mpd.py: raise ConnectionError when trying to use an unconnected socket

[python-musicpd.git] / mpd.py

diff --git a/mpd.py b/mpd.py
index 7e92cc084426290971b0b00d37ca543a35befe60..02d27880d35759de8ea4cc960055720804703d23 100644 (file)
--- a/mpd.py
+++ b/mpd.py
@@ -1,13 +1,18 @@
-#! /usr/bin/env python
-
-# TODO: return {} if no object read (?)
-# TODO: implement argument checking/parsing (?)
-# TODO: check for EOF when reading and benchmark it
-# TODO: command_list support
-# TODO: converter support
-# TODO: global for parsing MPD_HOST/MPD_PORT
-# TODO: global for parsing MPD error messages
-# TODO: IPv6 support (AF_INET6)
+# Python MPD client library
+# Copyright (C) 2008  J. Alexander Treuman <jat@spatialrift.net>
+#
+# 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 3 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, see <http://www.gnu.org/licenses/>.
 
 import socket
 
@@ -15,17 +20,31 @@ import socket
 HELLO_PREFIX = "OK MPD "
 ERROR_PREFIX = "ACK "
 SUCCESS = "OK"
+NEXT = "list_OK"
 
 
 class MPDError(Exception):
     pass
 
+class ConnectionError(MPDError):
+    pass
+
 class ProtocolError(MPDError):
     pass
 
 class CommandError(MPDError):
     pass
 
+class CommandListError(MPDError):
+    pass
+
+
+class _NotConnected(object):
+    def __getattr__(self, attr):
+        return self._dummy
+
+    def _dummy(*args):
+        raise ConnectionError, "Not connected"
 
 class MPDClient(object):
     def __init__(self):
@@ -112,27 +131,39 @@ class MPDClient(object):
         return lambda *args: self._docommand(attr, args, retval)
 
     def _docommand(self, command, args, retval):
+        if self._commandlist is not None and not callable(retval):
+            raise CommandListError, "%s not allowed in command list" % command
         self._writecommand(command, args)
-        if callable(retval):
-            return retval()
-        return retval
+        if self._commandlist is None:
+            if callable(retval):
+                return retval()
+            return retval
+        self._commandlist.append(retval)
 
     def _writeline(self, line):
         self._sockfile.write("%s\n" % line)
         self._sockfile.flush()
 
-    def _writecommand(self, command, args):
+    def _writecommand(self, command, args=[]):
         parts = [command]
         for arg in args:
             parts.append('"%s"' % escape(str(arg)))
         self._writeline(" ".join(parts))
 
     def _readline(self):
-        line = self._sockfile.readline().rstrip("\n")
+        line = self._sockfile.readline()
+        if not line.endswith("\n"):
+            raise ConnectionError, "Connection lost while reading line"
+        line = line.rstrip("\n")
         if line.startswith(ERROR_PREFIX):
             error = line[len(ERROR_PREFIX):].strip()
             raise CommandError, error
-        if line == SUCCESS:
+        if self._commandlist is not None:
+            if line == NEXT:
+                return
+            if line == SUCCESS:
+                raise ProtocolError, "Got unexpected '%s'" % SUCCESS
+        elif line == SUCCESS:
             return
         return line
 
@@ -187,6 +218,13 @@ class MPDClient(object):
             yield obj
         raise StopIteration
 
+    def _readcommandlist(self):
+        for retval in self._commandlist:
+            yield retval()
+        self._commandlist = None
+        self._getnone()
+        raise StopIteration
+
     def _wrapiterator(self, iterator):
         if not self.iterate:
             return list(iterator)
@@ -200,7 +238,7 @@ class MPDClient(object):
     def _getitem(self):
         items = list(self._readitems())
         if len(items) != 1:
-            raise ProtocolError, "Expected 1 item, got %i" % len(items)
+            return
         return items[0][1]
 
     def _getlist(self):
@@ -212,7 +250,7 @@ class MPDClient(object):
     def _getobject(self):
         objs = list(self._readobjects())
         if not objs:
-            return
+            return {}
         return objs[0]
 
     def _getobjects(self, delimiters):
@@ -230,20 +268,29 @@ class MPDClient(object):
     def _getchanges(self):
         return self._getobjects(["cpos"])
 
+    def _getcommandlist(self):
+        return self._wrapiterator(self._readcommandlist())
+
     def _hello(self):
-        line = self._sockfile.readline().rstrip("\n")
+        line = self._sockfile.readline()
+        if not line.endswith("\n"):
+            raise ConnectionError, "Connection lost while reading MPD hello"
         if not line.startswith(HELLO_PREFIX):
             raise ProtocolError, "Got invalid MPD hello: '%s'" % line
         self.mpd_version = line[len(HELLO_PREFIX):].strip()
 
     def _reset(self):
         self.mpd_version = None
-        self._sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
-        self._sockfile = self._sock.makefile("rb+")
+        self._commandlist = None
+        self._sock = None
+        self._sockfile = _NotConnected()
 
     def connect(self, host, port):
-        self.disconnect()
+        if self._sock:
+            self.disconnect()
+        self._sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
         self._sock.connect((host, port))
+        self._sockfile = self._sock.makefile("rb+")
         self._hello()
 
     def disconnect(self):
@@ -251,6 +298,18 @@ class MPDClient(object):
         self._sock.close()
         self._reset()
 
+    def command_list_ok_begin(self):
+        if self._commandlist is not None:
+            raise CommandListError, "Already in command list"
+        self._writecommand("command_list_ok_begin")
+        self._commandlist = []
+
+    def command_list_end(self):
+        if self._commandlist is None:
+            raise CommandListError, "Not in command list"
+        self._writecommand("command_list_end")
+        return self._getcommandlist()
+
 
 def escape(text):
     return text.replace("\\", "\\\\").replace('"', '\\"')