Django form with filefield loses the file when editing an instance - django

Question

I'm trying to make a form that can be used to make a new instance of "LearningObjects" as well as edit existing instances. It seems to work fine except that when I'm editing an existing instance I lose the filefield. Since it is a required field it asks me to upload a new file and obviously I don't always want to do that.
Form.py
class LearningObjectuploadform(forms.ModelForm, edit):
level = forms.ModelMultipleChoiceField(widget=forms.CheckboxSelectMultiple,queryset=None,required=False)
agebracket =forms.ModelMultipleChoiceField(widget=forms.CheckboxSelectMultiple,queryset=None,required=False)
pathway = forms.ModelMultipleChoiceField(widget=forms.CheckboxSelectMultiple,queryset=None,required=False)
class Meta:
model = LearningObject
fields =['title','archivefile','description','tags','pathway','level','subject','agebracket']
def __init__(self, *args, **kwargs):
super(LearningObjectuploadform, self).__init__(*args, **kwargs)
self.fields['level'].queryset = AssoeLevel.objects.all()
self.fields['pathway'].queryset = AssoePathway.objects.all()
self.fields['agebracket'].queryset = AgeBracket.objects.all()
View.py
def createLearningobject(request,learningobject_pk=False):
if request.method == 'GET':
if learningobject_pk:
print learningobject_pk
instance = LearningObject.objects.get( pk=learningobject_pk)
print instance
form = LearningObjectuploadform(request.POST or None, request.FILES or None, instance=instance)
else:
form = LearningObjectuploadform()
else:
form = LearningObjectuploadform(request.POST, request.FILES)
if form.is_valid():
learningobject = request.FILES['archivefile']
title = form.cleaned_data['title']
description = form.cleaned_data['description']
tags = form.cleaned_data['tags']
levels = form.cleaned_data['level']
pathways = form.cleaned_data['pathway']
agebrackets = form.cleaned_data['agebracket']
post = LearningObject.objects.create(archivefile=learningobject,title=title, description=description)
for tag in tags:
post.tags.add(tag)
for level in levels:
post.level.add(level.pk)
for pathway in pathways:
post.pathway.add(pathway.pk)
for agebracket in agebrackets:
post.agebracket.add(agebracket.pk)
post.save()
return HttpResponseRedirect(reverse('index', ))
else:
print "form not valid"
return render(request, 'mediamanager/edit_learningobject.html', {'form': form,})
Models.py
class DefaultResource(models.Model):
#
# This class is the parent class for all resources in the media manager
#
title = models.CharField(max_length=100)
created_date = models.DateTimeField(auto_now_add=True, auto_now=False)
edited_date = models.DateTimeField(auto_now_add=False,auto_now=True)
level = models.ManyToManyField(AssoeLevel)
agebracket= models.ManyToManyField(AgeBracket)
pathway= models.ManyToManyField(AssoePathway)
tags = TaggableManager()
slug = models.SlugField(max_length=100,editable=False,blank=True)
updownvotes = RatingField(can_change_vote=True)
views = models.DecimalField(max_digits=20,decimal_places=2,default=0,blank=True)
score = models.DecimalField(max_digits=20,decimal_places=4,default=0,blank=True)
icon = models.CharField(max_length=254,editable=False,blank=True)
subject = models.ManyToManyField(AssoeSubjects)
#def return_tags(self):
# taglist = self.tags.names()
# return taglist
def calculate_score(self):
score = float(self.updownvotes.likes) - float(self.updownvotes.dislikes)
score = score + (float(self.views)**(float(1)/float(2)))
self.score = score
rounded_score = int(round(self.score))
if rounded_score < -1:
return -1
else:
return rounded_score
def __unicode__ (self):
return self.title
def save(self, *args, **kwargs):
self.calculate_score()
if not self.id:
self.slug = slugify(self.title)
super(DefaultResource, self).save(*args, **kwargs)
class LearningObject(DefaultResource):
archivefile = models.FileField(upload_to='static/learningobject/archivefiles/%Y/%m/%d')
indexpath = models.CharField(max_length=254,editable=False,blank=True)
description = models.TextField(blank=True)
def unpackarchive(self):
archive = self.archivefile
filename = os.path.basename(str(archive))
folder = str(filename).split(".")[0]
print folder
index_found = "False"
with zipfile.ZipFile(archive,"r") as z:
for each in z.namelist():
if each == "index.html" or each == "index.htm":
index_found = "True"
else:
pass
if not index_found:
print "zip file does not contain a valid index.html file"
else:
path = os.path.join("static","learningobject","unpackedarchives",folder)
z.extractall(path)
self.findindex(path)
def findindex(self,path):
print path
for root, dirnames, filenames in os.walk(path):
for filename in fnmatch.filter(filenames, 'index.ht*'):
print filename
self.indexpath = os.path.join(root, filename)
print self.indexpath
def save(self, *args, **kwargs):
self.icon = "/static/images/icons/box.png"
self.unpackarchive()
super(LearningObject, self).save(*args, **kwargs)

Answer 1

I have faced similar problems with file uploads in django forms. This is what I hope should help you out(provided you are willing to alter the required attribute of the archivefile field.)
if request.method == 'GET':
if learningobject_pk:
print learningobject_pk
instance = LearningObject.objects.get( pk=learningobject_pk)
print instance
form = LearningObjectuploadform(request.POST or None, request.FILES or None, instance=instance)
form.base_fields['archivefile'].required = False
else:
form = LearningObjectuploadform()