Django View Mixin for JSON Forms

This is a Mixin for Classbased Form Views which renders the POST result in JSON format.

Usage

Install the package (using virtualenv preferably) with pip install sierra-django-json-mixin-form or easy_install sierra-django-json-mixin-form

There is no need to configure anything in settings.py.

Import and use it (testmixins folder contains a simple usage)

# myapp/views.py
from sierra.dj.mixins.forms import JSONFormMixin

from django.views.generic.edit import FormView
from django import forms

from myapp.models import MyModel

# This can be any kind of form, from simple forms to ModelForms and beyond
# You can also define custom validation either on Model or the form (or both)
class MyModelForm(forms.ModelForm):
    class Meta:
        model = MyModel


# Extends JSONFormMixin before your FormView or any extension of it which
# does not returns an HttpResponse instance on form_valid and form_invalid
# methods
class MyFormView(JSONFormMixin, FormView):
    form_class = FormTest
    template_name = 'my-form.html'
    # success_url = Unused

Add this view to your urls.py and call it via javascript.:

# myproject/urls.py
from django.conf.urls import patterns, include, url
from myapp.views import MyFormView

urlpatterns = patterns('',
    # ...
    url(r'^myform.json$', MyFormView.as_view(), name='my-form'),
)

NOTE: This example is writing using jQuery, but you don't actually need any Javascript library. I'm using jQuery just because it is easier.:

# myscript.js
$("#form").on('submit', function(){
    $.post("/myform.json", $(this).serialize(), function(response){
        if(response.success){
            // Horray!
        }else{
            // Do something with response.errors/non_field_errors
        }
    }, 'json');
    return false;
});

Mixin options

When writing your view you can set a bunch of attributes to change what it will return in JSON:

• json_encoding = 'utf-8' # Encoding used to render JSON
• errors_key = 'errors' # Key used to group all errors
• non_field_errors_key = 'non_field_errors' # Key used for errors non related to fields
• include_success = False # In case of valid form, this will include a "success": true on JSON
• sucess_key = 'success' # Key used to signal success

To set any of these attributes, just set as class variable (or using self.<option>):

class MyView(JSONFormMixin, FormView):
    json_encoding = 'iso-8859-1'
    success_key = 'done'

Note that hidden fields are not supposed to not validate since they usually are set by the server, but anyway...

Response content

Depending on form validation JSON return will be something like this:

{
    'success': bool, // Set only when View.include_success = True (default)
    'non_field_errors': [error_list], // Same as form.non_field_errors
    'errors': { // May be empty
        'field_name':{
            'name': 'field_name',
            'id': 'id_'+field_name, // Default Django HTML field ID
            'errors': [field_error_list] // Same as form.field.errors
        }
    }
}