On Sat, 24 Dec 2022, Andrew Haines via fpc-pascal wrote:
Hi,
I am trying to test the websocket client in fcl-web by making a simple echo
client. I have been unable to make it work using fpc trunk on linux64. I also
crosscompiled to win64 and ran it on wine with identical results. The project
is attached here if anyone can give some hints.
I am testing it with a server I found here https://github.com/vi/wsmirror
(written in rust) but also I tried it with some public echo servers. There is
a html/javascript websocket example also for testing it which is working.
I have no real guesses as to the problem. I modified the server that the
client connects to enough to know when it receives messages and what kind.
The server never identifies a proper message after the connection handshake
is completed. It gets something but it doesn't identify it as a text message
or ping or close etc. The server is dropping the connection after a few
seconds with ss -t dport = 8080 giving this:
State Recv-Q Send-Q Local Address:Port
CLOSE-WAIT 5 0 127.0.0.1:47828
I believe those are several ping packets the server is sending that the
client doesn't read.
One thing the websocket is doing is disabling MSG_SIGNAL so that when the
pipe is broken it doesn't show an exception. However the component doesn't
check for this and doesn't send the disconnect event.
I have made my own websocket component in the past which is working but I
wanted to try the one included with fpc.
I'm really baffled, I spent a long time to try and find what is wrong, even
putting debug code in the underlying socket components. And verifying that
the websocket frames are correct.
An oddity I noted is that TInetSocket.CanRead seems to always return false if
it's used as a client. I may not have understood that fully.
The FPC websocket protocol has been tested on the
'unofficial' testsuite for websocket
https://github.com/crossbario/autobahn-testsuite
and it passes all tests, and I have used it in commercial programs.
so your story is quite surprising to me.
Does the sample chat client/program work for you ?
When I have a moment, I'll look at your test program.
Michael.
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