Re: [libmicrohttpd] [GSoC Update] Week 2

[Didik Setiawan]

On Sat, Jun 17, 2017 at 01:30:57PM +0300, Evgeny Grin wrote:
> 
> On 17.06.2017 11:36, Tim Rühsen wrote:
>
> > All you need is the socket descriptor. How to call getsockname() + 
> > getnameinfo() to retrieve the port number you see in libwget/net.c/
> > wget_tcp_get_local_port().
> > 
> > If MHD doesn't have such a function, either try to get the socket 
> > descriptor 
> > or extend MHD with a small function (similar code as in  
> > wget_tcp_get_local_port).
> 
> There are several ways to implement it.
> First one:
> Initialise socket externally and start listen() on it. You can use any
> bind and port detection function.
> Pass socket FD to MHD_start_daemon() by MHD_OPTION_LISTEN_SOCKET.
> 
> Second one:
> Use MHD_start_daemon() with "0" as port number then use
> MHD_get_daemon_info() with MHD_DAEMON_INFO_LISTEN_FD to get listen
> socket FD. Use any port detection.
> 
> Third one:
> Implemented two day ago, works with MHD_VERSION >= 0x00095501 and on
> platforms that support getsockname().
> Use MHD_start_daemon() with "0" as port number then use
> MHD_get_daemon_info() with MHD_DAEMON_INFO_BIND_PORT to get port number.

Thanks for the detailed explanations. That's what I'm looking for, to fill the
missing piece.
 
> You can combine second and third methods:

I use this combination.

> -----------------------------------------------
>   int port_num;
> 
>   if(0) {}
> #if MHD_VERSION >= 0x00095501
>   else if (MHD_NO !=
>      MHD_is_feature_supported (MHD_FEATURE_AUTODETECT_BIND_PORT))
>   {
>     const union MHD_DaemonInfo *dinfo;
>     dinfo = MHD_get_daemon_info (d, MHD_DAEMON_INFO_BIND_PORT);
>     if (NULL == dinfo || 0 == dinfo->port)
>     {
>       /* Insert code to handle error. */
>       return -1;
>     }
>     port_num = (int)dinfo->port;
>   }
> #endif /* MHD_VERSION >= 0x00095501 */
>   else
>   {
>     const union MHD_DaemonInfo *dinfo;
>     MHD_socket sock_fd;
>     dinfo = MHD_get_daemon_info (d, MHD_OPTION_LISTEN_SOCKET);

Don't you mean:

dinfo = MHD_get_daemon_info(d, MHD_DAEMON_INFO_LISTEN_FD);

Because when I tried using MHD version < 0.9.55 the result is not as
expected.

>     if (NULL == dinfo)
>     {
>       /* Insert code to handle error. */
>       return -1;
>     }
>     sock_fd = dinfo->listen_fd;
>     /* Insert code to use port detection on provided socket. */
>   }
> -----------------------------------------------
> 
> Note that socket type used by MHD functions is 'MHD_socket'.
> MHD_socket is 'int' on POSIX platforms (Linux, *BSD, Unix, Darwin) and
> 'SOCKET' on Windows platform (excluding Cygwin, where MHD_socket is 'int').
> 
> -- 
> Best Wishes,
> Evgeny Grin
> 

Regards,
Didik Setiawan