From ce5288068bc74dbb06a096f651c9fbb572af3ccc Mon Sep 17 00:00:00 2001
From: Ferry Boender <ferry.boender@gmail.com>
Date: Sat, 25 Jul 2015 22:28:25 +0200
Subject: [PATCH] If the user doesn't upload a file, and the field is not
 required, don't raise a ValidationError.

---
 src/formdefinition.py | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/src/formdefinition.py b/src/formdefinition.py
index 35be8de..03ec5d7 100644
--- a/src/formdefinition.py
+++ b/src/formdefinition.py
@@ -244,7 +244,11 @@ class FormDefinition(object):
         try:
             value = form_values[field_def['name']]
         except KeyError:
-            raise ValidationError("Invalid file upload")
+            # Field is missing. Check if it's required.
+            if 'required' in field_def and field_def['required'] == True:
+                raise ValidationError("Invalid file upload")
+            else:
+                return ''
 
         field_name = field_def['name']
         upload_fname = form_values[u'{0}__name'.format(field_name)]