playlist: added plugin for last.fm radio

This plugin will replace the last.fm input plugin, once the playlist
API is integrated into MPD.

2 files changed, 325 insertions, 0 deletions

diff --git a/src/playlist/lastfm_playlist_plugin.c b/src/playlist/lastfm_playlist_plugin.c
new file mode 100644
index 00000000..d7de2537
--- /dev/null
+++ b/src/playlist/lastfm_playlist_plugin.c
@@ -0,0 +1,300 @@
+/*
+ * 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 "playlist/lastfm_playlist_plugin.h"
+#include "playlist_plugin.h"
+#include "playlist_list.h"
+#include "conf.h"
+#include "uri.h"
+#include "song.h"
+#include "input_stream.h"
+
+#include <glib.h>
+
+#include <assert.h>
+#include <string.h>
+
+struct lastfm_playlist {
+	struct playlist_provider base;
+
+	struct input_stream is;
+
+	struct playlist_provider *xspf;
+};
+
+static struct {
+	char *user;
+	char *md5;
+} lastfm_config;
+
+static bool
+lastfm_init(const struct config_param *param)
+{
+	const char *user = config_get_block_string(param, "user", NULL);
+	const char *passwd = config_get_block_string(param, "password", NULL);
+
+	if (user == NULL || passwd == NULL) {
+		g_debug("disabling the last.fm playlist plugin "
+			"because account is not configured");
+		return false;
+	}
+
+#if GLIB_CHECK_VERSION(2,16,0)
+	lastfm_config.user = g_uri_escape_string(user, NULL, false);
+#else
+	lastfm_config.user = g_strdup(user);
+#endif
+
+#if GLIB_CHECK_VERSION(2,16,0)
+	if (strlen(passwd) != 32)
+		lastfm_config.md5 = g_compute_checksum_for_string(G_CHECKSUM_MD5,
+								  passwd, strlen(passwd));
+	else
+#endif
+		lastfm_config.md5 = g_strdup(passwd);
+
+	return true;
+}
+
+static void
+lastfm_finish(void)
+{
+	g_free(lastfm_config.user);
+	g_free(lastfm_config.md5);
+}
+
+/**
+ * Simple data fetcher.
+ * @param url path or url of data to fetch.
+ * @return data fetched, or NULL on error. Must be freed with g_free.
+ */
+static char *
+lastfm_get(const char *url)
+{
+	struct input_stream input_stream;
+	bool success;
+	int ret;
+	char buffer[4096];
+	size_t length = 0, nbytes;
+
+	success = input_stream_open(&input_stream, url);
+	if (!success)
+		return NULL;
+
+	while (!input_stream.ready) {
+		ret = input_stream_buffer(&input_stream);
+		if (ret < 0) {
+			input_stream_close(&input_stream);
+			return NULL;
+		}
+	}
+
+	do {
+		nbytes = input_stream_read(&input_stream, buffer + length,
+					   sizeof(buffer) - length);
+		if (nbytes == 0) {
+			if (input_stream_eof(&input_stream))
+				break;
+
+			/* I/O error */
+			input_stream_close(&input_stream);
+			return NULL;
+		}
+
+		length += nbytes;
+	} while (length < sizeof(buffer));
+
+	input_stream_close(&input_stream);
+	return g_strndup(buffer, length);
+}
+
+/**
+ * Ini-style value fetcher.
+ * @param response data through which to search.
+ * @param name name of value to search for.
+ * @return value for param name in param reponse or NULL on error. Free with g_free.
+ */
+static char *
+lastfm_find(const char *response, const char *name)
+{
+	size_t name_length = strlen(name);
+
+	while (true) {
+		const char *eol = strchr(response, '\n');
+		if (eol == NULL)
+			return NULL;
+
+		if (strncmp(response, name, name_length) == 0 &&
+		    response[name_length] == '=') {
+			response += name_length + 1;
+			return g_strndup(response, eol - response);
+		}
+
+		response = eol + 1;
+	}
+}
+
+static struct playlist_provider *
+lastfm_open_uri(const char *uri)
+{
+	struct lastfm_playlist *playlist;
+	char *p, *q, *response, *session;
+	bool success;
+
+	/* handshake */
+
+	p = g_strconcat("http://ws.audioscrobbler.com/radio/handshake.php?"
+			"version=1.1.1&platform=linux&"
+			"username=", lastfm_config.user, "&"
+			"passwordmd5=", lastfm_config.md5, "&"
+			"debug=0&partner=", NULL);
+	response = lastfm_get(p);
+	g_free(p);
+	if (response == NULL)
+		return NULL;
+
+	/* extract session id from response */
+
+	session = lastfm_find(response, "session");
+	g_free(response);
+	if (session == NULL) {
+		g_warning("last.fm handshake failed");
+		return NULL;
+	}
+
+#if GLIB_CHECK_VERSION(2,16,0)
+	q = g_uri_escape_string(session, NULL, false);
+	g_free(session);
+	session = q;
+#endif
+
+	g_debug("session='%s'", session);
+
+	/* "adjust" last.fm radio */
+
+	if (strlen(uri) > 9) {
+		char *escaped_uri;
+
+#if GLIB_CHECK_VERSION(2,16,0)
+		escaped_uri = g_uri_escape_string(uri, NULL, false);
+#else
+		escaped_uri = g_strdup(uri);
+#endif
+
+		p = g_strconcat("http://ws.audioscrobbler.com/radio/adjust.php?"
+				"session=", session, "&url=", escaped_uri, "&debug=0",
+				NULL);
+		g_free(escaped_uri);
+
+		response = lastfm_get(p);
+		g_free(response);
+		g_free(p);
+
+		if (response == NULL) {
+			g_free(session);
+			return NULL;
+		}
+	}
+
+	/* create the playlist object */
+
+	playlist = g_new(struct lastfm_playlist, 1);
+	playlist_provider_init(&playlist->base, &lastfm_playlist_plugin);
+
+	/* open the last.fm playlist */
+
+	p = g_strconcat("http://ws.audioscrobbler.com/radio/xspf.php?"
+			"sk=", session, "&discovery=0&desktop=1.5.1.31879",
+			NULL);
+	g_free(session);
+
+	success = input_stream_open(&playlist->is, p);
+	g_free(p);
+
+	if (!success) {
+		g_warning("Failed to load XSPF playlist");
+		g_free(playlist);
+		return NULL;
+	}
+
+	while (!playlist->is.ready) {
+		int ret = input_stream_buffer(&playlist->is);
+		if (ret < 0) {
+			input_stream_close(&playlist->is);
+			g_free(playlist);
+			return NULL;
+		}
+
+		if (ret == 0)
+			/* nothing was buffered - wait */
+			g_usleep(10000);
+	}
+
+	/* last.fm does not send a MIME type, we have to fake it here
+	   :-( */
+	g_free(playlist->is.mime);
+	playlist->is.mime = g_strdup("application/xspf+xml");
+
+	/* parse the XSPF playlist */
+
+	playlist->xspf = playlist_list_open_stream(&playlist->is, NULL);
+	if (playlist->xspf == NULL) {
+		input_stream_close(&playlist->is);
+		g_free(playlist);
+		g_warning("Failed to parse XSPF playlist");
+		return NULL;
+	}
+
+	return &playlist->base;
+}
+
+static void
+lastfm_close(struct playlist_provider *_playlist)
+{
+	struct lastfm_playlist *playlist = (struct lastfm_playlist *)_playlist;
+
+	playlist_plugin_close(playlist->xspf);
+	input_stream_close(&playlist->is);
+	g_free(playlist);
+}
+
+static struct song *
+lastfm_read(struct playlist_provider *_playlist)
+{
+	struct lastfm_playlist *playlist = (struct lastfm_playlist *)_playlist;
+
+	return playlist_plugin_read(playlist->xspf);
+}
+
+static const char *const lastfm_schemes[] = {
+	"lastfm",
+	NULL
+};
+
+const struct playlist_plugin lastfm_playlist_plugin = {
+	.name = "lastfm",
+
+	.init = lastfm_init,
+	.finish = lastfm_finish,
+	.open_uri = lastfm_open_uri,
+	.close = lastfm_close,
+	.read = lastfm_read,
+
+	.schemes = lastfm_schemes,
+};
diff --git a/src/playlist/lastfm_playlist_plugin.h b/src/playlist/lastfm_playlist_plugin.h
new file mode 100644
index 00000000..871a4a04
--- /dev/null
+++ b/src/playlist/lastfm_playlist_plugin.h
@@ -0,0 +1,25 @@
+/*
+ * 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.
+ */
+
+#ifndef MPD_PLAYLIST_LASTFM_PLAYLIST_PLUGIN_H
+#define MPD_PLAYLIST_LASTFM_PLAYLIST_PLUGIN_H
+
+extern const struct playlist_plugin lastfm_playlist_plugin;
+
+#endif