Question

I have an application where I allow importing from CSV files. A list of Libraries are contained in the CSV file. I need to first parse them into a list of Library instances, display them on another page, after user clicks “confirm”, these libraries are saved.

Here is my Form:

class LibCsvForm(forms.Form):
    lib_csv  = forms.FileField(label='CSV file')

class LibListForm(forms.Form):
    def __init__(self, *args, **kwargs):
        new_libs = kwargs.pop('new_libs')
        super(LibListForm, self).__init__(*args, **kwargs)
        self.fields['new_libs'] = new_libs

And my views:

def import_lib_csv(request):
    if request.method == 'POST':
        form = LibCsvForm(request.POST, request.FILES)
        if form.is_valid():
            raw = request.FILES['lib_csv'].read()
            new_libs = []
            # Process string 'raw' and add instances of Library to new_libs
            context = RequestContext(request, {'form': LibListForm(new_libs=new_libs)})
            context.update(csrf(request))
            return render_to_response('master/library.csv.confirm.html', context)
    else:
        form = LibCsvForm()
    variables = RequestContext(request, { 'form': form })
    return render_to_response('master/library.csv.html', variables)

A LibCsvForm is just for user to upload a file. Method “import_lib_csv” is to read the file, create instances, and pass them to another form LibListForm, which contains only ‘new_libs’. After the user clicks ‘confirm’, I would like to get this list and save the objects.

The problem is that, in the template:

{{ form.new_libs }}
{% for lib in new_libs %}
     {{ lib.id }}
{% endfor %}

It does not show anything. I think I did not pass the ‘new_libs’ into the form properly. Could anybody help? Thanks.

---

Edit:

Thanks, Rohan. I modified it as you mention. Now the library list can be displayed on in the template. ‘new_libs’ is a list of Library instances.

But when I click “confirm”, it reports error. Here is my method to save:

def save_lib_list(request):
    if request.POST:
        form = LibListForm(request.POST)
        print form.cleaned_data['new_libs']
    variables = RequestContext(request, {
        'lib_list': Library.objects.all()
    })
    return render_to_response('master/library.list.html', variables) 

Django says

"Exception Type:    KeyError
Exception Value:    'new_libs' "

My template is:

<form method="post" action="/library/savelist/" class="well">
    {% csrf_token %}
    <legend>Libraries to import</legend>
    {% for lib in new_libs %}
        {{ lib.id }}
    {% endfor %}
</form>

I think i miss something here, but not know how to solve…

---

Solved:

Save the content of uploaded CSV file on the server first. Set the path of this file as a hidden field in the LibListForm:

tmp_lib_file = forms.CharField(widget=forms.HiddenInput(), initial='tmp.lib')

Then when user clicks ‘confirm’, parse the file again and get instances of Library, save them.

Answer 1

You should add the new_libs in the template context if you want to use it in template.

context = RequestContext(request, {'form': LibListForm(new_libs=new_libs), 'new_libs': new_libs})

Also, what is the type of new_libs that you pass to LibListForm? If its not a proper field type if would not be displayed/processed properly.

Update after question edit:

• The error suggests that there is no new_fields key in the form.cleaned_data. The form should have a field with that name. new_field doesn’t seem to be a form field.
• Also your template doesn’t have form fields?