Re: [libmicrohttpd] Problem destroying response objects

[Jon Nalley]

On Fri, Mar 13, 2009 at 2:54 PM, Christian Grothoff <address@hidden> wrote:
> The suggested way to terminate these types of connections where clients fail
> to read from the socket is to use a timeout (use
> MHD_OPTION_CONNECTION_TIMEOUT); that will close idle connections and should
> then also destroy the response objects.

The problem with using MHD_OPTION_CONNECTION_TIMEOUT (for me) is that
the client could potentially drop and re-connect many times before the
timeout is reached.  Since I am trying to implement "ajax long
polling" (see 
http://en.wikipedia.org/wiki/Comet_(programming)#Ajax_with_long_polling)
I would prefer that clients not timeout if they are still connected
(or at least have a fairly long timeout).

I have solved my problem with the following patch.  Admittedly, this
is fairly specific to my particular problem.  The patch is also Linux
specific due to the _GNU_SOURCE and using POLLRDHUP (available in
linux since 2.6.17).


diff -r 9f2a4ba2c19e src/daemon/connection.c
--- a/src/daemon/connection.c   Mon Mar 16 10:52:06 2009 -0500
+++ b/src/daemon/connection.c   Mon Mar 16 11:38:10 2009 -0500
@@ -30,6 +30,9 @@
 #include "memorypool.h"
 #include "response.h"
 #include "reason_phrase.h"
+
+#define _GNU_SOURCE
+#include <poll.h>

 /**
  * Message to transmit when http 1.1 request is received
@@ -1765,6 +1768,7 @@
   unsigned int timeout;
   const char *end;
   char *line;
+  struct pollfd fds;

   while (1)
     {
@@ -2100,6 +2104,17 @@
       connection_close_error (connection);
       return MHD_NO;
     }
+  if (connection->socket_fd != -1)
+    {
+      fds.fd = connection->socket_fd;
+      fds.events = POLLRDHUP;
+      poll (&fds, 1, 1);
+      if (fds.revents & POLLRDHUP)
+        {
+          connection_close_error (connection);
+          return MHD_NO;
+        }
+    }
   return MHD_YES;

 }