always close cloudstorage sessions

1. propagate proper pdf filesize handling to GDrive and MSDrive classes
2. use the session as a context handler to assure it closes even if an exception is unhandled.

Dropbox.py

@@ -57,8 +57,10 @@ class Dropbox (CloudStorage.CloudStorage):
             'Content-Type'    : 'application/octet-stream',
             'Dropbox-API-Arg' : json.dumps (parameters)
         }
-        with closing (session.post (self.upload_endpoint,
-                                    data = response.content,
+        data = response.content
+        with session as s:
+            with closing (s.post (self.upload_endpoint,
+                                        data = data,
                                         headers = headers)) as r:
                 if 'error_summary' in r.text:
                     CloudStorage.error_log (r.text)

GDrive.py

@@ -54,10 +54,11 @@ class GDrive (CloudStorage.CloudStorage):
         }
         headers = {
             'X-Upload-Content-Type': request.headers['Content-Type'],
-            'X-Upload-Content-Length': request.headers['Content-Length'],
+            'X-Upload-Content-Length': str(len(request.content)),
             'Content-Type': 'application/json; charset=UTF-8',
         }
-        with closing (session.post (self.upload_endpoint,
+        with session as s:
+            with closing (s.post (self.upload_endpoint,
                                         data = json.dumps (file_metadata),
                                         headers = headers)) as r2:
                 r2.raise_for_status ()
@@ -66,7 +67,7 @@ class GDrive (CloudStorage.CloudStorage):
             headers = {
                 'Content-Type': request.headers['Content-Type'],
             }
-        with closing (session.put (session_uri,
+            with closing (s.put (session_uri,
                                        data = request.iter_content (1024 * 1024),
                                        headers = headers)) as r3:
                 r3.raise_for_status ()

MSDrive.py

@@ -50,7 +50,7 @@ class MSDrive(CloudStorage.CloudStorage):
             'description': 'A Project Gutenberg Ebook',
             "@microsoft.graph.conflictBehavior": "rename", 
         }
-        filesize = int(response.headers['Content-Length'])
+        filesize = len(response.content)
         url = self.upload_endpoint.format(filename=filename)
         chunk_size = 327680 # weird onedrive thing related to FAT tables
         upload_data = session.post(url, json={'item': item_data}).json()
@@ -60,14 +60,14 @@ class MSDrive(CloudStorage.CloudStorage):
                 'Content-Length': str(end - start + 1),
                 'Content-Range': 'bytes {}-{}/{}'.format(start, end, filesize)
             }
-
+        with session as s:
             if 'uploadUrl' in upload_data:
                 session_uri = upload_data['uploadUrl']
                 start = 0
                 end = min(chunk_size - 1, filesize - 1)
 
                 for chunk in response.iter_content(chunk_size):
-                r = session.put(
+                    r = s.put(
                         session_uri,
                         data=chunk,
                         headers=headers(start, end, filesize),
@@ -77,4 +77,3 @@ class MSDrive(CloudStorage.CloudStorage):
                     r.raise_for_status()
             else:
                 CloudStorage.log('no uploadUrl in %s' % upload_data)
-        session.close()