almost alpha version

python_apps/media-monitor2/media/monitor/events.py

@@ -1,40 +1,67 @@
+# -*- coding: utf-8 -*-
 import os
 import mutagen
 import abc
+from media.monitor.exceptions import BadSongFile
 
-# Note: this isn't really good design...
-# Anyone who expects a BaseEvent object should be able to handle any instances
-# of its subclasses by the substitution principle. CLearly not the case with
-# the DeleteFile subclass.
+class PathChannel(object):
+    """a dumb struct; python has no record types"""
+    def __init__(self, signal, path):
+        self.signal = signal
+        self.path = path
 
 # It would be good if we could parameterize this class by the attribute
 # that would contain the path to obtain the meta data. But it would be too much
 # work for little reward
 class HasMetaData(object):
+    # TODO : add documentation for HasMetaData
     __metaclass__ = abc.ABCMeta
-    def __init__(self, *args, **kwargs):
-        self.__metadata = None
-        self.__loaded = False
+    # doing weird bullshit here because python constructors only
+    # call the constructor of the leftmost superclass.
     @property
     def metadata(self):
-        if self.__loaded: return self.__metadata
+        # Normally this would go in init but we don't like
+        # relying on consumers of this behaviour to have to call
+        # the constructor
+        if not hasattr(self,"_loaded"): self._loaded = False
+        if self._loaded: return self._metadata
         else:
-            f  = mutagen.File(self.path, easy=True)
-            self.__metadata = f
-            self.__loaded = True
+            f = None
+            try: f  = mutagen.File(self.path, easy=True)
+            except Exception: raise BadSongFile(self.path)
+            # value returned by mutagen only acts like a dictionary.
+            # in fact it comes with a nice surprise for you if you try
+            # to add elements to it
+            self._metadata = {}
+            for k,v in f:
+                if isinstance(v, list):
+                    if len(v) == 1:
+                        self._metadata[k] = v[0]
+                    else:
+                        raise Exception("Weird mutagen %s:%s" % (k,str(v)))
+                else:
+                    self._metadata[k] = v
+            self._loaded = True
             return self.metadata
 
+
 class BaseEvent(object):
     __metaclass__ = abc.ABCMeta
     def __init__(self, raw_event):
-        self.__raw_event = raw_event
-        self.path = os.path.normpath(raw_event.pathname)
-        super(BaseEvent, self).__init__()
+        # TODO : clean up this idiotic hack
+        # we should use keyword constructors instead of this behaviour checking
+        # bs to initialize BaseEvent
+        if getattr(raw_event,"pathname"):
+            self.__raw_event = raw_event
+            self.path = os.path.normpath(raw_event.pathname)
+        else: self.path = raw_event
     def exists(self): return os.path.exists(self.path)
     def __str__(self):
         return "Event. Path: %s" % self.__raw_event.pathname
 
-class OrganizeFile(BaseEvent, HasMetaData): pass
-class NewFile(BaseEvent, HasMetaData): pass
-class DeleteFile(BaseEvent): pass
-
+class OrganizeFile(BaseEvent, HasMetaData):
+    def __init__(self, *args, **kwargs): super(OrganizeFile, self).__init__(*args, **kwargs)
+class NewFile(BaseEvent, HasMetaData):
+    def __init__(self, *args, **kwargs): super(NewFile, self).__init__(*args, **kwargs)
+class DeleteFile(BaseEvent):
+    def __init__(self, *args, **kwargs): super(DeleteFile, self).__init__(*args, **kwargs)