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/*
This file is part of libmicrohttpd
Copyright (C) 2016 Christian Grothoff (and other contributing authors)
This library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
This library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with this library; if not, write to the Free Software
Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
/**
* @file upgrade_example.c
* @brief example for how to use libmicrohttpd upgrade
* @author Christian Grothoff
*
* Telnet to the HTTP server, use this in the request:
* GET / http/1.1
* Connection: Upgrade
*
* After this, whatever you type will be echo'ed back to you.
*/
#include "platform.h"
#include <microhttpd.h>
#include <pthread.h>
#define PAGE \
"<html><head><title>libmicrohttpd demo</title></head><body>libmicrohttpd demo</body></html>"
/**
* Change socket to blocking.
*
* @param fd the socket to manipulate
*/
static void
make_blocking (MHD_socket fd)
{
#if defined(MHD_POSIX_SOCKETS)
int flags;
flags = fcntl (fd, F_GETFL);
if (-1 == flags)
abort ();
if ((flags & ~O_NONBLOCK) != flags)
if (-1 == fcntl (fd, F_SETFL, flags & ~O_NONBLOCK))
abort ();
#elif defined(MHD_WINSOCK_SOCKETS)
unsigned long flags = 0;
if (0 != ioctlsocket (fd, (int) FIONBIO, &flags))
abort ();
#endif /* MHD_WINSOCK_SOCKETS */
}
static void
send_all (MHD_socket sock,
const char *buf,
size_t len)
{
ssize_t ret;
size_t off;
make_blocking (sock);
for (off = 0; off < len; off += ret)
{
ret = send (sock,
&buf[off],
len - off,
0);
if (0 > ret)
{
if (EAGAIN == errno)
{
ret = 0;
continue;
}
break;
}
if (0 == ret)
break;
}
}
struct MyData
{
struct MHD_UpgradeResponseHandle *urh;
char *extra_in;
size_t extra_in_size;
MHD_socket sock;
};
/**
* Main function for the thread that runs the interaction with
* the upgraded socket. Writes what it reads.
*
* @param cls the `struct MyData`
*/
static void *
run_usock (void *cls)
{
struct MyData *md = cls;
struct MHD_UpgradeResponseHandle *urh = md->urh;
char buf[128];
ssize_t got;
make_blocking (md->sock);
/* start by sending extra data MHD may have already read, if any */
if (0 != md->extra_in_size)
{
send_all (md->sock,
md->extra_in,
md->extra_in_size);
free (md->extra_in);
}
/* now echo in a loop */
while (1)
{
got = recv (md->sock,
buf,
sizeof (buf),
0);
if (0 >= got)
break;
send_all (md->sock,
buf,
got);
}
free (md);
MHD_upgrade_action (urh,
MHD_UPGRADE_ACTION_CLOSE);
return NULL;
}
/**
* Function called after a protocol "upgrade" response was sent
* successfully and the socket should now be controlled by some
* protocol other than HTTP.
*
* Any data already received on the socket will be made available in
* @e extra_in. This can happen if the application sent extra data
* before MHD send the upgrade response. The application should
* treat data from @a extra_in as if it had read it from the socket.
*
* Note that the application must not close() @a sock directly,
* but instead use #MHD_upgrade_action() for special operations
* on @a sock.
*
* Data forwarding to "upgraded" @a sock will be started as soon
* as this function return.
*
* Except when in 'thread-per-connection' mode, implementations
* of this function should never block (as it will still be called
* from within the main event loop).
*
* @param cls closure, whatever was given to #MHD_create_response_for_upgrade().
* @param connection original HTTP connection handle,
* giving the function a last chance
* to inspect the original HTTP request
* @param req_cls last value left in `req_cls` of the `MHD_AccessHandlerCallback`
* @param extra_in if we happened to have read bytes after the
* HTTP header already (because the client sent
* more than the HTTP header of the request before
* we sent the upgrade response),
* these are the extra bytes already read from @a sock
* by MHD. The application should treat these as if
* it had read them from @a sock.
* @param extra_in_size number of bytes in @a extra_in
* @param sock socket to use for bi-directional communication
* with the client. For HTTPS, this may not be a socket
* that is directly connected to the client and thus certain
* operations (TCP-specific setsockopt(), getsockopt(), etc.)
* may not work as expected (as the socket could be from a
* socketpair() or a TCP-loopback). The application is expected
* to perform read()/recv() and write()/send() calls on the socket.
* The application may also call shutdown(), but must not call
* close() directly.
* @param urh argument for #MHD_upgrade_action()s on this @a connection.
* Applications must eventually use this callback to (indirectly)
* perform the close() action on the @a sock.
*/
static void
uh_cb (void *cls,
struct MHD_Connection *connection,
void *req_cls,
const char *extra_in,
size_t extra_in_size,
MHD_socket sock,
struct MHD_UpgradeResponseHandle *urh)
{
struct MyData *md;
pthread_t pt;
(void) cls; /* Unused. Silent compiler warning. */
(void) connection; /* Unused. Silent compiler warning. */
(void) req_cls; /* Unused. Silent compiler warning. */
md = malloc (sizeof (struct MyData));
if (NULL == md)
abort ();
memset (md, 0, sizeof (struct MyData));
if (0 != extra_in_size)
{
md->extra_in = malloc (extra_in_size);
if (NULL == md->extra_in)
abort ();
memcpy (md->extra_in,
extra_in,
extra_in_size);
}
md->extra_in_size = extra_in_size;
md->sock = sock;
md->urh = urh;
if (0 != pthread_create (&pt,
NULL,
&run_usock,
md))
abort ();
/* Note that by detaching like this we make it impossible to ensure
a clean shutdown, as the we stop the daemon even if a worker thread
is still running. Alas, this is a simple example... */
pthread_detach (pt);
/* This callback must return as soon as possible. */
/* Data forwarding to "upgraded" socket will be started
* after return from this callback. */
}
static enum MHD_Result
ahc_echo (void *cls,
struct MHD_Connection *connection,
const char *url,
const char *method,
const char *version,
const char *upload_data,
size_t *upload_data_size,
void **req_cls)
{
static int aptr;
struct MHD_Response *response;
enum MHD_Result ret;
(void) cls; /* Unused. Silent compiler warning. */
(void) url; /* Unused. Silent compiler warning. */
(void) version; /* Unused. Silent compiler warning. */
(void) upload_data; /* Unused. Silent compiler warning. */
(void) upload_data_size; /* Unused. Silent compiler warning. */
if (0 != strcmp (method, "GET"))
return MHD_NO; /* unexpected method */
if (&aptr != *req_cls)
{
/* do never respond on first call */
*req_cls = &aptr;
return MHD_YES;
}
*req_cls = NULL; /* reset when done */
response = MHD_create_response_for_upgrade (&uh_cb,
NULL);
MHD_add_response_header (response,
MHD_HTTP_HEADER_UPGRADE,
"Echo Server");
ret = MHD_queue_response (connection,
MHD_HTTP_SWITCHING_PROTOCOLS,
response);
MHD_destroy_response (response);
return ret;
}
int
main (int argc,
char *const *argv)
{
struct MHD_Daemon *d;
if (argc != 2)
{
printf ("%s PORT\n", argv[0]);
return 1;
}
d = MHD_start_daemon (MHD_ALLOW_UPGRADE | MHD_USE_AUTO
| MHD_USE_INTERNAL_POLLING_THREAD | MHD_USE_ERROR_LOG,
atoi (argv[1]),
NULL, NULL,
&ahc_echo, NULL,
MHD_OPTION_CONNECTION_TIMEOUT, (unsigned int) 120,
MHD_OPTION_END);
if (d == NULL)
return 1;
(void) getc (stdin);
MHD_stop_daemon (d);
return 0;
}
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