fix up the migration for encrypted documents and a couple other associated issues.

src/documents/migrations/1003_mime_types.py

@@ -30,12 +30,14 @@ def add_mime_types(apps, schema_editor):
     documents = Document.objects.all()
 
     for d in documents:
-        if d.storage_type == STORAGE_TYPE_GPG:
-            f = GnuPG.decrypted(open(source_path(d), "rb"))
-        else:
         f = open(source_path(d), "rb")
+        if d.storage_type == STORAGE_TYPE_GPG:
 
-        d.mime_type = magic.from_buffer(f.read(1024), mime=True)
+            data = GnuPG.decrypted(f)
+        else:
+            data = f.read(1024)
+
+        d.mime_type = magic.from_buffer(data, mime=True)
         d.save()
 
         f.close()

src/documents/views.py

@@ -169,7 +169,12 @@ class DocumentViewSet(RetrieveModelMixin,
         parser_class = get_parser_class_for_mime_type(mime_type)
         if parser_class:
             parser = parser_class(logging_group=None)
+
+            try:
                 return parser.extract_metadata(file, mime_type)
+            except Exception as e:
+                # TODO: cover GPG errors, remove later.
+                return []
         else:
             return []
 
@@ -215,7 +220,12 @@ class DocumentViewSet(RetrieveModelMixin,
     @cache_control(public=False, max_age=315360000)
     def thumb(self, request, pk=None):
         try:
-            return HttpResponse(Document.objects.get(id=pk).thumbnail_file,
+            doc = Document.objects.get(id=pk)
+            if doc.storage_type == Document.STORAGE_TYPE_GPG:
+                handle = GnuPG.decrypted(doc.thumbnail_file)
+            else:
+                handle = doc.thumbnail_file
+            return HttpResponse(handle,
                                 content_type='image/png')
         except (FileNotFoundError, Document.DoesNotExist):
             raise Http404()