As ars and Diarmuid have pointed out, you can pass request.user into your form, and use it in validating the email. Diarmuid's code, however, is wrong. The code should actually read:

from django import forms

class UserForm(forms.Form):
    email_address = forms.EmailField(
        widget=forms.TextInput(
            attrs={
                'class': 'required'
            }
        )
    )

    def __init__(self, *args, **kwargs):
        self.user = kwargs.pop('user', None)
        super(UserForm, self).__init__(*args, **kwargs)

    def clean_email_address(self):
        email = self.cleaned_data.get('email_address')

        if self.user and self.user.email == email:
            return email

        if UserProfile.objects.filter(email=email).count():
            raise forms.ValidationError(
                u'That email address already exists.'
            )

        return email

Then, in your view, you can use it like so:

def someview(request):
    if request.method == 'POST':
        form = UserForm(request.POST, user=request.user)
        if form.is_valid():
            # Do something with the data
            pass
    else:
        form = UserForm(user=request.user)
    # Rest of your view follows

Note that you should pass request.POST as a keyword argument, since your constructor expects 'user' as the first positional argument.

Doing it this way, you need to pass user as a keyword argument. You can either pass request.POST as a positional argument, or a keyword argument (via data=request.POST).

I have some sample code from a recent project of mine that I believe may help you. In this example, super users can edit every field, while everyone else has the "description" field excluded.

Note that I think it's expected that you return a Form class from get_form, which could be why yours was not working quite right.

Here's the example:

class EventForm(forms.ModelForm):
    class Meta:
        model = models.Event
        exclude = ['description',]

class EventAdminForm(forms.ModelForm):
    class Meta:
        model = models.Event

class EventAdmin(admin.ModelAdmin):

    def get_form(self, request, obj=None, **kwargs):
        if request.user.is_superuser:
            return EventAdminForm
        else:
            return EventForm 

admin.site.register(models.Event, EventAdmin)

This is nothing to do with forms or GET.

You have used the render_to_response shortcut, which takes two positional arguments: template and context. But you have passed three arguments, putting the request first; that shortcut does not take the request.

I think you meant to just use the render shortcut, which does take the request first.

return render(request,'template.html', context)

Using a form in a view pretty much explains it.

The standard pattern for processing a form in a view looks like this:

def contact(request):
    if request.method == 'POST': # If the form has been submitted...
        form = ContactForm(request.POST) # A form bound to the POST data
        if form.is_valid(): # All validation rules pass
            # Process the data in form.cleaned_data
            # ...

            print form.cleaned_data['my_form_field_name']

            return HttpResponseRedirect('/thanks/') # Redirect after POST
    else:
        form = ContactForm() # An unbound form

    return render_to_response('contact.html', {
        'form': form,
    })

I can't imagine where you are having trouble. Simply replace request.POST with request.GET when you instantiate the form.