mpd.py: changing exception raising to comply with the Python Style Guide

[python-musicpd.git] / mpd.py

diff --git a/mpd.py b/mpd.py
index be8b390482e2a18639f94298e025e2282f5400a8..8b70f4aa955ffcfcf2bda81f85c642879238e76b 100644 (file)
--- a/mpd.py
+++ b/mpd.py
@@ -26,6 +26,9 @@ NEXT = "list_OK"
 class MPDError(Exception):
     pass
 
+class ConnectionError(MPDError):
+    pass
+
 class ProtocolError(MPDError):
     pass
 
@@ -36,6 +39,13 @@ 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):
         self.iterate = False
@@ -116,13 +126,13 @@ class MPDClient(object):
         try:
             retval = self._commands[attr]
         except KeyError:
-            raise AttributeError, "'%s' object has no attribute '%s'" % \
-                                  (self.__class__.__name__, attr)
+            raise AttributeError("'%s' object has no attribute '%s'" %
+                                 (self.__class__.__name__, attr))
         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
+            raise CommandListError("%s not allowed in command list" % command)
         self._writecommand(command, args)
         if self._commandlist is None:
             if callable(retval):
@@ -131,8 +141,8 @@ class MPDClient(object):
         self._commandlist.append(retval)
 
     def _writeline(self, line):
-        self._sockfile.write("%s\n" % line)
-        self._sockfile.flush()
+        self._wfile.write("%s\n" % line)
+        self._wfile.flush()
 
     def _writecommand(self, command, args=[]):
         parts = [command]
@@ -141,15 +151,18 @@ class MPDClient(object):
         self._writeline(" ".join(parts))
 
     def _readline(self):
-        line = self._sockfile.readline().rstrip("\n")
+        line = self._rfile.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
+            raise CommandError(error)
         if self._commandlist is not None:
             if line == NEXT:
                 return
             if line == SUCCESS:
-                raise ProtocolError, "Got unexpected '%s'" % SUCCESS
+                raise ProtocolError("Got unexpected '%s'" % SUCCESS)
         elif line == SUCCESS:
             return
         return line
@@ -160,7 +173,7 @@ class MPDClient(object):
             return
         item = line.split(separator, 1)
         if len(item) < 2:
-            raise ProtocolError, "Could not parse item: '%s'" % line
+            raise ProtocolError("Could not parse item: '%s'" % line)
         return item
 
     def _readitems(self, separator=": "):
@@ -175,8 +188,8 @@ class MPDClient(object):
         for key, value in self._readitems():
             if key != seen:
                 if seen is not None:
-                    raise ProtocolError, "Expected key '%s', got '%s'" % \
-                                         (seen, key)
+                    raise ProtocolError("Expected key '%s', got '%s'" %
+                                        (seen, key))
                 seen = key
             yield value
         raise StopIteration
@@ -220,7 +233,7 @@ class MPDClient(object):
     def _getnone(self):
         line = self._readline()
         if line is not None:
-            raise ProtocolError, "Got unexpected return value: '%s'" % line
+            raise ProtocolError("Got unexpected return value: '%s'" % line)
 
     def _getitem(self):
         items = list(self._readitems())
@@ -259,36 +272,63 @@ class MPDClient(object):
         return self._wrapiterator(self._readcommandlist())
 
     def _hello(self):
-        line = self._sockfile.readline().rstrip("\n")
+        line = self._rfile.readline()
+        if not line.endswith("\n"):
+            raise ConnectionError("Connection lost while reading MPD hello")
+        line = line.rstrip("\n")
         if not line.startswith(HELLO_PREFIX):
-            raise ProtocolError, "Got invalid MPD hello: '%s'" % line
+            raise ProtocolError("Got invalid MPD hello: '%s'" % line)
         self.mpd_version = line[len(HELLO_PREFIX):].strip()
 
     def _reset(self):
         self.mpd_version = None
         self._commandlist = None
-        self._sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
-        self._sockfile = self._sock.makefile("rb+")
+        self._sock = None
+        self._rfile = _NotConnected()
+        self._wfile = _NotConnected()
 
     def connect(self, host, port):
-        self.disconnect()
-        self._sock.connect((host, port))
-        self._hello()
+        if self._sock:
+            raise ConnectionError("Already connected")
+        msg = "getaddrinfo returns an empty list"
+        for res in socket.getaddrinfo(host, port, socket.AF_UNSPEC,
+                                      socket.SOCK_STREAM, socket.IPPROTO_TCP,
+                                      socket.AI_ADDRCONFIG):
+            af, socktype, proto, canonname, sa = res
+            try:
+                self._sock = socket.socket(af, socktype, proto)
+                self._sock.connect(sa)
+            except socket.error, msg:
+                if self._sock:
+                    self._sock.close()
+                self._sock = None
+                continue
+            break
+        if not self._sock:
+            raise socket.error(msg)
+        self._rfile = self._sock.makefile("rb")
+        self._wfile = self._sock.makefile("wb")
+        try:
+            self._hello()
+        except (socket.error, MPDError):
+            self.disconnect()
+            raise
 
     def disconnect(self):
-        self._sockfile.close()
+        self._rfile.close()
+        self._wfile.close()
         self._sock.close()
         self._reset()
 
     def command_list_ok_begin(self):
         if self._commandlist is not None:
-            raise CommandListError, "Already in command list"
+            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"
+            raise CommandListError("Not in command list")
         self._writecommand("command_list_end")
         return self._getcommandlist()