playlist/rss: new playlist plugin for RSS feeds

src/playlist/rss_playlist_plugin.c

@@ -0,0 +1,321 @@
+/*
+ * Copyright (C) 2003-2010 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 "config.h"
+#include "playlist/rss_playlist_plugin.h"
+#include "playlist_plugin.h"
+#include "input_stream.h"
+#include "song.h"
+#include "tag.h"
+
+#include <glib.h>
+
+#include <assert.h>
+#include <string.h>
+
+#undef G_LOG_DOMAIN
+#define G_LOG_DOMAIN "rss"
+
+/**
+ * This is the state object for the GLib XML parser.
+ */
+struct rss_parser {
+	/**
+	 * The list of songs (in reverse order because that's faster
+	 * while adding).
+	 */
+	GSList *songs;
+
+	/**
+	 * The current position in the XML file.
+	 */
+	enum {
+		ROOT, ITEM,
+	} state;
+
+	/**
+	 * The current tag within the "entry" element.  This is only
+	 * valid if state==ITEM.  TAG_NUM_OF_ITEM_TYPES means there
+	 * is no (known) tag.
+	 */
+	enum tag_type tag;
+
+	/**
+	 * The current song.  It is allocated after the "location"
+	 * element.
+	 */
+	struct song *song;
+};
+
+static const gchar *
+get_attribute(const gchar **attribute_names, const gchar **attribute_values,
+	      const gchar *name)
+{
+	for (unsigned i = 0; attribute_names[i] != NULL; ++i)
+		if (g_ascii_strcasecmp(attribute_names[i], name) == 0)
+			return attribute_values[i];
+
+	return NULL;
+}
+
+static void
+rss_start_element(G_GNUC_UNUSED GMarkupParseContext *context,
+		  const gchar *element_name,
+		  const gchar **attribute_names,
+		  const gchar **attribute_values,
+		  gpointer user_data, G_GNUC_UNUSED GError **error)
+{
+	struct rss_parser *parser = user_data;
+
+	switch (parser->state) {
+	case ROOT:
+		if (g_ascii_strcasecmp(element_name, "item") == 0) {
+			parser->state = ITEM;
+			parser->song = song_remote_new("rss:");
+			parser->tag = TAG_NUM_OF_ITEM_TYPES;
+		}
+
+		break;
+
+	case ITEM:
+		if (g_ascii_strcasecmp(element_name, "enclosure") == 0) {
+			const gchar *href = get_attribute(attribute_names,
+							  attribute_values,
+							  "url");
+			if (href != NULL) {
+				/* create new song object, and copy
+				   the existing tag over; we cannot
+				   replace the existing song's URI,
+				   because that attribute is
+				   immutable */
+				struct song *song = song_remote_new(href);
+
+				if (parser->song != NULL) {
+					song->tag = parser->song->tag;
+					parser->song->tag = NULL;
+					song_free(parser->song);
+				}
+
+				parser->song = song;
+			}
+		} else if (g_ascii_strcasecmp(element_name, "title") == 0)
+			parser->tag = TAG_TITLE;
+		else if (g_ascii_strcasecmp(element_name, "itunes:author") == 0)
+			parser->tag = TAG_ARTIST;
+
+		break;
+	}
+}
+
+static void
+rss_end_element(G_GNUC_UNUSED GMarkupParseContext *context,
+		const gchar *element_name,
+		gpointer user_data, G_GNUC_UNUSED GError **error)
+{
+	struct rss_parser *parser = user_data;
+
+	switch (parser->state) {
+	case ROOT:
+		break;
+
+	case ITEM:
+		if (g_ascii_strcasecmp(element_name, "item") == 0) {
+			if (strcmp(parser->song->uri, "rss:") != 0)
+				parser->songs = g_slist_prepend(parser->songs,
+								parser->song);
+			else
+				song_free(parser->song);
+
+			parser->state = ROOT;
+		} else
+			parser->tag = TAG_NUM_OF_ITEM_TYPES;
+
+		break;
+	}
+}
+
+static void
+rss_text(G_GNUC_UNUSED GMarkupParseContext *context,
+	 const gchar *text, gsize text_len,
+	 gpointer user_data, G_GNUC_UNUSED GError **error)
+{
+	struct rss_parser *parser = user_data;
+
+	switch (parser->state) {
+	case ROOT:
+		break;
+
+	case ITEM:
+		if (parser->tag != TAG_NUM_OF_ITEM_TYPES) {
+			if (parser->song->tag == NULL)
+				parser->song->tag = tag_new();
+			tag_add_item_n(parser->song->tag, parser->tag,
+				       text, text_len);
+		}
+
+		break;
+	}
+}
+
+static const GMarkupParser rss_parser = {
+	.start_element = rss_start_element,
+	.end_element = rss_end_element,
+	.text = rss_text,
+};
+
+static void
+song_free_callback(gpointer data, G_GNUC_UNUSED gpointer user_data)
+{
+	struct song *song = data;
+
+	song_free(song);
+}
+
+static void
+rss_parser_destroy(gpointer data)
+{
+	struct rss_parser *parser = data;
+
+	if (parser->state >= ITEM)
+		song_free(parser->song);
+
+	g_slist_foreach(parser->songs, song_free_callback, NULL);
+	g_slist_free(parser->songs);
+}
+
+/*
+ * The playlist object
+ *
+ */
+
+struct rss_playlist {
+	struct playlist_provider base;
+
+	GSList *songs;
+};
+
+static struct playlist_provider *
+rss_open_stream(struct input_stream *is)
+{
+	struct rss_parser parser = {
+		.songs = NULL,
+		.state = ROOT,
+	};
+	struct rss_playlist *playlist;
+	GMarkupParseContext *context;
+	char buffer[1024];
+	size_t nbytes;
+	bool success;
+	GError *error = NULL;
+
+	/* parse the RSS XML file */
+
+	context = g_markup_parse_context_new(&rss_parser,
+					     G_MARKUP_TREAT_CDATA_AS_TEXT,
+					     &parser, rss_parser_destroy);
+
+	while (true) {
+		nbytes = input_stream_read(is, buffer, sizeof(buffer), &error);
+		if (nbytes == 0) {
+			if (error != NULL) {
+				g_markup_parse_context_free(context);
+				g_warning("%s", error->message);
+				g_error_free(error);
+				return NULL;
+			}
+
+			break;
+		}
+
+		success = g_markup_parse_context_parse(context, buffer, nbytes,
+						       &error);
+		if (!success) {
+			g_warning("XML parser failed: %s", error->message);
+			g_error_free(error);
+			g_markup_parse_context_free(context);
+			return NULL;
+		}
+	}
+
+	success = g_markup_parse_context_end_parse(context, &error);
+	if (!success) {
+		g_warning("XML parser failed: %s", error->message);
+		g_error_free(error);
+		g_markup_parse_context_free(context);
+		return NULL;
+	}
+
+	/* create a #rss_playlist object from the parsed song list */
+
+	playlist = g_new(struct rss_playlist, 1);
+	playlist_provider_init(&playlist->base, &rss_playlist_plugin);
+	playlist->songs = g_slist_reverse(parser.songs);
+	parser.songs = NULL;
+
+	g_markup_parse_context_free(context);
+
+	return &playlist->base;
+}
+
+static void
+rss_close(struct playlist_provider *_playlist)
+{
+	struct rss_playlist *playlist = (struct rss_playlist *)_playlist;
+
+	g_slist_foreach(playlist->songs, song_free_callback, NULL);
+	g_slist_free(playlist->songs);
+	g_free(playlist);
+}
+
+static struct song *
+rss_read(struct playlist_provider *_playlist)
+{
+	struct rss_playlist *playlist = (struct rss_playlist *)_playlist;
+	struct song *song;
+
+	if (playlist->songs == NULL)
+		return NULL;
+
+	song = playlist->songs->data;
+	playlist->songs = g_slist_remove(playlist->songs, song);
+
+	return song;
+}
+
+static const char *const rss_suffixes[] = {
+	"rss",
+	NULL
+};
+
+static const char *const rss_mime_types[] = {
+	"application/rss+xml",
+	"text/xml",
+	NULL
+};
+
+const struct playlist_plugin rss_playlist_plugin = {
+	.name = "rss",
+
+	.open_stream = rss_open_stream,
+	.close = rss_close,
+	.read = rss_read,
+
+	.suffixes = rss_suffixes,
+	.mime_types = rss_mime_types,
+};

src/playlist/rss_playlist_plugin.h

@@ -0,0 +1,25 @@
+/*
+ * Copyright (C) 2003-2010 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.
+ */
+
+#ifndef MPD_PLAYLIST_RSS_PLAYLIST_PLUGIN_H
+#define MPD_PLAYLIST_RSS_PLAYLIST_PLUGIN_H
+
+extern const struct playlist_plugin rss_playlist_plugin;
+
+#endif

src/playlist_list.c

@@ -26,6 +26,7 @@
 #include "playlist/lastfm_playlist_plugin.h"
 #include "playlist/pls_playlist_plugin.h"
 #include "playlist/asx_playlist_plugin.h"
+#include "playlist/rss_playlist_plugin.h"
 #include "playlist/cue_playlist_plugin.h"
 #include "playlist/flac_playlist_plugin.h"
 #include "input_stream.h"
@@ -45,6 +46,7 @@ static const struct playlist_plugin *const playlist_plugins[] = {
 	&xspf_playlist_plugin,
 	&pls_playlist_plugin,
 	&asx_playlist_plugin,
+	&rss_playlist_plugin,
 #ifdef ENABLE_LASTFM
 	&lastfm_playlist_plugin,
 #endif