httpd: new output plugin to replace "shout"

Let's get rid of the "shout" plugin, and the awfully complicated
icecast daemon setup!  MPD can do better if it's doing the HTTP server
stuff on its own.  This new plugin has several advantages:

- easier to set up - only one daemon, no password settings, no mount
  settings
- MPD controls the encoder and thus already knows the packet
  boundaries - icecast has to parse them
- MPD doesn't bother to encode data while nobody is listening

This implementation is very experimental (no header parsing, ignores
request URI, no icy-metadata, ...).  It should be able to suport
several encoders in parallel in the future (with different bit rates,
different codec, ...), to make MPD the perfect streaming server.  Once
MPD gets multi-player support, we can even mount several different
radio stations on one server.

1 files changed, 393 insertions, 0 deletions

diff --git a/src/output/httpd_output_plugin.c b/src/output/httpd_output_plugin.c
new file mode 100644
index 00000000..61591af2
--- /dev/null
+++ b/src/output/httpd_output_plugin.c
@@ -0,0 +1,393 @@
+/*
+ * Copyright (C) 2003-2009 The Music Player Daemon Project
+ * http://www.musicpd.org
+ *
+ * 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.
+ */
+
+#include "httpd_internal.h"
+#include "httpd_client.h"
+#include "output_api.h"
+#include "encoder_plugin.h"
+#include "encoder_list.h"
+#include "socket_util.h"
+#include "page.h"
+
+#include <assert.h>
+
+#include <netinet/in.h>
+#include <netdb.h>
+#include <unistd.h>
+#include <errno.h>
+
+#undef G_LOG_DOMAIN
+#define G_LOG_DOMAIN "httpd_output"
+
+/**
+ * The quark used for GError.domain.
+ */
+static inline GQuark
+httpd_output_quark(void)
+{
+	return g_quark_from_static_string("httpd_output");
+}
+
+static void *
+httpd_output_init(G_GNUC_UNUSED const struct audio_format *audio_format,
+		  const struct config_param *param,
+		  GError **error)
+{
+	struct httpd_output *httpd = g_new(struct httpd_output, 1);
+	const char *encoder_name;
+	const struct encoder_plugin *encoder_plugin;
+	guint port;
+	struct sockaddr_in *sin;
+
+	/* read configuration */
+
+	port = config_get_block_unsigned(param, "port", 8000);
+
+	encoder_name = config_get_block_string(param, "encoder", "vorbis");
+	encoder_plugin = encoder_plugin_get(encoder_name);
+	if (encoder_plugin_get == NULL) {
+		g_set_error(error, httpd_output_quark(), 0,
+			    "No such encoder: %s", encoder_name);
+		return NULL;
+	}
+
+	if (strcmp(encoder_name, "vorbis") == 0)
+		httpd->content_type = "application/x-ogg";
+	else if (strcmp(encoder_name, "lame") == 0)
+		httpd->content_type = "audio/mpeg";
+	else
+		httpd->content_type = "application/octet-stream";
+
+	/* initialize listen address */
+
+	sin = (struct sockaddr_in *)&httpd->address;
+	memset(sin, 0, sizeof(sin));
+	sin->sin_port = htons(port);
+	sin->sin_family = AF_INET;
+	sin->sin_addr.s_addr = INADDR_ANY;
+	httpd->address_size = sizeof(*sin);
+
+	/* initialize encoder */
+
+	httpd->encoder = encoder_init(encoder_plugin, param, error);
+	if (httpd->encoder == NULL)
+		return NULL;
+
+	httpd->mutex = g_mutex_new();
+
+	return httpd;
+}
+
+static void
+httpd_output_finish(void *data)
+{
+	struct httpd_output *httpd = data;
+
+	encoder_finish(httpd->encoder);
+	g_mutex_free(httpd->mutex);
+	g_free(httpd);
+}
+
+/**
+ * Creates a new #httpd_client object and adds it into the
+ * httpd_output.clients linked list.
+ */
+static void
+httpd_client_add(struct httpd_output *httpd, int fd)
+{
+	struct httpd_client *client = httpd_client_new(httpd, fd);
+
+	httpd->clients = g_list_prepend(httpd->clients, client);
+}
+
+static gboolean
+httpd_listen_in_event(G_GNUC_UNUSED GIOChannel *source,
+		      G_GNUC_UNUSED GIOCondition condition,
+		      gpointer data)
+{
+	struct httpd_output *httpd = data;
+	int fd;
+	struct sockaddr_storage sa;
+	socklen_t sa_length = sizeof(sa);
+
+	g_mutex_lock(httpd->mutex);
+
+	/* the listener socket has become readable - a client has
+	   connected */
+
+	fd = accept(httpd->fd, (struct sockaddr*)&sa, &sa_length);
+	if (fd >= 0)
+		httpd_client_add(httpd, fd);
+	else if (fd < 0 && errno != EINTR)
+		g_warning("accept() failed: %s", g_strerror(errno));
+
+	g_mutex_unlock(httpd->mutex);
+
+	return true;
+}
+
+/**
+ * Reads data from the encoder (as much as available) and returns it
+ * as a new #page object.
+ */
+static struct page *
+httpd_output_read_page(struct httpd_output *httpd)
+{
+	size_t size = 0, nbytes;
+
+	do {
+		nbytes = encoder_read(httpd->encoder, httpd->buffer + size,
+				      sizeof(httpd->buffer) - size);
+		if (nbytes == 0)
+			break;
+
+		size += nbytes;
+	} while (size < sizeof(httpd->buffer));
+
+	if (size == 0)
+		return NULL;
+
+	return page_new_copy(httpd->buffer, size);
+}
+
+static bool
+httpd_output_encoder_open(struct httpd_output *httpd,
+			  struct audio_format *audio_format,
+			  GError **error)
+{
+	bool success;
+
+	success = encoder_open(httpd->encoder, audio_format, error);
+	if (!success)
+		return false;
+
+	/* we have to remember the encoder header, i.e. the first
+	   bytes of encoder output after opening it, because it has to
+	   be sent to every new client */
+	httpd->header = httpd_output_read_page(httpd);
+	return true;
+}
+
+static bool
+httpd_output_open(void *data, struct audio_format *audio_format,
+		  GError **error)
+{
+	struct httpd_output *httpd = data;
+	bool success;
+	GIOChannel *channel;
+
+	g_mutex_lock(httpd->mutex);
+
+	/* create and set up listener socket */
+
+	httpd->fd = socket_bind_listen(PF_INET, SOCK_STREAM, 0,
+				       (struct sockaddr *)&httpd->address,
+				       httpd->address_size,
+				       16, error);
+	if (httpd->fd < 0) {
+		g_mutex_unlock(httpd->mutex);
+		return false;
+	}
+
+	channel = g_io_channel_unix_new(httpd->fd);
+	httpd->source_id = g_io_add_watch(channel, G_IO_IN,
+					  httpd_listen_in_event, httpd);
+	g_io_channel_unref(channel);
+
+	/* open the encoder */
+
+	success = httpd_output_encoder_open(httpd, audio_format, error);
+	if (!success) {
+		g_source_remove(httpd->source_id);
+		close(httpd->fd);
+		g_mutex_unlock(httpd->mutex);
+		return false;
+	}
+
+	/* initialize other attributes */
+
+	httpd->clients = NULL;
+	httpd->timer = timer_new(audio_format);
+
+	g_mutex_unlock(httpd->mutex);
+	return true;
+}
+
+static void
+httpd_client_delete(gpointer data, G_GNUC_UNUSED gpointer user_data)
+{
+	struct httpd_client *client = data;
+
+	httpd_client_free(client);
+}
+
+static void httpd_output_close(void *data)
+{
+	struct httpd_output *httpd = data;
+
+	g_mutex_lock(httpd->mutex);
+
+	timer_free(httpd->timer);
+
+	g_list_foreach(httpd->clients, httpd_client_delete, NULL);
+	g_list_free(httpd->clients);
+
+	if (httpd->header != NULL)
+		page_unref(httpd->header);
+
+	encoder_close(httpd->encoder);
+
+	g_source_remove(httpd->source_id);
+	close(httpd->fd);
+
+	g_mutex_unlock(httpd->mutex);
+}
+
+void
+httpd_output_remove_client(struct httpd_output *httpd,
+			   struct httpd_client *client)
+{
+	assert(httpd != NULL);
+	assert(client != NULL);
+
+	httpd->clients = g_list_remove(httpd->clients, client);
+}
+
+void
+httpd_output_send_header(struct httpd_output *httpd,
+			 struct httpd_client *client)
+{
+	if (httpd->header != NULL)
+		httpd_client_send(client, httpd->header);
+}
+
+static void
+httpd_client_check_queue(gpointer data, G_GNUC_UNUSED gpointer user_data)
+{
+	struct httpd_client *client = data;
+
+	if (httpd_client_queue_size(client) > 256 * 1024) {
+		g_debug("client is too slow, flushing its queue");
+		httpd_client_cancel(client);
+	}
+}
+
+static void
+httpd_client_send_page(gpointer data, gpointer user_data)
+{
+	struct httpd_client *client = data;
+	struct page *page = user_data;
+
+	httpd_client_send(client, page);
+}
+
+static bool
+httpd_output_encode_and_play(struct httpd_output *httpd,
+			     const void *chunk, size_t size, GError **error)
+{
+	bool success;
+	struct page *page;
+
+	success = encoder_write(httpd->encoder, chunk, size, error);
+	if (!success)
+		return false;
+
+	g_mutex_lock(httpd->mutex);
+	g_list_foreach(httpd->clients, httpd_client_check_queue, page);
+	g_mutex_unlock(httpd->mutex);
+
+	while ((page = httpd_output_read_page(httpd)) != NULL) {
+		g_mutex_lock(httpd->mutex);
+
+		g_list_foreach(httpd->clients,
+			       httpd_client_send_page, page);
+
+		g_mutex_unlock(httpd->mutex);
+		page_unref(page);
+	}
+
+	return true;
+}
+
+static size_t
+httpd_output_play(void *data, const void *chunk, size_t size, GError **error)
+{
+	struct httpd_output *httpd = data;
+	bool has_clients;
+
+	g_mutex_lock(httpd->mutex);
+	has_clients = httpd->clients != NULL;
+	g_mutex_unlock(httpd->mutex);
+
+	if (has_clients) {
+		bool success;
+
+		success = httpd_output_encode_and_play(httpd, chunk, size,
+						       error);
+		if (!success)
+			return 0;
+	}
+
+	if (!httpd->timer->started)
+		timer_start(httpd->timer);
+	else
+		timer_sync(httpd->timer);
+	timer_add(httpd->timer, size);
+
+	return size;
+}
+
+static void
+httpd_output_tag(void *data, const struct tag *tag)
+{
+	struct httpd_output *httpd = data;
+
+	/* XXX add suport for icy-metadata */
+
+	encoder_tag(httpd->encoder, tag, NULL);
+}
+
+static void
+httpd_client_cancel_callback(gpointer data, G_GNUC_UNUSED gpointer user_data)
+{
+	struct httpd_client *client = data;
+
+	httpd_client_cancel(client);
+}
+
+static void
+httpd_output_cancel(void *data)
+{
+	struct httpd_output *httpd = data;
+
+	g_mutex_lock(httpd->mutex);
+	g_list_foreach(httpd->clients, httpd_client_cancel_callback, NULL);
+	g_mutex_unlock(httpd->mutex);
+}
+
+const struct audio_output_plugin httpd_output_plugin = {
+	.name = "httpd",
+	.init = httpd_output_init,
+	.finish = httpd_output_finish,
+	.open = httpd_output_open,
+	.close = httpd_output_close,
+	.send_tag = httpd_output_tag,
+	.play = httpd_output_play,
+	.cancel = httpd_output_cancel,
+};