Refactored Office 365 Plugin (#1225)

apprise/attachment/base.py

@@ -269,25 +269,26 @@ def exists(self, retrieve_if_missing=True):
         cache = self.template_args['cache']['default'] \
             if self.cache is None else self.cache
 
-        if self.download_path and os.path.isfile(self.download_path) \
-                and cache:
+        try:
+            if self.download_path and os.path.isfile(self.download_path) \
+                    and cache:
 
-            # We have enough reason to look further into our cached content
-            # and verify it has not expired.
-            if cache is True:
-                # return our fixed content as is; we will always cache it
-                return True
+                # We have enough reason to look further into our cached content
+                # and verify it has not expired.
+                if cache is True:
+                    # return our fixed content as is; we will always cache it
+                    return True
 
-            # Verify our cache time to determine whether we will get our
-            # content again.
-            try:
-                age_in_sec = time.time() - os.stat(self.download_path).st_mtime
+                # Verify our cache time to determine whether we will get our
+                # content again.
+                age_in_sec = \
+                    time.time() - os.stat(self.download_path).st_mtime
                 if age_in_sec <= cache:
                     return True
 
-            except (OSError, IOError):
-                # The file is not present
-                pass
+        except (OSError, IOError):
+            # The file is not present
+            pass
 
         return False if not retrieve_if_missing else self.download()
 
@@ -359,12 +360,27 @@ def download(self):
 
     def open(self, mode='rb'):
         """
-        return our file pointer and track it (we'll auto close later
+        return our file pointer and track it (we'll auto close later)
         """
         pointer = open(self.path, mode=mode)
         self.__pointers.add(pointer)
         return pointer
 
+    def chunk(self, size=5242880):
+        """
+        A Generator that yield chunks of a file with the specified size.
+
+        By default the chunk size is set to 5MB (5242880 bytes)
+        """
+
+        with self.open() as file:
+            while True:
+                chunk = file.read(size)
+                if not chunk:
+                    break
+
+                yield chunk
+
     def __enter__(self):
         """
         support with keyword
@@ -431,7 +447,15 @@ def __len__(self):
         Returns the filesize of the attachment.
 
         """
-        return os.path.getsize(self.path) if self.path else 0
+        if not self:
+            return 0
+
+        try:
+            return os.path.getsize(self.path) if self.path else 0
+
+        except OSError:
+            # OSError can occur if the file is inaccessible
+            return 0
 
     def __bool__(self):
         """

apprise/attachment/file.py

@@ -101,7 +101,11 @@ def download(self, **kwargs):
         # Ensure any existing content set has been invalidated
         self.invalidate()
 
-        if not os.path.isfile(self.dirty_path):
+        try:
+            if not os.path.isfile(self.dirty_path):
+                return False
+
+        except OSError:
             return False
 
         if self.max_file_size > 0 and \