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Fix WebSocket sendFrame delay by enabling TCP_NODELAY #5077

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Merged
aleks-f merged 5 commits into from
Dec 9, 2025
+20 −0
Merged

Fix WebSocket sendFrame delay by enabling TCP_NODELAY #5077

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56f28c5
Initial plan
Copilot Dec 8, 2025
47583fb
Fix WebSocket sendFrame delay by enabling TCP_NODELAY
Copilot Dec 8, 2025
8a3b177
Address code review feedback
Copilot Dec 8, 2025
ca9b050
Refine exception handling for TCP_NODELAY configuration
Copilot Dec 8, 2025
f187973
Consolidate exception handling for better maintainability
Copilot Dec 8, 2025
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4 changes: 4 additions & 0 deletions Net/include/Poco/Net/WebSocket.h
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Original file line number Diff line number Diff line change
Expand Up @@ -54,6 +54,10 @@ class Net_API WebSocket: public StreamSocket
/// mode, by calling setBlocking(false).
/// Please refer to the sendFrame() and receiveFrame() documentation
/// for non-blocking behavior.
///
/// TCP_NODELAY is automatically enabled on the underlying socket
/// to prevent delays from Nagle's algorithm when sending small
/// WebSocket frames.
{
public:
enum Mode
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16 changes: 16 additions & 0 deletions Net/src/WebSocketImpl.cpp
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Expand Up @@ -18,6 +18,7 @@
#include "Poco/Net/NetException.h"
#include "Poco/Net/WebSocket.h"
#include "Poco/Net/HTTPSession.h"
#include "Poco/Net/SocketAddress.h"
#include "Poco/Buffer.h"
#include "Poco/BinaryWriter.h"
#include "Poco/BinaryReader.h"
Expand All @@ -42,6 +43,21 @@ WebSocketImpl::WebSocketImpl(StreamSocketImpl* pStreamSocketImpl, HTTPSession& s
poco_check_ptr(pStreamSocketImpl);
_pStreamSocketImpl->duplicate();
session.drainBuffer(_buffer);
// Enable TCP_NODELAY to prevent delays caused by Nagle's algorithm
// for small WebSocket frames. Skip for Unix domain sockets.
try
{
if (_pStreamSocketImpl->address().family() != SocketAddress::UNIX_LOCAL)
_pStreamSocketImpl->setNoDelay(true);
}
catch (NetException&)
{
// Ignore - socket errors (e.g., not connected or doesn't support TCP options)
}
catch (Poco::Exception&)
{
// Ignore - other configuration errors (IOException, InvalidArgumentException, etc.)
}
}


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