I feel like you answered your own question : )

The docs on the check_password method are here:
https://docs.djangoproject.com/en/dev/topics/auth/customizing/#django.contrib.auth.models.AbstractBaseUser.check_password

success = user.check_password(request.POST['submitted_password'])
if success: 
   # do your email changing magic
else:
   return http.HttpResponse("Your password is incorrect") 
   # or more appropriately your template with errors

Since you’re already passing in request.user into your form constructor (looks like you’ve overriden __init__ for your own reasons) you could put all of your logic in the form without any trouble.

class MyForm(forms.Form):
     # ...
     password = forms.CharField(widget=forms.PasswordInput)
     
     def __init__(self, user, *args, **kwargs):
          super(MyForm, self).__init__(*args, **kwargs)
          self.user = user
          
     def clean_password(self):
         valid = self.user.check_password(self.cleaned_data['password'])
         if not valid:
             raise forms.ValidationError("Password Incorrect")
         return valid

update after seeing your forms

OK. The main problem is that __init__ has been defined twice, making the first statement useless. Second problem I see is that we’d be doing multiple queries for user when we really don’t have to.

We’ve strayed from your original question quite a bit, but hopefully this is a learning experience.

I’ve changed only a few things:

• Removed the extra __init__ definition
• Changed __init__ to accept a User instance instead of a text username
• Removed the query for User.objects.get(username=username) since we’re passing in a user object.

Just remember to pass the form constructor user=request.user instead of username=request.user.username

class EmailChangeForm(forms.Form):
    email = forms.EmailField(label='New E-mail', max_length=75)
    password = forms.CharField(widget=forms.PasswordInput)
    
    def __init__(self, user=None, *args, **kwargs):
        self.user = user
        super(EmailChangeForm, self).__init__(*args, **kwargs)
        
    def clean_password(self):
        valid = self.user.check_password(self.cleaned_data['password'])
        if not valid:
            raise forms.ValidationError("Password Incorrect")
        
    def clean_email(self):
        email = self.cleaned_data.get('email')
        
        # no need to query a user object if we're passing it in anyways.
        user = self.user 
        
        # Check if the new email address differs from the current email address.
        if user.email == email:
            raise forms.ValidationError('New email address cannot be the same \
                as your current email address')
                
        return email

Finally since we’re talking about good practice here, I’d recommend following through with Skirmantas suggestions about moving your current view code to a form method so you can simply call myform.send_confirmation_email.

Sounds like a good exercise!

thanks again to Yuji. It works when I don’t have in my first def __init__ the variable user. I also added in def clean_password the first 2 lines from the def clean_email

from django import forms
from django.db.models.loading import cache
from django.utils.translation import ugettext_lazy as _
from django.contrib.auth.models import User


class EmailChangeForm(forms.Form):

    email = forms.EmailField(label='New E-mail', max_length=75)
    password = forms.CharField(widget=forms.PasswordInput)

    def __init__(self, *args, **kwargs):
        self.user = user
        super(EmailChangeForm, self).__init__(*args, **kwargs)

    def clean_password(self):
        User = cache.get_model('auth', 'User')
        user = User.objects.get(username__exact=self.username)
        valid = user.check_password(self.cleaned_data['password'])
        if not valid:
            raise forms.ValidationError("Password Incorrect")
        return valid

    def __init__(self, username=None, *args, **kwargs):
        """Constructor.

        **Mandatory arguments**

        ``username``
            The username of the user that requested the email change.

        """
        self.username = username
        super(EmailChangeForm, self).__init__(*args, **kwargs)

    def clean_email(self):
        """Checks whether the new email address differs from the user's current
        email address.

        """
        email = self.cleaned_data.get('email')

        User = cache.get_model('auth', 'User')
        user = User.objects.get(username__exact=self.username)

        # Check if the new email address differs from the current email address.
        if user.email == email:
            raise forms.ValidationError('New email address cannot be the same \
                as your current email address')

        return email