrame.OpaqueData, 0, frame.Payload, 0, pingFrame.OpaqueDataLength);
this.outgoingFrames.Add(frame);
}
break;
case HTTP2FrameTypes.WINDOW_UPDATE:
var windowUpdateFrame = HTTP2FrameHelper.ReadWindowUpdateFrame(header);
this.remoteWindow += windowUpdateFrame.WindowSizeIncrement;
break;
case HTTP2FrameTypes.GOAWAY:
// parse the frame, so we can print out detailed information
HTTP2GoAwayFrame goAwayFrame = HTTP2FrameHelper.ReadGoAwayFrame(header);
HTTPManager.Logger.Warning("HTTP2Handler", "Received GOAWAY frame: " + goAwayFrame.ToString());
string msg = string.Format("Server closing the connection! Error code: {0} ({1})", goAwayFrame.Error, goAwayFrame.ErrorCode);
for (int i = 0; i < this.clientInitiatedStreams.Count; ++i)
this.clientInitiatedStreams[i].Abort(msg);
// set the running flag to false, so the thread can exit
this.isRunning = false;
this.conn.State = HTTPConnectionStates.Closed;
break;
case HTTP2FrameTypes.ALT_SVC:
//HTTP2AltSVCFrame altSvcFrame = HTTP2FrameHelper.ReadAltSvcFrame(header);
// Implement
//HTTPManager.EnqueuePluginEvent(new PluginEventInfo(PluginEvents.AltSvcHeader, new AltSvcEventInfo(altSvcFrame.Origin, ))
break;
}
}
}
UInt32 maxConcurrentStreams = Math.Min(HTTPManager.HTTP2Settings.MaxConcurrentStreams, this.settings.RemoteSettings[HTTP2Settings.MAX_CONCURRENT_STREAMS]);
// pre-test stream count to lock only when truly needed.
if (this.clientInitiatedStreams.Count < maxConcurrentStreams && this.isRunning)
{
// grab requests from queue
HTTPRequest request;
while (this.clientInitiatedStreams.Count < maxConcurrentStreams && this.requestQueue.TryDequeue(out request))
{
#if !BESTHTTP_DISABLE_CACHING
// If possible load the full response from cache.
if (Caching.HTTPCacheService.IsCachedEntityExpiresInTheFuture(request))
{
PlatformSupport.Threading.ThreadedRunner.RunShortLiving<HTTP2Handler, HTTPRequest>((handler, req) =>
{
if (ConnectionHelper.TryLoadAllFromCache("HTTP2Handler", req))
req.State = HTTPRequestStates.Finished;
else
{
// If for some reason it couldn't load we place back the request to the queue.
handler.requestQueue.Enqueue(req);
handler.newFrameSignal.Set();
}
}, this, request);
}
else
#endif
{
// create a new stream
var newStream = new HTTP2Stream(this.settings, this.HPACKEncoder);
// process the request
newStream.Assign(request);
this.clientInitiatedStreams.Add(newStream);
}
}
}
// send any settings changes
this.settings.SendChanges(this.outgoingFrames);
atLeastOneStreamHasAFrameToSend = false;
// process other streams
// Room for improvement Streams should be processed by their priority!
for (int i = 0; i < this.clientInitiatedStreams.Count; ++i)
{
var stream = this.clientInitiatedStreams[i];
stream.Process(this.outgoingFrames);
// remove closed, empty streams (not enough to check the closed flag, a closed stream still can contain frames to send)
if (stream.State == HTTP2StreamStates.Closed && !stream.HasFrameToSend)
{
this.clientInitiatedStreams.RemoveAt(i--);
stream.Removed();
}
atLeastOneStreamHasAFrameToSend |= stream.HasFrameToSend;
this.lastInteraction = DateTime.UtcNow;
}
// If we encounter a data frame that too large for the current remote window, we have to stop
// sending all data frames as we could send smaller data frames before the large ones.
// Room for improvement: An improvement would be here to stop data frame sending per-stream.
bool haltDataSending = false;
if (this.ShutdownType == ShutdownTypes.Running && now - this.lastInteraction >= HTTPManager.HTTP2Settings.MaxIdleTime)
{
this.lastInteraction = DateTime.UtcNow;
HTTPManager.Logger.Information("HTTP2Handler", "Reached idle time, sending GoAway frame!");
this.outgoingFrames.Add(HTTP2FrameHelper.CreateGoAwayFrame(0, HTTP2ErrorCodes.NO_ERROR));
this.goAwaySentAt = DateTime.UtcNow;
}
// https://httpwg.org/specs/rfc7540.html#GOAWAY
// Endpoints SHOULD always send a GOAWAY frame before closing a connection so that the remote peer can know whether a stream has been partially processed or not.
if (this.ShutdownType == ShutdownTypes.Gentle)
{
HTTPManager.Logger.Information("HTTP2Handler", "Connection abort requested, sending GoAway frame!");
this.outgoingFrames.Clear();
this.outgoingFrames.Add(HTTP2FrameHelper.CreateGoAwayFrame(0, HTTP2ErrorCodes.NO_ERROR));
this.goAwaySentAt = DateTime.UtcNow;
}
if (this.isRunning && now - goAwaySentAt >= this.MaxGoAwayWaitTime)
{
HTTPManager.Logger.Information("HTTP2Handler", "No GoAway frame received back. Really quitting now!");
this.isRunning = false;
conn.State = HTTPConnectionStates.Closed;
}
uint streamWindowUpdates = 0;
// Go through all the collected frames and send them.
for (int i = 0; i < this.outgoingFrames.Count; ++i)
{
var frame = this.outgoingFrames[i];
if (HTTPManager.Logger.Level <= Logger.Loglevels.All && frame.Type != HTTP2FrameTypes.DATA /*&& frame.Type != HTTP2FrameTypes.PING*/)
HTTPManager.Logger.Information("HTTP2Handler", "Sending frame: " + frame.ToString());
// post process frames
switch (frame.Type)
{
case HTTP2FrameTypes.DATA:
if (haltDataSending)
continue;
// if the tracked remoteWindow is smaller than the frame's payload, we stop sending
// data frames until we receive window-update frames
if (frame.PayloadLength > this.remoteWindow)
{
haltDataSending = true;
HTTPManager.Logger.Warning("HTTP2Handler", string.Format("Data sending halted for this round. Remote Window: {0:N0}, frame: {1}", this.remoteWindow, frame.ToString()));
continue;
}
break;
case HTTP2FrameTypes.WINDOW_UPDATE:
if (frame.StreamId > 0)
streamWindowUpdates += BufferHelper.ReadUInt31(frame.Payload, 0);
break;
}
this.outgoingFrames.RemoveAt(i--);
using (var buffer = HTTP2FrameHelper.HeaderAsBinary(frame))
bufferedStream.Write(buffer.Data, 0, buffer.Length);
if (frame.PayloadLength > 0)
{
bufferedStream.Write(frame.Payload, (int)frame.PayloadOffset, (int)frame.PayloadLength);
if (!frame.DontUseMemPool)
BufferPool.Release(frame.Payload);
}
if (frame.Type == HTTP2FrameTypes.DATA)
this.remoteWindow -= frame.PayloadLength;
}
if (streamWindowUpdates > 0)
{
var frame = HTTP2FrameHelper.CreateWindowUpdateFrame(0, streamWindowUpdates);
if (HTTPManager.Logger.Level <= Logger.Loglevels.All)
HTTPManager.Logger.Information("HTTP2Handler", "Sending frame: " + frame.ToString());
using (var buffer = HTTP2FrameHelper.HeaderAsBinary(frame))
bufferedStream.Write(buffer.Data, 0, buffer.Length);
bufferedStream.Write(frame.Payload, (int)frame.PayloadOffset, (int)frame.PayloadLength);
}
} // while (this.isRunning)
bufferedStream.Flush();
}
}
catch (Exception ex)
{
// Log out the exception if it's a non-expected one.
if (this.ShutdownType == ShutdownTypes.Running && this.goAwaySentAt == DateTime.MaxValue)
HTTPManager.Logger.Exception("HTTP2Handler", "Sender thread", ex);
}
finally
{
HTTPManager.Logger.Information("HTTP2Handler", "Sender thread closing - cleaning up remaining request...");
HTTPRequest request = null;
while (this.requestQueue.TryDequeue(out request))
{
HTTPManager.Logger.Information("HTTP2Handler", string.Format("Request '{0}' IsCancellationRequested: {1}", request.CurrentUri.ToString(), request.IsCancellationRequested.ToString()));
if (request.IsCancellationRequested)
{
request.Response = null;
request.State = HTTPRequestStates.Aborted;
}
else
RequestEventHelper.EnqueueRequestEvent(new RequestEventInfo(request, RequestEvents.Resend));
}
HTTPManager.Logger.Information("HTTP2Handler", "Sender thread closing");
}
if (this.conn.connector.Stream != null)
{
try
{
this.conn.connector.Stream.Dispose();
//this.conn.connector.Stream = null;
}
catch
{ }
}
if (Interlocked.Increment(ref this.threadExitCount) == 2 /*&& this.ShutdownType != ShutdownTypes.Immediate*/)
ConnectionEventHelper.EnqueueConnectionEvent(new ConnectionEventInfo(this.conn, HTTPConnectionStates.Closed));
}
private void ReadThread()
{
try
{
Thread.CurrentThread.Name = "HTTP2 Read";
HTTPManager.Logger.Information("HTTP2Handler", "Reader thread up and running!");
using (ReadOnlyBufferedStream bufferedStream = new ReadOnlyBufferedStream(this.conn.connector.Stream, 32 * 1024))
{
while (this.isRunning)
{
// TODO:
// 1. Set the local window to a reasonable size
// 2. stop reading when the local window is about to be 0.
// 3.
HTTP2FrameHeaderAndPayload header = HTTP2FrameHelper.ReadHeader(bufferedStream);
if (HTTPManager.Logger.Level <= Logger.Loglevels.Information && header.Type != HTTP2FrameTypes.DATA /*&& header.Type != HTTP2FrameTypes.PING*/)
HTTPManager.Logger.Information("HTTP2Handler", "New frame received: " + header.ToString());
// Add the new frame to the queue. Processing it on the write thread gives us the advantage that
// we don't have to deal with too much locking.
this.newFrames.Enqueue(header);
// ping write thread to process the new frame
this.newFrameSignal.Set();
switch (header.Type)
{
// Handle pongs on the read thread, so no additional latency is added to the rtt calculation.
case HTTP2FrameTypes.PING:
var pingFrame = HTTP2FrameHelper.ReadPingFrame(header);
if ((pingFrame.Flags & HTTP2PingFlags.ACK) != 0)
{
// it was an ack, payload must contain what we sent
var ticks = BufferHelper.ReadLong(pingFrame.OpaqueData, 0);
// the difference between the current time and the time when the ping message is sent
TimeSpan diff = TimeSpan.FromTicks(DateTime.UtcNow.Ticks - ticks);
// add it to the buffer
this.rtts.Add(diff.TotalMilliseconds);
// and calculate the new latency
this.Latency = CalculateLatency();
HTTPManager.Logger.Verbose("HTTP2Handler", string.Format("Latency: {0:F2}ms, RTT buffer: {1}", this.Latency, this.rtts.ToString()));
}
break;
case HTTP2FrameTypes.GOAWAY:
// Just exit from this thread. The processing thread will handle the frame too.
return;
}
}
}
}
catch //(Exception ex)
{
//HTTPManager.Logger.Exception("HTTP2Handler", "", ex);
this.isRunning = false;
this.newFrameSignal.Set();
}
finally
{
HTTPManager.Logger.Information("HTTP2Handler", "Reader thread closing");
}
if (Interlocked.Increment(ref this.threadExitCount) == 2 /*&& this.ShutdownType != ShutdownTypes.Immediate*/)
ConnectionEventHelper.EnqueueConnectionEvent(new ConnectionEventInfo(this.conn, HTTPConnectionStates.Closed));
}
private double CalculateLatency()
{
if (this.rtts.Count == 0)
return 0;
double sumLatency = 0;
for (int i = 0; i < this.rtts.Count; ++i)
sumLatency += this.rtts[i];
return sumLatency / this.rtts.Count;
}
HTTP2Stream FindStreamById(UInt32 streamId)
{
for (int i = 0; i < this.clientInitiatedStreams.Count; ++i)
{
var stream = this.clientInitiatedStreams[i];
if (stream.Id == streamId)
return stream;
}
return null;
}
public ShutdownTypes ShutdownType { get; private set; }
public void Shutdown(ShutdownTypes type)
{
this.ShutdownType = type;
switch(this.ShutdownType)
{
case ShutdownTypes.Gentle:
this.newFrameSignal.Set();
break;
case ShutdownTypes.Immediate:
this.conn.connector.Stream.Dispose();
break;
}
}
public void Dispose()
{
Dispose(true);
GC.SuppressFinalize(this);
}
private void Dispose(bool disposing)
{
if (this.newFrameSignal != null)
this.newFrameSignal.Close();
this.newFrameSignal = null;
}
~HTTP2Handler()
{
Dispose(false);
}
}
}
#endif
