Allow overriding login form via `WAGTAILADMIN_USER_LOGIN_FORM` setting

CHANGELOG.txt

@@ -24,6 +24,7 @@ Changelog
  * Added `heading` kwarg to `InlinePanel` to allow heading to be set independently of button label (Adrian Turjak)
  * The value type returned from a `StructBlock` can now be customised (LB (Ben Johnston))
  * Added `bgcolor` image operation (Karl Hobley)
+ * Added `WAGTAILADMIN_USER_LOGIN_FORM` setting for overriding the admin login form (Mike Dingjan)
  * Fix: Do not remove stopwords when generating slugs from non-ASCII titles, to avoid issues with incorrect word boundaries (Sævar Öfjörð Magnússon)
  * Fix: The PostgreSQL search backend now preserves ordering of the `QuerySet` when searching with `order_by_relevance=False` (Bertrand Bordage)
  * Fix: Using `modeladmin_register` as a decorator no longer replaces the decorated class with `None` (Tim Heap)

docs/advanced_topics/settings.rst

@@ -224,6 +224,13 @@ Dashboard
 This setting lets you change the number of items shown at 'Your most recent edits' on the dashboard.
 
 
+.. code-block:: python
+
+  WAGTAILADMIN_USER_LOGIN_FORM = 'users.forms.LoginForm'
+
+Allows the default ``LoginForm`` to be extended with extra fields.
+
+
 Images
 ------
 

docs/releases/2.0.rst

@@ -37,6 +37,7 @@ Other features
  * Added ``heading`` kwarg to ``InlinePanel`` to allow heading to be set independently of button label (Adrian Turjak)
  * The value type returned from a ``StructBlock`` can now be customised. See :ref:`custom_value_class_for_structblock` (LB (Ben Johnston))
  * Added `bgcolor` image operation (Karl Hobley)
+ * Added ``WAGTAILADMIN_USER_LOGIN_FORM`` setting for overriding the admin login form (Mike Dingjan)
 
 Bug fixes
 ~~~~~~~~~

wagtail/admin/forms.py

@@ -64,19 +64,24 @@ class EmailLinkChooserForm(forms.Form):
 
 class LoginForm(AuthenticationForm):
     username = forms.CharField(
-        max_length=254,
-        widget=forms.TextInput(attrs={'tabindex': '1'}),
-    )
+        max_length=254, widget=forms.TextInput(attrs={'tabindex': '1'}))
+
     password = forms.CharField(
-        widget=forms.PasswordInput(attrs={'placeholder': ugettext_lazy("Enter password"),
-                                          'tabindex': '2',
-                                          }),
-    )
+        widget=forms.PasswordInput(attrs={
+            'tabindex': '2',
+            'placeholder': ugettext_lazy("Enter password"),
+        }))
 
     def __init__(self, request=None, *args, **kwargs):
         super().__init__(request=request, *args, **kwargs)
-        self.fields['username'].widget.attrs['placeholder'] = ugettext_lazy("Enter your %s") \
-            % self.username_field.verbose_name
+        self.fields['username'].widget.attrs['placeholder'] = (
+            ugettext_lazy("Enter your %s") % self.username_field.verbose_name)
+
+    @property
+    def extra_fields(self):
+        for field_name, field in self.fields.items():
+            if field_name not in ['username', 'password']:
+                yield field_name, field
 
 
 class PasswordResetForm(PasswordResetForm):

wagtail/admin/templates/wagtailadmin/login.html

@@ -56,6 +56,18 @@
                         <p class="help"><a href="{% url 'wagtailadmin_password_reset' %}">{% trans "Forgotten it?" %}</a></p>
                     {% endif %}
                 </li>
+
+                {% block extra_fields %}
+                {% for field_name, field in form.extra_fields %}
+                <li class="full">
+                    {{ field.label_tag }}
+                    <div class="field iconfield">
+                        {{ field }}
+                    </div>
+                </li>
+                {% endfor %}
+                {% endblock extra_fields %}
+
                 {% comment %}
                     Removed until functionality exists
                     <li class="checkbox">

wagtail/admin/tests/test_forms.py

@@ -0,0 +1,18 @@
+from django.forms.fields import CharField
+from django.test import TestCase
+
+from wagtail.admin.forms import LoginForm
+
+
+class CustomLoginForm(LoginForm):
+    captcha = CharField(
+        label='Captcha', help_text="should be in extra_fields()")
+
+
+class TestLoginForm(TestCase):
+
+    def test_extra_fields(self):
+        form = CustomLoginForm()
+        self.assertEqual(list(form.extra_fields), [
+            ('captcha', form.fields['captcha'])
+        ])

wagtail/admin/views/account.py

@@ -17,6 +17,15 @@ from wagtail.admin.utils import get_available_admin_languages
 from wagtail.core.models import UserPagePermissionsProxy
 from wagtail.users.forms import NotificationPreferencesForm, PreferredLanguageForm
 from wagtail.users.models import UserProfile
+from wagtail.utils.loading import get_custom_form
+
+
+def get_user_login_form():
+    form_setting = 'WAGTAILADMIN_USER_LOGIN_FORM'
+    if hasattr(settings, form_setting):
+        return get_custom_form(form_setting)
+    else:
+        return forms.LoginForm
 
 
 # Helper functions to check password management settings to enable/disable views as appropriate.
@@ -136,7 +145,7 @@ def login(request):
         return auth_views.login(
             request,
             template_name='wagtailadmin/login.html',
-            authentication_form=forms.LoginForm,
+            authentication_form=get_user_login_form(),
             extra_context={
                 'show_password_reset': password_reset_enabled(),
                 'username_field': get_user_model().USERNAME_FIELD,

wagtail/users/views/users.py

@@ -1,13 +1,12 @@
 from django.conf import settings
 from django.contrib.auth import get_user_model
-from django.core.exceptions import ImproperlyConfigured
 from django.db.models import Q
 from django.shortcuts import get_object_or_404, redirect, render
 from django.urls import reverse
-from django.utils.module_loading import import_string
 from django.utils.translation import ugettext as _
 from django.views.decorators.vary import vary_on_headers
 
+from wagtail.utils.loading import get_custom_form
 from wagtail.utils.pagination import paginate
 from wagtail.admin import messages
 from wagtail.admin.forms import SearchForm
@@ -28,20 +27,10 @@ change_user_perm = "{0}.change_{1}".format(AUTH_USER_APP_LABEL, AUTH_USER_MODEL_
 delete_user_perm = "{0}.delete_{1}".format(AUTH_USER_APP_LABEL, AUTH_USER_MODEL_NAME.lower())
 
 
-def get_custom_user_form(form_setting):
-    try:
-        return import_string(getattr(settings, form_setting))
-    except ImportError:
-        raise ImproperlyConfigured(
-            "%s refers to a form '%s' that is not available" %
-            (form_setting, getattr(settings, form_setting))
-        )
-
-
 def get_user_creation_form():
     form_setting = 'WAGTAIL_USER_CREATION_FORM'
     if hasattr(settings, form_setting):
-        return get_custom_user_form(form_setting)
+        return get_custom_form(form_setting)
     else:
         return UserCreationForm
 
@@ -49,7 +38,7 @@ def get_user_creation_form():
 def get_user_edit_form():
     form_setting = 'WAGTAIL_USER_EDIT_FORM'
     if hasattr(settings, form_setting):
-        return get_custom_user_form(form_setting)
+        return get_custom_form(form_setting)
     else:
         return UserEditForm
 

wagtail/utils/loading.py

@@ -0,0 +1,14 @@
+from django.conf import settings
+from django.core.exceptions import ImproperlyConfigured
+from django.utils.module_loading import import_string
+
+
+def get_custom_form(form_setting):
+    """Return custom form class if defined and available"""
+    try:
+        return import_string(getattr(settings, form_setting))
+    except ImportError:
+        raise ImproperlyConfigured(
+            "%s refers to a form '%s' that is not available" %
+            (form_setting, getattr(settings, form_setting))
+        )