input_lastfm: new input plugin for last.fm radio

The lastfm input plugin enables MPD to play lastfm:// URLs.  This
plugin is not complete yet: it plays only the first song in the
last.fm playlist, and the playlist parser isn't even implemented
properly.

2 files changed, 252 insertions, 0 deletions

diff --git a/src/input/lastfm_input_plugin.c b/src/input/lastfm_input_plugin.c
new file mode 100644
index 000000000..2e592a9c8
--- /dev/null
+++ b/src/input/lastfm_input_plugin.c
@@ -0,0 +1,228 @@
+/* the Music Player Daemon (MPD)
+ * Copyright (C) 2008 Max Kellermann <max@duempel.org>
+ * This project's homepage is: 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., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ */
+
+#include "input/lastfm_input_plugin.h"
+#include "input/curl_input_plugin.h"
+#include "input_plugin.h"
+#include "conf.h"
+
+#include <string.h>
+
+#undef G_LOG_DOMAIN
+#define G_LOG_DOMAIN "input_lastfm"
+
+static const char *lastfm_user, *lastfm_password;
+
+static bool
+lastfm_input_init(const struct config_param *param)
+{
+	lastfm_user = config_get_block_string(param, "user", NULL);
+	lastfm_password = config_get_block_string(param, "password", NULL);
+
+	return lastfm_user != NULL && lastfm_password != NULL;
+}
+
+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);
+}
+
+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 bool
+lastfm_input_open(struct input_stream *is, const char *url)
+{
+	char *md5, *p, *q, *response, *session, *stream_url;
+	bool success;
+
+	if (strncmp(url, "lastfm://", 9) != 0)
+		return false;
+
+	/* handshake */
+
+#if GLIB_CHECK_VERSION(2,16,0)
+	q = g_uri_escape_string(lastfm_user, NULL, false);
+#else
+	q = g_strdup(lastfm_username);
+#endif
+
+#if GLIB_CHECK_VERSION(2,16,0)
+	if (strlen(lastfm_password) != 32)
+		md5 = g_compute_checksum_for_string(G_CHECKSUM_MD5,
+						    lastfm_password,
+						    strlen(lastfm_password));
+	else
+#endif
+		md5 = g_strdup(lastfm_password);
+
+	p = g_strconcat("http://ws.audioscrobbler.com/radio/handshake.php?"
+			"version=1.1.1&platform=linux&"
+			"username=", q, "&"
+			"passwordmd5=", md5, "&debug=0&partner=", NULL);
+	g_free(q);
+	g_free(md5);
+
+	response = lastfm_get(p);
+	g_free(p);
+	if (response == NULL)
+		return false;
+
+	/* extract session id from response */
+
+	session = lastfm_find(response, "session");
+	stream_url = lastfm_find(response, "stream_url");
+	g_free(response);
+	if (session == NULL || stream_url == NULL) {
+		g_free(session);
+		g_free(stream_url);
+		return false;
+	}
+
+#if GLIB_CHECK_VERSION(2,16,0)
+		q = g_uri_escape_string(session, NULL, false);
+		g_free(session);
+		session = q;
+#endif
+
+	/* "adjust" last.fm radio */
+
+	if (strlen(url) > 9) {
+		char *escaped_url;
+
+#if GLIB_CHECK_VERSION(2,16,0)
+		escaped_url = g_uri_escape_string(url, NULL, false);
+#else
+		escaped_url = g_strdup(url);
+#endif
+
+		p = g_strconcat("http://ws.audioscrobbler.com/radio/adjust.php?"
+				"session=", session, "&url=", escaped_url, "&debug=0",
+				NULL);
+		g_free(escaped_url);
+
+		response = lastfm_get(p);
+		g_free(response);
+		g_free(p);
+
+		if (response == NULL) {
+			g_free(session);
+			g_free(stream_url);
+			return false;
+		}
+	}
+
+	/* load 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);
+
+	response = lastfm_get(p);
+	g_free(p);
+
+	if (response == NULL) {
+		g_free(stream_url);
+		return false;
+	}
+
+	p = strstr(response, "<location>");
+	if (p == NULL) {
+		g_free(response);
+		g_free(stream_url);
+		return false;
+	}
+
+	p += 10;
+	q = strchr(p, '<');
+
+	if (q == NULL) {
+		g_free(response);
+		g_free(stream_url);
+		return false;
+	}
+
+	g_free(stream_url);
+	stream_url = g_strndup(p, q - p);
+	g_free(response);
+
+	/* now really open the last.fm radio stream */
+
+	success = input_stream_open(is, stream_url);
+	g_free(stream_url);
+	return success;
+}
+
+const struct input_plugin lastfm_input_plugin = {
+	.name = "lastfm",
+	.init = lastfm_input_init,
+	.open = lastfm_input_open,
+};
diff --git a/src/input/lastfm_input_plugin.h b/src/input/lastfm_input_plugin.h
new file mode 100644
index 000000000..8a2854214
--- /dev/null
+++ b/src/input/lastfm_input_plugin.h
@@ -0,0 +1,24 @@
+/*
+ * 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., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ */
+
+#ifndef LASTFM_INPUT_PLUGIN_H
+#define LASTFM_INPUT_PLUGIN_H
+
+extern const struct input_plugin lastfm_input_plugin;
+
+#endif