Fixed #9418 -- When saving a model form, defer saving of file-type fields until…

Fixed #9418 -- When saving a model form, defer saving of file-type fields until after other fields, so that callable upload_to methods can use data from the other fields.  Thanks to Bernd Schlapsi for the report and initial patch.


git-svn-id: http://code.djangoproject.com/svn/django/trunk@9334 bcc190cf-cafb-0310-a4f2-bffc1f526a37

AUTHORS

@@ -344,6 +344,7 @@ answer newbie questions, and generally made Django that much better:
     Ivan Sagalaev (Maniac) <http://www.softwaremaniacs.org/>
     Vinay Sajip <vinay_sajip@yahoo.co.uk>
     David Schein
+    Bernd Schlapsi
     scott@staplefish.com
     Ilya Semenov <semenov@inetss.com>
     serbaut@gmail.com

django/forms/models.py

@@ -41,6 +41,7 @@ def save_instance(form, instance, fields=None, fail_message='saved',
         raise ValueError("The %s could not be %s because the data didn't"
                          " validate." % (opts.object_name, fail_message))
     cleaned_data = form.cleaned_data
+    file_field_list = []
     for f in opts.fields:
         if not f.editable or isinstance(f, models.AutoField) \
                 or not f.name in cleaned_data:
@@ -49,7 +50,16 @@ def save_instance(form, instance, fields=None, fail_message='saved',
             continue
         if exclude and f.name in exclude:
             continue
+        # Defer saving file-type fields until after the other fields, so a
+        # callable upload_to can use the values from other fields.
+        if isinstance(f, models.FileField):
+            file_field_list.append(f)
+        else:
+            f.save_form_data(instance, cleaned_data[f.name])
+            
+    for f in file_field_list:
         f.save_form_data(instance, cleaned_data[f.name])
+        
     # Wrap up the saving of m2m data as a function.
     def save_m2m():
         opts = instance._meta

tests/modeltests/model_forms/models.py

@@ -99,6 +99,10 @@ class TextFile(models.Model):
         return self.description
 
 class ImageFile(models.Model):
+    def custom_upload_path(self, filename):
+        path = self.path or 'tests'
+        return '%s/%s' % (path, filename)
+    
     description = models.CharField(max_length=20)
     try:
         # If PIL is available, try testing PIL.
@@ -106,9 +110,10 @@ class ImageFile(models.Model):
         # for PyPy, you need to check for the underlying modules
         # If PIL is not available, this test is equivalent to TextFile above.
         from PIL import Image, _imaging
-        image = models.ImageField(storage=temp_storage, upload_to='tests')
+        image = models.ImageField(storage=temp_storage, upload_to=custom_upload_path)
     except ImportError:
-        image = models.FileField(storage=temp_storage, upload_to='tests')
+        image = models.FileField(storage=temp_storage, upload_to=custom_upload_path)
+    path = models.CharField(max_length=16, blank=True, default='')
 
     def __unicode__(self):
         return self.description
@@ -1122,6 +1127,15 @@ True
 <...FieldFile: tests/test3.png>
 >>> instance.delete()
 
+# Test callable upload_to behavior that's dependent on the value of another field in the model
+>>> f = ImageFileForm(data={'description': u'And a final one', 'path': 'foo'}, files={'image': SimpleUploadedFile('test4.png', image_data)})
+>>> f.is_valid()
+True
+>>> instance = f.save()
+>>> instance.image
+<...FieldFile: foo/test4.png>
+>>> instance.delete()
+
 # Media on a ModelForm ########################################################
 
 # Similar to a regular Form class you can define custom media to be used on