Robert Gronenberg wrote:

I am using libmicrohttpd in a multithreaded application in the
thread-per-connection mode. In order to maintain statistics and such on
the various clients, the application should be notified about
connections being started and stopped. Something like the
MHD_OPTION_NOTIFY_COMPLETED for requests, but then for connections. As
far as I could find libmicrohttpd does not (yet) provide that functionality.

Attached is a patch that does add this functionality by registering a
connection notification callback function: MHD_OPTION_NOTIFY_CONNECTION
(inspired by the MHD_OPTION_NOTIFY_COMPLETED option).

Could this be included in libmicrohttpd?

=>

The patch was only working for multithreaded apps, so I adjusted it
to cover other threading models, fixed a merge issue and added the
ability to associate a void* with the callbacks (and obtain it via
MHD connection info).  And I updated the manual & ChangeLog. Now
I think it can be included ;-).

1 files changed, 27 insertions, 0 deletions

diff --git a/doc/libmicrohttpd.texi b/doc/libmicrohttpd.texi
index 76dc918b..7e13a27a 100644
--- a/doc/libmicrohttpd.texi
+++ b/doc/libmicrohttpd.texi
@@ -631,6 +631,25 @@ pointer to a function of type @code{MHD_RequestCompletedCallback()}
 and second a pointer to a closure to pass to the request completed
 callback.  The second pointer maybe @code{NULL}.
 
+@item MHD_OPTION_NOTIFY_CONNECTION
+Register a function that should be called when the TCP connection to a
+client is opened or closed.  Note that
+@code{MHD_OPTION_NOTIFY_COMPLETED} and the @code{con_cls} argument to
+the @code{MHD_AccessHandlerCallback} are per HTTP request (and there
+can be multiple HTTP requests per TCP connection).  The registered
+callback is called twice per TCP connection, with
+@code{MHD_CONNECTION_NOTIFY_STARTED} and
+@code{MHD_CONNECTION_NOTIFY_CLOSED} respectively.  An additional
+argument can be used to store TCP connection specific information,
+which can be retrieved using @code{MHD_CONNECTION_INFO_SOCKET_CONTEXT}
+during the lifetime of the TCP connection.  The respective location is
+not the same as the HTTP-request-specific @code{con_cls} from the
+@code{MHD_AccessHandlerCallback}.
+
+This option should be followed by @strong{TWO} pointers.  First a
+pointer to a function of type @code{MHD_NotifyConnectionCallback()}
+and second a pointer to a closure to pass to the request completed
+callback.  The second pointer maybe @code{NULL}.
 
 @item MHD_OPTION_PER_IP_CONNECTION_LIMIT
 Limit on the number of (concurrent) connections made to the
@@ -2579,6 +2598,14 @@ automatically (if the platform supports it).  As the connection
 callbacks are invoked in between, those might be used to set different
 values for TCP-CORK and TCP-NODELAY in the meantime.
 
+@item MHD_CONNECTION_INFO_SOCKET_CONTEXT
+Returns the client-specific pointer to a @code{void *} that was
+(possibly) set during a @code{MHD_NotifyConnectionCallback} when the
+socket was first accepted.  Note that this is NOT the same as the
+@code{con_cls} argument of the @code{MHD_AccessHandlerCallback}.  The
+@code{con_cls} is fresh for each HTTP request, while the
+@code{socket_context} is fresh for each socket.
+
 @end table
 @end deftp