From: Alex Rousskov <rousskov@measurement-factory.com>
Date: Mon, 10 Aug 2020 18:46:02 +0000 (+0000)
Subject: Do not send keep-alive in 101 (Switching Protocols) responses (#709)
X-Git-Tag: 4.15-20210522-snapshot~72
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=18ce34b290020c79943bcdaba5debcce568e57f0;p=thirdparty%2Fsquid.git

Do not send keep-alive in 101 (Switching Protocols) responses (#709)

... because it breaks clients using websocket_client[1] library and is
redundant in our HTTP/1.1 control messages anyway.

I suspect that at least some buggy clients are confused by a multi-value
Connection field rather than the redundant keep-alive signal itself, but
let's try to follow RFC 7230 Upgrade example more closely this time and
send no keep-alive at all.

[1] https://pypi.org/project/websocket_client/
---

diff --git a/src/servers/Http1Server.cc b/src/servers/Http1Server.cc
index 8a9439bb65..c457ba245c 100644
--- a/src/servers/Http1Server.cc
+++ b/src/servers/Http1Server.cc
@@ -360,7 +360,8 @@ Http::One::Server::writeControlMsgAndCall(HttpReply *rep, AsyncCall::Pointer &ca
 
     if (switching && /* paranoid: */ upgradeHeader.size()) {
         rep->header.putStr(Http::HdrType::UPGRADE, upgradeHeader.termedBuf());
-        rep->header.putStr(Http::HdrType::CONNECTION, "upgrade, keep-alive");
+        rep->header.putStr(Http::HdrType::CONNECTION, "upgrade");
+        // keep-alive is redundant, breaks some 101 (Switching Protocols) recipients
     } else {
         rep->header.putStr(Http::HdrType::CONNECTION, "keep-alive");
     }