Allow plugins to disable and pre-fill questions and contact form fields (#1824)

Co-authored-by: Raphael Michel <michel@rami.io>
Co-authored-by: Raphael Michel <mail@raphaelmichel.de>

doc/development/api/general.rst

@@ -34,7 +34,7 @@ Frontend
 --------
 
 .. automodule:: pretix.presale.signals
-   :members: html_head, html_footer, footer_link, front_page_top, front_page_bottom, front_page_bottom_widget, fee_calculation_for_cart, contact_form_fields, question_form_fields, checkout_confirm_messages, checkout_confirm_page_content, checkout_all_optional, html_page_header, sass_preamble, sass_postamble, render_seating_plan, checkout_flow_steps, position_info, position_info_top, item_description, global_html_head, global_html_footer, global_html_page_header
+   :members: html_head, html_footer, footer_link, front_page_top, front_page_bottom, front_page_bottom_widget, fee_calculation_for_cart, contact_form_fields, question_form_fields, contact_form_fields_overrides, question_form_fields_overrides, checkout_confirm_messages, checkout_confirm_page_content, checkout_all_optional, html_page_header, sass_preamble, sass_postamble, render_seating_plan, checkout_flow_steps, position_info, position_info_top, item_description, global_html_head, global_html_footer, global_html_page_header
 
 
 .. automodule:: pretix.presale.signals

src/pretix/base/views/mixins.py

@@ -14,6 +14,7 @@ from pretix.base.models import (
     CartPosition, InvoiceAddress, OrderPosition, Question, QuestionAnswer,
     QuestionOption,
 )
+from pretix.presale.signals import contact_form_fields_overrides
 
 
 class BaseQuestionsViewMixin:
@@ -34,6 +35,9 @@ class BaseQuestionsViewMixin:
     def _positions_for_questions(self):
         raise NotImplementedError()
 
+    def get_question_override_sets(self, position):
+        return []
+
     @cached_property
     def forms(self):
         """
@@ -62,6 +66,23 @@ class BaseQuestionsViewMixin:
                     self.request.event.settings.attendee_addresses_asked
                 ))
             )
+
+            override_sets = self.get_question_override_sets(cr)
+            for overrides in override_sets:
+                for question_name, question_field in form.fields.items():
+                    if hasattr(question_field, 'question'):
+                        if question_field.question.identifier in overrides:
+                            if 'initial' in overrides[question_field.question.identifier]:
+                                question_field.initial = overrides[question_field.question.identifier]['initial']
+                            if 'disabled' in overrides[question_field.question.identifier]:
+                                question_field.disabled = overrides[question_field.question.identifier]['disabled']
+                    else:
+                        if question_name in overrides:
+                            if 'initial' in overrides[question_name]:
+                                question_field.initial = overrides[question_name]['initial']
+                            if 'disabled' in overrides[question_name]:
+                                question_field.disabled = overrides[question_name]['disabled']
+
             if len(form.fields) > 0:
                 formlist.append(form)
         return formlist
@@ -213,24 +234,47 @@ class OrderQuestionsViewMixin(BaseQuestionsViewMixin):
             self.order.total != Decimal('0.00') or not self.request.event.settings.invoice_address_not_asked_free
         )
 
+    @cached_property
+    def _contact_override_sets(self):
+        override_sets = [
+            resp for recv, resp in contact_form_fields_overrides.send(
+                self.request.event,
+                request=self.request,
+                order=self.order,
+            )
+        ]
+        for override in override_sets:
+            for k in override:
+                # We don't want initial values to be modified, they should come from the order directly
+                override[k].pop('initial', None)
+        return override_sets
+
     @cached_property
     def invoice_form(self):
         if not self.address_asked and self.request.event.settings.invoice_name_required:
-            return self.invoice_name_form_class(
+            f = self.invoice_name_form_class(
                 data=self.request.POST if self.request.method == "POST" else None,
                 event=self.request.event,
                 instance=self.invoice_address, validate_vat_id=False,
                 all_optional=self.all_optional
             )
-        if self.address_asked:
+        elif self.address_asked:
-            return self.invoice_form_class(
+            f = self.invoice_form_class(
                 data=self.request.POST if self.request.method == "POST" else None,
                 event=self.request.event,
                 instance=self.invoice_address, validate_vat_id=False,
                 all_optional=self.all_optional,
             )
         else:
-            return forms.Form(data=self.request.POST if self.request.method == "POST" else None)
+            f = forms.Form(data=self.request.POST if self.request.method == "POST" else None)
+
+        override_sets = self._contact_override_sets
+        for overrides in override_sets:
+            for fname, val in overrides.items():
+                if 'disabled' in val and fname in f.fields:
+                    f.fields[fname].disabled = val['disabled']
+
+        return f
 
     def get_context_data(self, **kwargs):
         ctx = super().get_context_data(**kwargs)

src/pretix/presale/checkoutflow.py

@@ -32,7 +32,9 @@ from pretix.presale.forms.checkout import (
 )
 from pretix.presale.signals import (
     checkout_all_optional, checkout_confirm_messages, checkout_flow_steps,
-    contact_form_fields, order_meta_from_request, question_form_fields,
+    contact_form_fields, contact_form_fields_overrides,
+    order_meta_from_request, question_form_fields,
+    question_form_fields_overrides,
 )
 from pretix.presale.views import (
     CartMixin, get_cart, get_cart_is_free, get_cart_total,
@@ -423,6 +425,16 @@ class QuestionsStep(QuestionsViewMixin, CartMixin, TemplateFlowStep):
                 return True
         return False
 
+    @cached_property
+    def _contact_override_sets(self):
+        return [
+            resp for recv, resp in contact_form_fields_overrides.send(
+                self.request.event,
+                request=self.request,
+                order=None,
+            )
+        ]
+
     @cached_property
     def contact_form(self):
         wd = self.cart_session.get('widget_data', {})
@@ -433,14 +445,36 @@ class QuestionsStep(QuestionsViewMixin, CartMixin, TemplateFlowStep):
             )
         }
         initial.update(self.cart_session.get('contact_form_data', {}))
+
+        override_sets = self._contact_override_sets
+        for overrides in override_sets:
+            initial.update({
+                k: v['initial'] for k, v in overrides.items() if 'initial' in v
+            })
+
         f = ContactForm(data=self.request.POST if self.request.method == "POST" else None,
                         event=self.request.event,
                         request=self.request,
                         initial=initial, all_optional=self.all_optional)
         if wd.get('email', '') and wd.get('fix', '') == "true":
             f.fields['email'].disabled = True
+
+        for overrides in override_sets:
+            for fname, val in overrides.items():
+                if 'disabled' in val and fname in f.fields:
+                    f.fields[fname].disabled = val['disabled']
+
         return f
 
+    def get_question_override_sets(self, cart_position):
+        return [
+            resp for recv, resp in question_form_fields_overrides.send(
+                self.request.event,
+                position=cart_position,
+                request=self.request
+            )
+        ]
+
     @cached_property
     def eu_reverse_charge_relevant(self):
         return any([p.item.tax_rule and (p.item.tax_rule.eu_reverse_charge or p.item.tax_rule.custom_rules)
@@ -466,6 +500,13 @@ class QuestionsStep(QuestionsViewMixin, CartMixin, TemplateFlowStep):
         else:
             wd_initial = {}
         initial = dict(wd_initial)
+
+        override_sets = self._contact_override_sets
+        for overrides in override_sets:
+            initial.update({
+                k: v['initial'] for k, v in overrides.items() if 'initial' in v
+            })
+
         if not self.address_asked and self.request.event.settings.invoice_name_required:
             f = InvoiceNameForm(data=self.request.POST if self.request.method == "POST" else None,
                                 event=self.request.event,
@@ -483,6 +524,12 @@ class QuestionsStep(QuestionsViewMixin, CartMixin, TemplateFlowStep):
         for name, field in f.fields.items():
             if wd_initial.get(name) and wd.get('fix', '') == 'true':
                 field.disabled = True
+
+        for overrides in override_sets:
+            for fname, val in overrides.items():
+                if 'disabled' in val and fname in f.fields:
+                    f.fields[fname].disabled = val['disabled']
+
         return f
 
     @cached_property

src/pretix/presale/signals.py

@@ -180,6 +180,21 @@ As with all plugin signals, the ``sender`` keyword argument will contain the eve
 argument will contain the request object.
 """
 
+contact_form_fields_overrides = EventPluginSignal(
+    providing_args=["request", "order"]
+)
+"""
+This signal allows you to override fields of the contact form that is presented during checkout
+and by default only asks for the email address. It is also being used for the invoice address
+form. You are supposed to return a dictionary of dictionaries with globally unique keys. The
+value-dictionary should contain one or more of the following keys: ``initial``, ``disabled``. The
+key of the dictionary should be the name of the form field.
+
+As with all plugin signals, the ``sender`` keyword argument will contain the event. A ``request``
+argument will contain the request object. The ``order`` argument is ``None`` during the checkout
+process and contains an order if the customer is trying to change an existing order.
+"""
+
 question_form_fields = EventPluginSignal(
     providing_args=["position"]
 )
@@ -196,6 +211,22 @@ later.
 As with all plugin signals, the ``sender`` keyword argument will contain the event.
 """
 
+question_form_fields_overrides = EventPluginSignal(
+    providing_args=["position", "request"]
+)
+"""
+This signal allows you to override fields of the questions form that is presented during checkout
+and by default only asks for the questions configured in the backend. You are supposed to return a
+dictionary of dictionaries with globally unique keys. The value-dictionary should contain one or
+more of the following keys: ``initial``, ``disabled``. The key of the dictionary should not be the
+question's form field name (``question_n``) but rather the questions ``identifier``.
+
+The ``position`` keyword argument will contain a ``CartPosition`` or ``OrderPosition`` object.
+
+As with all plugin signals, the ``sender`` keyword argument will contain the event. A ``request``
+argument will contain the request object.
+"""
+
 order_info = EventPluginSignal(
     providing_args=["order", "request"]
 )

src/pretix/presale/views/order.py

@@ -50,6 +50,7 @@ from pretix.helpers.safedownload import check_token
 from pretix.multidomain.urlreverse import build_absolute_uri, eventreverse
 from pretix.presale.forms.checkout import InvoiceAddressForm, QuestionsForm
 from pretix.presale.forms.order import OrderPositionChangeForm
+from pretix.presale.signals import question_form_fields_overrides
 from pretix.presale.views import (
     CartMixin, EventViewMixin, iframe_entry_view_wrapper,
 )
@@ -673,6 +674,20 @@ class OrderModify(EventViewMixin, OrderDetailMixin, OrderQuestionsViewMixin, Tem
             return []
         return super().positions
 
+    def get_question_override_sets(self, order_position):
+        override_sets = [
+            resp for recv, resp in question_form_fields_overrides.send(
+                self.request.event,
+                position=order_position,
+                request=self.request
+            )
+        ]
+        for override in override_sets:
+            for k in override:
+                # We don't want initial values to be modified, they should come from the order directly
+                override[k].pop('initial', None)
+        return override_sets
+
     def post(self, request, *args, **kwargs):
         failed = not self.save() or not self.invoice_form.is_valid()
         if failed: