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livetrax/libs/surfaces/websockets/server.cc
2020-04-22 21:59:34 +02:00

565 lines
14 KiB
C++

/*
* Copyright (C) 2020 Luciano Iam <lucianito@gmail.com>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program 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 General Public License for more details.
*
* You should have received a copy of the/GNU General Public License along
* with this program; if not, write to the Free Software Foundation, Inc.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*/
#ifndef NDEBUG
#include <iostream>
#endif
#include "dispatcher.h"
#include "server.h"
/* backport from libwebsockets 3.0,
* allow to compile on GNU/Linux with libwebsockets 2.x
*/
#ifndef PLATFORM_WINDOWS
#ifndef LWS_POLLHUP
#define LWS_POLLHUP (POLLHUP | POLLERR)
#endif
#ifndef LWS_POLLIN
#define LWS_POLLIN (POLLIN)
#endif
#ifndef LWS_POLLOUT
#define LWS_POLLOUT (POLLOUT)
#endif
#endif
#define MAX_INDEX_SIZE 65536
using namespace Glib;
WebsocketsServer::WebsocketsServer (ArdourSurface::ArdourWebsockets& surface)
: SurfaceComponent (surface)
, _lws_context (0)
{
/* keep references to all config for libwebsockets 2 */
lws_protocols proto;
memset (&proto, 0, sizeof (lws_protocols));
proto.name = "lws-ardour";
proto.callback = WebsocketsServer::lws_callback;
proto.rx_buffer_size = 0;
proto.id = 0;
proto.user = 0;
#if LWS_LIBRARY_VERSION_MAJOR >= 3
proto.tx_packet_size = 0;
#endif
_lws_proto[0] = proto;
memset (&_lws_proto[1], 0, sizeof (lws_protocols));
/* '/' is served by a static index.html file in the surface data directory
* inside it there is a 'builtin' subdirectory that contains all built-in
* surfaces so there is no need to create a dedicated mount point for them
* list of surfaces is available as a dynamically generated json file
*/
memset (&_lws_mnt_root, 0, sizeof (lws_http_mount));
_lws_mnt_root.mountpoint = "/";
_lws_mnt_root.mountpoint_len = strlen (_lws_mnt_root.mountpoint);
_lws_mnt_root.origin = _resources.index_dir ().c_str ();
_lws_mnt_root.origin_protocol = LWSMPRO_FILE;
_lws_mnt_root.def = "index.html";
_lws_mnt_root.cache_max_age = 3600;
_lws_mnt_root.cache_reusable = 1;
_lws_mnt_root.cache_revalidate = 1;
/* user defined surfaces in the user config directory */
memcpy (&_lws_mnt_user, &_lws_mnt_root, sizeof (lws_http_mount));
_lws_mnt_user.mountpoint = "/user";
_lws_mnt_user.mountpoint_len = strlen (_lws_mnt_user.mountpoint);
_lws_mnt_user.origin = _resources.user_dir ().c_str ();
_lws_mnt_root.mount_next = &_lws_mnt_user;
memset (&_lws_info, 0, sizeof (lws_context_creation_info));
_lws_info.port = WEBSOCKET_LISTEN_PORT;
_lws_info.protocols = _lws_proto;
_lws_info.mounts = &_lws_mnt_root;
_lws_info.uid = -1;
_lws_info.gid = -1;
_lws_info.user = this;
#if LWS_LIBRARY_VERSION_MAJOR < 3
/* older libwebsockets does not define mime type for svg files */
memset (&_lws_vhost_opt, 0, sizeof (lws_protocol_vhost_options));
_lws_vhost_opt.name = ".svg";
_lws_vhost_opt.value = "image/svg+xml";
_lws_mnt_root.extra_mimetypes = &_lws_vhost_opt;
_lws_mnt_user.extra_mimetypes = &_lws_vhost_opt;
#endif
}
int
WebsocketsServer::start ()
{
_lws_context = lws_create_context (&_lws_info);
if (!_lws_context) {
PBD::error << "ArdourWebsockets: could not create libwebsockets context" << endmsg;
return -1;
}
/* add_poll_fd() should have been called once during lws_create_context()
* if _fd_ctx is empty then LWS_CALLBACK_ADD_POLL_FD was not called
* this means libwesockets was not compiled with LWS_WITH_EXTERNAL_POLL
* - macos homebrew libwebsockets: disabled (3.2.2 as of Feb 2020)
* - linux ubuntu libwebsockets-dev: enabled (2.0.3 as of Feb 2020) but
* #if defined(LWS_WITH_EXTERNAL_POLL) check is not reliable -- constant
* missing from /usr/include/lws_config.h
*/
if (_fd_ctx.empty ()) {
PBD::error << "ArdourWebsockets: check your libwebsockets was compiled"
" with LWS_WITH_EXTERNAL_POLL enabled"
<< endmsg;
return -1;
}
return 0;
}
int
WebsocketsServer::stop ()
{
for (LwsPollFdGlibSourceMap::iterator it = _fd_ctx.begin (); it != _fd_ctx.end (); ++it) {
it->second.rg_iosrc->destroy ();
if (it->second.wg_iosrc) {
it->second.wg_iosrc->destroy ();
}
}
_fd_ctx.clear ();
if (_lws_context) {
lws_context_destroy (_lws_context);
_lws_context = 0;
}
return 0;
}
void
WebsocketsServer::update_client (Client wsi, const NodeState& state, bool force)
{
ClientContextMap::iterator it = _client_ctx.find (wsi);
if (it == _client_ctx.end ()) {
return;
}
if (force || !it->second.has_state (state)) {
/* write to client only if state was updated */
it->second.update_state (state);
it->second.output_buf ().push_back (NodeStateMessage (state));
lws_callback_on_writable (wsi);
}
}
void
WebsocketsServer::update_all_clients (const NodeState& state, bool force)
{
for (ClientContextMap::iterator it = _client_ctx.begin (); it != _client_ctx.end (); ++it) {
update_client (it->second.wsi (), state, force);
}
}
int
WebsocketsServer::add_poll_fd (struct lws_pollargs* pa)
{
/* fd can be SOCKET or int depending platform */
lws_sockfd_type fd = pa->fd;
#ifdef PLATFORM_WINDOWS
RefPtr<IOChannel> g_channel = IOChannel::create_from_win32_socket (fd);
#else
RefPtr<IOChannel> g_channel = IOChannel::create_from_fd (fd);
#endif
RefPtr<IOSource> rg_iosrc (IOSource::create (g_channel, events_to_ioc (pa->events)));
rg_iosrc->connect (sigc::bind (sigc::mem_fun (*this, &WebsocketsServer::io_handler), fd));
rg_iosrc->attach (main_loop ()->get_context ());
struct lws_pollfd lws_pfd;
lws_pfd.fd = pa->fd;
lws_pfd.events = pa->events;
lws_pfd.revents = 0;
LwsPollFdGlibSource ctx;
ctx.lws_pfd = lws_pfd;
ctx.g_channel = g_channel;
ctx.rg_iosrc = rg_iosrc;
ctx.wg_iosrc = Glib::RefPtr<Glib::IOSource> (0);
_fd_ctx[fd] = ctx;
return 0;
}
int
WebsocketsServer::mod_poll_fd (struct lws_pollargs* pa)
{
LwsPollFdGlibSourceMap::iterator it = _fd_ctx.find (pa->fd);
if (it == _fd_ctx.end ()) {
return 1;
}
it->second.lws_pfd.events = pa->events;
if (pa->events & LWS_POLLOUT) {
/* libwebsockets wants to write but cannot find a way to update
* an existing glib::iosource event flags using glibmm,
* create another iosource and set to IO_OUT, it will be destroyed
* after clearing POLLOUT (see 'else' body below)
*/
if (it->second.wg_iosrc) {
/* already polling for write */
return 0;
}
RefPtr<IOSource> wg_iosrc = it->second.g_channel->create_watch (Glib::IO_OUT);
wg_iosrc->connect (sigc::bind (sigc::mem_fun (*this, &WebsocketsServer::io_handler), pa->fd));
wg_iosrc->attach (main_loop ()->get_context ());
it->second.wg_iosrc = wg_iosrc;
} else {
if (it->second.wg_iosrc) {
it->second.wg_iosrc->destroy ();
it->second.wg_iosrc = Glib::RefPtr<Glib::IOSource> (0);
}
}
return 0;
}
int
WebsocketsServer::del_poll_fd (struct lws_pollargs* pa)
{
LwsPollFdGlibSourceMap::iterator it = _fd_ctx.find (pa->fd);
if (it == _fd_ctx.end ()) {
return 1;
}
it->second.rg_iosrc->destroy ();
if (it->second.wg_iosrc) {
it->second.wg_iosrc->destroy ();
}
_fd_ctx.erase (it);
return 0;
}
int
WebsocketsServer::add_client (Client wsi)
{
_client_ctx.emplace (wsi, ClientContext (wsi));
dispatcher ().update_all_nodes (wsi); // send all state
return 0;
}
int
WebsocketsServer::del_client (Client wsi)
{
ClientContextMap::iterator it = _client_ctx.find (wsi);
if (it != _client_ctx.end ()) {
_client_ctx.erase (it);
}
return 0;
}
int
WebsocketsServer::recv_client (Client wsi, void* buf, size_t len)
{
NodeStateMessage msg (buf, len);
if (!msg.is_valid ()) {
return 1;
}
#ifndef NDEBUG
std::cerr << "RX " << msg.state ().debug_str () << std::endl;
#endif
ClientContextMap::iterator it = _client_ctx.find (wsi);
if (it == _client_ctx.end ()) {
return 1;
}
/* avoid echo */
it->second.update_state (msg.state ());
dispatcher ().dispatch (wsi, msg);
return 0;
}
int
WebsocketsServer::write_client (Client wsi)
{
ClientContextMap::iterator it = _client_ctx.find (wsi);
if (it == _client_ctx.end ()) {
return 1;
}
ClientOutputBuffer& pending = it->second.output_buf ();
if (pending.empty ()) {
return 0;
}
/* one lws_write() call per LWS_CALLBACK_SERVER_WRITEABLE callback */
NodeStateMessage msg = pending.front ();
pending.pop_front ();
unsigned char out_buf[1024];
int len = msg.serialize (out_buf + LWS_PRE, 1024 - LWS_PRE);
if (len > 0) {
#ifndef NDEBUG
std::cerr << "TX " << msg.state ().debug_str () << std::endl;
#endif
if (lws_write (wsi, out_buf + LWS_PRE, len, LWS_WRITE_TEXT) != len) {
return 1;
}
} else {
PBD::error << "ArdourWebsockets: cannot serialize message" << endmsg;
}
if (!pending.empty ()) {
lws_callback_on_writable (wsi);
}
return 0;
}
int
WebsocketsServer::send_availsurf_hdr (Client wsi)
{
char url[1024];
if (lws_hdr_copy (wsi, url, 1024, WSI_TOKEN_GET_URI) < 0) {
return 1;
}
if (strcmp (url, "/surfaces.json") != 0) {
lws_return_http_status (wsi, 404, 0);
return 1;
}
unsigned char out_buf[1024],
*start = out_buf,
*p = start,
*end = &out_buf[sizeof(out_buf) - 1];
#if LWS_LIBRARY_VERSION_MAJOR >= 3
if ( lws_add_http_common_headers (wsi, HTTP_STATUS_OK, "application/json", LWS_ILLEGAL_HTTP_CONTENT_LEN, &p, end)
|| lws_add_http_header_by_token (wsi, WSI_TOKEN_HTTP_CACHE_CONTROL, reinterpret_cast<const unsigned char*> ("no-store"), 8, &p, end)
) {
return 1;
}
if (lws_finalize_write_http_header (wsi, start, &p, end) != 0) {
return 1;
}
#else
if ( lws_add_http_header_status (wsi, HTTP_STATUS_OK, &p, end)
|| lws_add_http_header_by_token (wsi, WSI_TOKEN_HTTP_CONTENT_TYPE, reinterpret_cast<const unsigned char*> ("application/json"), 16, &p, end)
|| lws_add_http_header_by_token (wsi, WSI_TOKEN_CONNECTION, reinterpret_cast<const unsigned char*> ("close"), 5, &p, end)
|| lws_add_http_header_by_token (wsi, WSI_TOKEN_HTTP_CACHE_CONTROL, reinterpret_cast<const unsigned char*> ("no-store"), 8, &p, end)
|| lws_finalize_http_header (wsi, &p, end)
) {
return 1;
}
int len = p - start;
if (lws_write (wsi, start, len, LWS_WRITE_HTTP_HEADERS) != len) {
return 1;
}
#endif
lws_callback_on_writable (wsi);
return 0;
}
int
WebsocketsServer::send_availsurf_body (Client wsi)
{
std::string index = _resources.scan ();
char body[MAX_INDEX_SIZE];
#if LWS_LIBRARY_VERSION_MAJOR >= 3
lws_strncpy (body, index.c_str (), sizeof(body));
#else
memset (body, 0, sizeof (body));
strncpy (body, index.c_str (), sizeof(body) - 1);
#endif
int len = strlen (body);
/* lws_write() expects a writable buffer */
if (lws_write (wsi, reinterpret_cast<unsigned char*> (body), len, LWS_WRITE_HTTP) != len) {
return 1;
}
/* lws_http_transaction_completed() returns 1 if the HTTP connection must close now
Returns 0 and resets connection to wait for new HTTP header / transaction if possible */
if (lws_http_transaction_completed (wsi) != 1) {
return -1;
}
return -1; // end connection
}
bool
WebsocketsServer::io_handler (Glib::IOCondition ioc, lws_sockfd_type fd)
{
/* IO_IN=1, IO_PRI=2, IO_OUT=4, IO_ERR=8, IO_HUP=16 */
LwsPollFdGlibSourceMap::iterator it = _fd_ctx.find (fd);
if (it == _fd_ctx.end ()) {
return false;
}
struct lws_pollfd* lws_pfd = &it->second.lws_pfd;
lws_pfd->revents = ioc_to_events (ioc);
lws_service_fd (_lws_context, lws_pfd);
return ioc & (Glib::IO_IN | Glib::IO_OUT);
}
IOCondition
WebsocketsServer::events_to_ioc (int events)
{
IOCondition ioc = Glib::IOCondition (0);
if (events & LWS_POLLIN) {
ioc |= Glib::IO_IN;
}
if (events & LWS_POLLOUT) {
ioc |= Glib::IO_OUT;
}
if (events & LWS_POLLHUP) {
ioc |= Glib::IO_HUP;
}
return ioc;
}
int
WebsocketsServer::ioc_to_events (IOCondition ioc)
{
int events = 0;
if (ioc & Glib::IO_IN) {
events |= LWS_POLLIN;
}
if (ioc & Glib::IO_OUT) {
events |= LWS_POLLOUT;
}
if (ioc & (Glib::IO_HUP | Glib::IO_ERR)) {
events |= LWS_POLLHUP;
}
return events;
}
int
WebsocketsServer::lws_callback (struct lws* wsi, enum lws_callback_reasons reason,
void* user, void* in, size_t len)
{
void* ctx_userdata = lws_context_user (lws_get_context (wsi));
WebsocketsServer* server = static_cast<WebsocketsServer*> (ctx_userdata);
int rc;
switch (reason) {
case LWS_CALLBACK_ADD_POLL_FD:
rc = server->add_poll_fd (static_cast<struct lws_pollargs*> (in));
break;
case LWS_CALLBACK_CHANGE_MODE_POLL_FD:
rc = server->mod_poll_fd (static_cast<struct lws_pollargs*> (in));
break;
case LWS_CALLBACK_DEL_POLL_FD:
rc = server->del_poll_fd (static_cast<struct lws_pollargs*> (in));
break;
case LWS_CALLBACK_ESTABLISHED:
rc = server->add_client (wsi);
break;
case LWS_CALLBACK_CLOSED:
rc = server->del_client (wsi);
break;
case LWS_CALLBACK_RECEIVE:
rc = server->recv_client (wsi, in, len);
break;
case LWS_CALLBACK_SERVER_WRITEABLE:
rc = server->write_client (wsi);
break;
/* will be called only if the requested url is not fulfilled
by the any of the mount configurations (root, user) */
case LWS_CALLBACK_HTTP:
rc = server->send_availsurf_hdr (wsi);
break;
case LWS_CALLBACK_HTTP_WRITEABLE:
rc = server->send_availsurf_body (wsi);
break;
case LWS_CALLBACK_CLOSED_HTTP:
case LWS_CALLBACK_FILTER_NETWORK_CONNECTION:
case LWS_CALLBACK_FILTER_PROTOCOL_CONNECTION:
case LWS_CALLBACK_SERVER_NEW_CLIENT_INSTANTIATED:
case LWS_CALLBACK_PROTOCOL_INIT:
case LWS_CALLBACK_PROTOCOL_DESTROY:
case LWS_CALLBACK_WSI_CREATE:
case LWS_CALLBACK_WSI_DESTROY:
case LWS_CALLBACK_LOCK_POLL:
case LWS_CALLBACK_UNLOCK_POLL:
case LWS_CALLBACK_WS_PEER_INITIATED_CLOSE:
case LWS_CALLBACK_FILTER_HTTP_CONNECTION:
#if LWS_LIBRARY_VERSION_MAJOR >= 3
case LWS_CALLBACK_HTTP_BIND_PROTOCOL:
case LWS_CALLBACK_ADD_HEADERS:
#if LWS_LIBRARY_VERSION_MINOR >= 1
case LWS_CALLBACK_HTTP_CONFIRM_UPGRADE:
#endif
#endif
/* do nothing but keep connection alive */
rc = 0;
break;
default:
#ifndef NDEBUG
/* see libwebsockets.h lws_callback_reasons */
std::cerr << "LWS: unhandled callback " << reason << std::endl;
#endif
rc = -1;
break;
}
return rc;
}