[usocket-devel] Fwd: Detecting whether the other end has closed my socket stream

Samuel, (forwarded to the mailing list also) Basically, as I understand the problem, is that lisp LISTEN does not notify end of file/connection and characters avaiable in the same manner READ-CHAR-NO-HANG (and the character stream system) does. LISTEN returns false on char not available and end-of-file. READ-CHAR-NO-HANG (as well as READLINE) uses conditions. So, my question is, is there any different way (using usockets) of identifying when a non-char connection is closed? Thanks! ---------- Forwarded message ---------- From: Roger Sen Montero <roger.sen@gmail.com> Date: Thu, Mar 21, 2013 at 8:07 PM Subject: Re: Detecting whether the other end has closed my socket stream To: Samuel Edwin Ward <seward@cytochro.me> Samuel, I have identified the issue to a call to a listen when waiting to read the socket so I can multiplex multiple socket reading. http://paste.lisp.org/display/136157 With the current code COLLECT-INPUT (listen stream) is not raising the end of file condition. (defun collect-input (socket buffer &optional (end-char 13)) (loop :with stream = (usocket:socket-stream socket) :with byte :while (listen stream) :doing (setf byte (read-byte stream)) (when (= byte end-char) (return t)) (vector-push-extend byte buffer))) Taking out the listen and changing it to :while t raises the condition correctly when the connection is closed from client side, but then I'm unable to multiplex. On Thu, Mar 21, 2013 at 1:00 AM, Roger Sen Montero <roger.sen@gmail.com>wrote:
Samuel,
Let me create a simple test case from the current code and I'll post it here.
El miércoles, 13 de marzo de 2013, Samuel Edwin Ward escribió:
Hi Roger/all,
I wasn't able to reproduce this with my setup; I seem to get the end of file condition either way.
I'm using usocket 0.6.0.1 on sbcl 1.0.54.0-185b926 on Mac OS 10.7.5.
Can you provide your versions and/or a runnable test case?
On Mar 13, 2013, at 12:24, Roger Sen Montero <roger.sen@gmail.com> wrote:
Hi all!!
The FAQ states:
Reading from a stream which has been closed at the remote end signals an END-OF-FILE condition, meaning that reading from the stream and detecting that condition is the way to do it.
But when a create a server with:
:element-type 'character
I'm able to get an "Unexpected end of file" condition on the server side when the client disconnect.
Unfortunately, when I create the server with:
:element-type 'unsigned-byte
I do not get the condition, so I'm unable to detect when a client has disconnected.
Also, is there any plan to support utf8 streams directly without creating unsigned-byte sockets and converting from/to string to string-utf-8-bytes?
thanks! -- Roger Sen Montero roger.sen@gmail.com
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