hidden id

hidden_id.py

#from models.py
class DataLayer(Named, Authored, Dated, Noted):
    geometry_type = models.CharField(max_length=50, null=True, blank=True)
    srs = models.CharField(max_length=50, null=True, blank=True)
    files = models.ManyToManyField('DataFile', null=True, blank=True )
    layer_id = models.AutoField(primary_key=True)
    def __unicode__(self):
        return "DataLayer: %s" % self.name

#from forms.py
class LayerReviewForm(forms.ModelForm):
    """For editing and configuring the layer information for each layer."""
    data_file_id = forms.IntegerField(
            widget=forms.HiddenInput,
            )

    class Meta:
        model = DataLayer

       	fields = ['name', 'notes', 'geometry_type', 'srs']

#from models.py
class DataFile(Dated):
    """Data files represent individual file uploads.
    They are used to construct DataLayers.

    """
    file = models.FileField(upload_to=get_upload_path)
    upload = models.ForeignKey('UploadEvent', null=True, blank=True)
    def get_upload_path(self, filename):
        return 'uploads/%s/%s' % (self.upload.user.username, filename)
    def __unicode__(self):
        return "DataFile: %s" % self.file.url
    def get_layer_data(self):
        data = {}
        f = self.file
        zip_file = zipfile.ZipFile(f)
        contents = zip_file.namelist()
        proj = [n for n in contents if '.prj' in n]
        if proj:
            # guess the srs
            proj_text = zip_file.open( proj[0] ).read()
            data['notes'] = proj_text
            data['srs'] = ''
        else:
            data['srs'] = ''
        # give a default name
        basename = os.path.splitext(contents[0])[0]
        data['name'] = basename
        f.close()
        # get the id for the hidden field in the form
        data['data_file_id'] = self.id
        return data




#from views.py
@login_required
def review(request):
    """A view for uploading new data.
    """

    user=User.objects.get(username='carlos')
    if request.method == 'POST': # someone is giving us data
        formset = LayerReviewFormSet(request.POST)
        if formset.is_valid():
        		for form in formset:
                    # get the DataFile id from the form data
                    data_file_id = form.cleaned_data['data_file_id']
                    # now get the actual object associated with that id
                    data_file = DataFile.objects.get(id=data_file_id)
                    srs = form.cleaned_data['srs']
                    layer = DataLayer(srs = srs)
                    layer = form.save(commit=False)
                    layer.author = user
                    layer.save() # the DataLayer must exist before we can add
                    # relations to it
                    # add the relation
                    layer.files.add( data_file )
                    # resave the layer
                    layer.save()

    else: # we are asking them to review data
        # get the last upload of this user
        upload = UploadEvent.objects.filter(user=user).order_by('-date')[0]
        data_files = DataFile.objects.filter(upload=upload)
        layer_data = [ f.get_layer_data() for f in data_files ]
        formset = LayerReviewFormSet( initial=layer_data )

    c = {
            'formset':formset,
            }
    return render_to_response(
            'webfinches/review.html',
            RequestContext(request, c),
            )