Reduce occurrences of bare exceptions

* replace bare exceptions with specific ones, if possible
* use "exc" instead of "e" as exception variable
  ("exc" is the most popular choice in the standard library)

config.py

@@ -107,7 +107,7 @@ DEFAULT_FROM_EMAIL = 'ivatar@mg.linux-kernel.at'
 
 try:
     from ivatar.settings import DATABASES
-except Exception:  # pragma: no cover
+except ImportError:  # pragma: no cover
     DATABASES = []  # pragma: no cover
 
 if 'default' not in DATABASES:

ivatar/ivataraccount/models.py

@@ -176,9 +176,9 @@ class Photo(BaseAccountModel):
         try:
             img = Image.open(BytesIO(self.data))
         # Testing? Ideas anyone?
-        except Exception as e:  # pylint: disable=invalid-name,broad-except
+        except Exception as exc:  # pylint: disable=broad-except
             # For debugging only
-            print('Exception caught: %s' % e)
+            print('Exception caught: %s' % exc)
             return False
         self.format = file_format(img.format)
         if not self.format:
@@ -537,8 +537,7 @@ class DjangoOpenIDStore(OpenIDStore):
             try:
                 # pylint: disable=no-member
                 expires = association.getExpiresIn()
-            # pylint: disable=invalid-name,broad-except,unused-variable
-            except Exception as e:
+            except AttributeError:
                 expires = association.expiresIn
             if expires == 0:
                 self.removeAssociation(server_url, assoc.handle)

ivatar/ivataraccount/read_libravatar_export.py

@@ -2,6 +2,7 @@
 Reading libravatar export
 '''
 
+import binascii
 from io import BytesIO
 import gzip
 import xml.etree.ElementTree
@@ -46,22 +47,23 @@ def read_gzdata(gzdata=None):
         if photo.tag == '{%s}photo' % SCHEMAROOT:
             try:
                 data = base64.decodebytes(bytes(photo.text, 'utf-8'))
-            except Exception as e:  # pylint: disable=broad-except,invalid-name
+            except binascii.Error as exc:
                 print('Cannot decode photo; Encoding: %s, Format: %s: %s' % (
-                    photo.attrib['encoding'], photo.attrib['format'], e))
+                    photo.attrib['encoding'], photo.attrib['format'], exc))
                 continue
             try:
                 Image.open(BytesIO(data))
+            except Exception as exc:  # pylint: disable=broad-except
+                print('Cannot decode photo; Encoding: %s, Format: %s: %s' % (
+                    photo.attrib['encoding'], photo.attrib['format'], exc))
+                continue
+            else:
                 # If it is a working image, we can use it
                 photo.text.replace('\n', '')
                 photos.append({
                     'data': photo.text,
                     'format': photo.attrib['format'],
                 })
-            except Exception as e:  # pylint: disable=broad-except,invalid-name
-                print('Cannot decode photo; Encoding: %s, Format: %s: %s' % (
-                    photo.attrib['encoding'], photo.attrib['format'], e))
-                continue
 
     return {
         'emails': emails,

ivatar/ivataraccount/views.py

@@ -4,9 +4,11 @@ View classes for ivatar/ivataraccount/
 from io import BytesIO
 from urllib.request import urlopen
 import base64
+import binascii
 
 from PIL import Image
 
+from django.db.models import ProtectedError
 from django.contrib.auth.decorators import login_required
 from django.contrib.auth.models import User
 from django.utils.decorators import method_decorator
@@ -298,7 +300,7 @@ class ImportPhotoView(SuccessMessageMixin, TemplateView):
         if 'email_id' in kwargs:
             try:
                 addr = ConfirmedEmail.objects.get(pk=kwargs['email_id']).email
-            except Exception:  # pylint: disable=broad-except
+            except ConfirmedEmail.ObjectDoesNotExist:
                 messages.error(
                     self.request,
                     _('Address does not exist'))
@@ -316,10 +318,12 @@ class ImportPhotoView(SuccessMessageMixin, TemplateView):
                 email=addr,
                 default=404,
             )
-            try:
-                if libravatar_service_url:
-                    # if it doesn't work, it will be caught by except
+            if libravatar_service_url:
+                try:
                     urlopen(libravatar_service_url)
+                except OSError as exc:
+                    print('Exception caught during photo import: {}'.format(exc))
+                else:
                     context['photos'].append({
                         'service_url': libravatar_service_url,
                         'thumbnail_url': libravatar_service_url + '?s=80',
@@ -328,9 +332,6 @@ class ImportPhotoView(SuccessMessageMixin, TemplateView):
                         'height': 80,
                         'service_name': 'Libravatar',
                     })
-            except Exception as e:  # pylint: disable=broad-except,invalid-name
-                print('Exception caught during photo import: %s' % e)
-                pass
 
         return context
 
@@ -423,7 +424,7 @@ class DeletePhotoView(SuccessMessageMixin, View):
             photo = self.model.objects.get(  # pylint: disable=no-member
                 pk=kwargs['pk'], user=request.user)
             photo.delete()
-        except Exception:  # pylint: disable=broad-except
+        except (self.model.DoesNotExist, ProtectedError):
             messages.error(
                 request,
                 _('No such image or no permission to delete it'))
@@ -558,12 +559,12 @@ class RedirectOpenIDView(View):
 
         try:
             auth_request = openid_consumer.begin(user_url)
-        except consumer.DiscoveryFailure as e:  # pylint: disable=invalid-name
-            messages.error(request, _('OpenID discovery failed: %s' % e))
+        except consumer.DiscoveryFailure as exc:
+            messages.error(request, _('OpenID discovery failed: %s' % exc))
             return HttpResponseRedirect(reverse_lazy('profile'))
-        except UnicodeDecodeError as e:  # pragma: no cover pylint: disable=invalid-name
+        except UnicodeDecodeError as exc:  # pragma: no cover
             msg = _('OpenID discovery failed (userid=%s) for %s: %s' %
-                    (request.user.id, user_url.encode('utf-8'), e))
+                    (request.user.id, user_url.encode('utf-8'), exc))
             print(msg)
             messages.error(request, msg)
 
@@ -684,14 +685,14 @@ class CropPhotoView(TemplateView):
         if 'email' in request.POST:
             try:
                 email = ConfirmedEmail.objects.get(email=request.POST['email'])
-            except Exception:  # pylint: disable=broad-except
+            except ConfirmedEmail.DoesNotExist:
                 pass  # Ignore automatic assignment
 
         if 'openid' in request.POST:
             try:
                 openid = ConfirmedOpenId.objects.get(  # pylint: disable=no-member
                     openid=request.POST['openid'])
-            except Exception:  # pylint: disable=broad-except
+            except ConfirmedOpenId.DoesNotExist:
                 pass  # Ignore automatic assignment
 
         return photo.perform_crop(request, dimensions, email, openid)
@@ -747,15 +748,16 @@ class UploadLibravatarExportView(SuccessMessageMixin, FormView):
                                         email,
                                         _('address added successfully,\
                                             confirmation mail sent')))
-                            except Exception as e:  # pylint: disable=broad-except,invalid-name
+                            except Exception as exc:  # pylint: disable=broad-except
                                 # DEBUG
-                                print('Exception during adding mail address (%s): %s' % (email, e))
+                                print('Exception during adding mail address (%s): %s'
+                                      % (email, exc))
 
                     if arg.startswith('photo'):
                         try:
                             data = base64.decodebytes(bytes(request.POST[arg], 'utf-8'))
-                        except Exception as e:  # pylint: disable=broad-except,invalid-name
-                            print('Cannot decode photo: %s' % e)
+                        except binascii.Error as exc:
+                            print('Cannot decode photo: %s' % exc)
                             continue
                         try:
                             pilobj = Image.open(BytesIO(data))
@@ -768,8 +770,8 @@ class UploadLibravatarExportView(SuccessMessageMixin, FormView):
                             photo.format = file_format(pilobj.format)
                             photo.data = out.read()
                             photo.save()
-                        except Exception as e:  # pylint: disable=broad-except,invalid-name
-                            print('Exception during save: %s' % e)
+                        except Exception as exc:  # pylint: disable=broad-except
+                            print('Exception during save: %s' % exc)
                             continue
 
                 return HttpResponseRedirect(reverse_lazy('profile'))
@@ -799,17 +801,18 @@ class ResendConfirmationMailView(View):
         try:
             email = self.model.objects.get(  # pylint: disable=no-member
                 user=request.user, id=kwargs['email_id'])
+        except self.model.DoesNotExist:  # pragma: no cover  # pylint: disable=no-member
+            messages.error(request, _('ID does not exist'))
+        else:
             try:
                 email.send_confirmation_mail(
                     url=request.build_absolute_uri('/')[:-1])
                 messages.success(
                     request, '%s: %s' %
                     (_('Confirmation mail sent to'), email.email))
-            except Exception as e:  # pylint: disable=broad-except,invalid-name
+            except Exception as exc:  # pylint: disable=broad-except
                 messages.error(
                     request, '%s %s: %s' %
                     (_('Unable to send confirmation email for'),
-                     email.email, e))
-        except self.model.DoesNotExist:  # pragma: no cover  # pylint: disable=no-member
-            messages.error(request, _('ID does not exist'))
+                     email.email, exc))
         return HttpResponseRedirect(reverse_lazy('profile'))