Form Validation

Django has an excellent built-in form validation facility, and Piston can make good use of this.

You can decorate your actions with a @validate decorator, which receives 1 required argument, and one optional. The first argument is the form it will use for validation, and the second argument is the place to look for data. For the create action, this is ‘POST’ (default), and for update, it’s ‘PUT’.

For example:

from django import forms
from piston.utils import validate
from mysite.myapp.models import Blogpost

class BlogpostForm(forms.ModelForm):
    class Meta:
        model = Blogpost


@validate(BlogpostForm)
def create():
    pass

Or with a normal form:

from django import forms
from piston.utils import validate

class DataForm(forms.Form):
    data = forms.CharField(max_length=128)
    is_private = forms.BooleanField(default=True, required=False)

@validate(DataForm, 'PUT')
def update():
    pass

If data sent to an action that is decorated with a @validate action does not pass the forms is_clean method, Piston will return an error to the client, and will not execute the action. If the validation passes, then the form object is attached to the request object. Thus you can get to the form (and thus the cleaned_data) via request.form as in this example:

@validate(EchoForm, 'GET')
def read(self, request):
    return {'msg': request.form.cleaned_data['msg']}