Add the option to introduce rich-text placeholders (#4657)

* Add the option to introduce rich-text placeholders

* Add tests in test_format

* Add some css

* Block vs inline

* Some fixed css

* Update src/pretix/control/forms/event.py

Co-authored-by: Mira <weller@rami.io>

* Add missing docstring prat

---------

Co-authored-by: Mira <weller@rami.io>

src/pretix/base/email.py

@@ -35,6 +35,7 @@ from django.utils.translation import get_language, gettext_lazy as _
 from pretix.base.models import Event
 from pretix.base.signals import register_html_mail_renderers
 from pretix.base.templatetags.rich_text import markdown_compile_email
+from pretix.helpers.format import SafeFormatter, format_map
 
 from pretix.base.services.placeholders import (  # noqa
     get_available_placeholders, PlaceholderContext
@@ -79,7 +80,7 @@ class BaseHTMLMailRenderer:
         return self.identifier
 
     def render(self, plain_body: str, plain_signature: str, subject: str, order=None,
-               position=None) -> str:
+               position=None, context=None) -> str:
         """
         This method should generate the HTML part of the email.
 
@@ -88,6 +89,7 @@ class BaseHTMLMailRenderer:
         :param subject: The email subject.
         :param order: The order if this email is connected to one, otherwise ``None``.
         :param position: The order position if this email is connected to one, otherwise ``None``.
+        :param context: Context to use to render placeholders in the plain body
         :return: An HTML string
         """
         raise NotImplementedError()
@@ -134,8 +136,10 @@ class TemplateBasedMailRenderer(BaseHTMLMailRenderer):
     def compile_markdown(self, plaintext):
         return markdown_compile_email(plaintext)
 
-    def render(self, plain_body: str, plain_signature: str, subject: str, order, position) -> str:
+    def render(self, plain_body: str, plain_signature: str, subject: str, order, position, context) -> str:
         body_md = self.compile_markdown(plain_body)
+        if context:
+            body_md = format_map(body_md, context=context, mode=SafeFormatter.MODE_RICH_TO_HTML)
         htmlctx = {
             'site': settings.PRETIX_INSTANCE_NAME,
             'site_url': settings.SITE_URL,

src/pretix/base/services/mail.py

@@ -76,7 +76,7 @@ from pretix.base.services.tasks import TransactionAwareTask
 from pretix.base.services.tickets import get_tickets_for_order
 from pretix.base.signals import email_filter, global_email_filter
 from pretix.celery_app import app
-from pretix.helpers.format import format_map
+from pretix.helpers.format import SafeFormatter, format_map
 from pretix.helpers.hierarkey import clean_filename
 from pretix.multidomain.urlreverse import build_absolute_uri
 from pretix.presale.ical import get_private_icals
@@ -311,7 +311,13 @@ def mail(email: Union[str, Sequence[str]], subject: str, template: Union[str, La
             try:
                 if plain_text_only:
                     body_html = None
+                elif 'context' in inspect.signature(renderer.render).parameters:
+                    body_html = renderer.render(content_plain, signature, raw_subject, order, position, context)
                 elif 'position' in inspect.signature(renderer.render).parameters:
+                    # Backwards compatibility
+                    warnings.warn('Email renderer called without context argument because context argument is not '
+                                  'supported.',
+                                  DeprecationWarning)
                     body_html = renderer.render(content_plain, signature, raw_subject, order, position)
                 else:
                     # Backwards compatibility
@@ -323,6 +329,8 @@ def mail(email: Union[str, Sequence[str]], subject: str, template: Union[str, La
                 logger.exception('Could not render HTML body')
                 body_html = None
 
+        body_plain = format_map(body_plain, context, mode=SafeFormatter.MODE_RICH_TO_PLAIN)
+
         send_task = mail_send_task.si(
             to=[email] if isinstance(email, str) else list(email),
             cc=cc,
@@ -655,7 +663,7 @@ def render_mail(template, context):
     if isinstance(template, LazyI18nString):
         body = str(template)
         if context:
-            body = format_map(body, context)
+            body = format_map(body, context, mode=SafeFormatter.MODE_IGNORE_RICH)
     else:
         tpl = get_template(template)
         body = tpl.render(context)

src/pretix/base/services/placeholders.py

@@ -26,6 +26,7 @@ from decimal import Decimal
 
 from django.dispatch import receiver
 from django.utils.formats import date_format
+from django.utils.html import escape
 from django.utils.timezone import now
 from django.utils.translation import gettext_lazy as _
 
@@ -39,7 +40,8 @@ from pretix.base.settings import PERSON_NAME_SCHEMES, get_name_parts_localized
 from pretix.base.signals import (
     register_mail_placeholders, register_text_placeholders,
 )
-from pretix.helpers.format import SafeFormatter
+from pretix.base.templatetags.rich_text import markdown_compile_email
+from pretix.helpers.format import PlainHtmlAlternativeString, SafeFormatter
 
 logger = logging.getLogger('pretix.base.services.placeholders')
 
@@ -107,6 +109,91 @@ class SimpleFunctionalTextPlaceholder(BaseTextPlaceholder):
             return self._sample
 
 
+class BaseRichTextPlaceholder(BaseTextPlaceholder):
+    """
+    This is the base class for all placeholders which can render either to plain text
+    or to a rich HTML element.
+    """
+
+    def __init__(self, identifier, args):
+        self._identifier = identifier
+        self._args = args
+
+    @property
+    def identifier(self):
+        return self._identifier
+
+    @property
+    def required_context(self):
+        return self._args
+
+    @property
+    def is_block(self):
+        return False
+
+    def render(self, context):
+        return PlainHtmlAlternativeString(
+            self.render_plain(**{k: context[k] for k in self._args}),
+            self.render_html(**{k: context[k] for k in self._args}),
+            self.is_block,
+        )
+
+    def render_html(self, **kwargs):
+        """
+        HTML rendering of the placeholder. Should return "safe" HTML, i.e. everything needs to be
+        escaped.
+        """
+        raise NotImplementedError
+
+    def render_plain(self, **kwargs):
+        """
+        Plain text rendering of the placeholder.
+        """
+        raise NotImplementedError
+
+    def render_sample(self, event):
+        return PlainHtmlAlternativeString(
+            self.render_sample_plain(event=event),
+            self.render_sample_html(event=event),
+            self.is_block,
+        )
+
+    def render_sample_html(self, event):
+        raise NotImplementedError
+
+    def render_sample_plain(self, event):
+        raise NotImplementedError
+
+
+class SimpleButtonPlaceholder(BaseRichTextPlaceholder):
+    def __init__(self, identifier, args, url_func, text_func, sample_url_func, sample_text_func):
+        super().__init__(identifier, args)
+        self._url_func = url_func
+        self._text_func = text_func
+        self._sample_url_func = sample_url_func
+        self._sample_text_func = sample_text_func
+
+    def render_html(self, **context):
+        text = self._text_func(**{k: context[k] for k in self._args})
+        url = self._url_func(**{k: context[k] for k in self._args})
+        return f'<a href="{url}" class="button">{escape(text)}</a>'
+
+    def render_plain(self, **context):
+        text = self._text_func(**{k: context[k] for k in self._args})
+        url = self._url_func(**{k: context[k] for k in self._args})
+        return f'{text}: {url}'
+
+    def render_sample_html(self, event):
+        text = self._sample_text_func(event)
+        url = self._sample_url_func(event)
+        return f'<a href="{url}" class="button">{escape(text)}</a>'
+
+    def render_sample_plain(self, event):
+        text = self._sample_text_func(event)
+        url = self._sample_url_func(event)
+        return f'{text}: {url}'
+
+
 class PlaceholderContext(SafeFormatter):
     """
     Holds the contextual arguments and corresponding list of available placeholders for formatting
@@ -284,6 +371,27 @@ def base_placeholders(sender, **kwargs):
                 }
             ),
         ),
+        SimpleButtonPlaceholder(
+            'url_button', ['order', 'event'],
+            url_func=lambda order, event: build_absolute_uri(
+                event,
+                'presale:event.order.open', kwargs={
+                    'order': order.code,
+                    'secret': order.secret,
+                    'hash': order.email_confirm_secret()
+                }
+            ),
+            text_func=lambda order, event: _("View order details"),
+            sample_url_func=lambda event: build_absolute_uri(
+                event,
+                'presale:event.order.open', kwargs={
+                    'order': 'F8VVL',
+                    'secret': '6zzjnumtsx136ddy',
+                    'hash': '98kusd8ofsj8dnkd'
+                }
+            ),
+            sample_text_func=lambda event: _("View order details"),
+        ),
         SimpleFunctionalTextPlaceholder(
             'url_info_change', ['order', 'event'], lambda order, event: build_absolute_uri(
                 event,
@@ -348,6 +456,27 @@ def base_placeholders(sender, **kwargs):
                 }
             ),
         ),
+        SimpleButtonPlaceholder(
+            'url_button', ['event', 'position'],
+            url_func=lambda event, position: build_absolute_uri(
+                event,
+                'presale:event.order.position', kwargs={
+                    'order': position.order.code,
+                    'secret': position.web_secret,
+                    'position': position.positionid
+                }
+            ),
+            text_func=lambda event, position: _("View registration details"),
+            sample_url_func=lambda event: build_absolute_uri(
+                event,
+                'presale:event.order.position', kwargs={
+                    'order': 'F8VVL',
+                    'secret': '6zzjnumtsx136ddy',
+                    'position': '123'
+                }
+            ),
+            sample_text_func=lambda event: _("View registration details"),
+        ),
         SimpleFunctionalTextPlaceholder(
             'url_info_change', ['position', 'event'], lambda position, event: build_absolute_uri(
                 event,
@@ -603,8 +732,8 @@ def base_placeholders(sender, **kwargs):
 
 
 class FormPlaceholderMixin:
-    def _set_field_placeholders(self, fn, base_parameters):
-        placeholders = get_available_placeholders(self.event, base_parameters)
+    def _set_field_placeholders(self, fn, base_parameters, rich=False):
+        placeholders = get_available_placeholders(self.event, base_parameters, rich=rich)
         ht = format_placeholders_help_text(placeholders, self.event)
         if self.fields[fn].help_text:
             self.fields[fn].help_text += ' ' + str(ht)
@@ -615,7 +744,7 @@ class FormPlaceholderMixin:
         )
 
 
-def get_available_placeholders(event, base_parameters):
+def get_available_placeholders(event, base_parameters, rich=False):
     if 'order' in base_parameters:
         base_parameters.append('invoice_address')
         base_parameters.append('position_or_address')
@@ -624,6 +753,35 @@ def get_available_placeholders(event, base_parameters):
         if not isinstance(val, (list, tuple)):
             val = [val]
         for v in val:
+            if isinstance(v, BaseRichTextPlaceholder) and not rich:
+                continue
             if all(rp in base_parameters for rp in v.required_context):
                 params[v.identifier] = v
     return params
+
+
+def get_sample_context(event, context_parameters, rich=True):
+    context_dict = {}
+    lbl = _('This value will be replaced based on dynamic parameters.')
+    for k, v in get_available_placeholders(event, context_parameters, rich=rich).items():
+        sample = v.render_sample(event)
+        if isinstance(sample, PlainHtmlAlternativeString):
+            context_dict[k] = PlainHtmlAlternativeString(
+                sample.plain,
+                '<{el} class="placeholder placeholder-html" title="{title}">{html}</{el}>'.format(
+                    el='div' if sample.is_block else 'span',
+                    title=lbl,
+                    html=sample.html,
+                )
+            )
+        elif str(sample).strip().startswith('* ') or str(sample).startswith('  '):
+            context_dict[k] = '<div class="placeholder" title="{}">{}</div>'.format(
+                lbl,
+                markdown_compile_email(str(sample))
+            )
+        else:
+            context_dict[k] = '<span class="placeholder" title="{}">{}</span>'.format(
+                lbl,
+                escape(sample)
+            )
+    return context_dict

src/pretix/base/templates/pretixbase/email/base.html

@@ -131,6 +131,9 @@
             text-align: left;
             padding: 0;
         }
+        .content table td.align-right {
+            text-align: right;
+        }
 
         a.button {
             display: inline-block;
@@ -178,6 +181,9 @@
         pre, pre code {
             white-space: pre-line;
         }
+        .text-right, .content table td.text-right {
+            text-align: right;
+        }
 
         {% if rtl %}
             body {
@@ -186,6 +192,9 @@
             .content {
                 text-align: right;
             }
+            .text-right, .content table td.text-right {
+                text-align: left;
+            }
         {% endif %}
 
         {% block addcss %}{% endblock %}

src/pretix/base/templatetags/rich_text.py

@@ -305,6 +305,7 @@ def markdown_compile_email(source, allowed_tags=ALLOWED_TAGS, allowed_attributes
         source,
         extensions=[
             'markdown.extensions.sane_lists',
+            'markdown.extensions.tables',
             EmailNl2BrExtension(),
             LinkifyAndCleanExtension(
                 linker,

src/pretix/control/forms/event.py

@@ -1385,7 +1385,7 @@ class MailSettingsForm(FormPlaceholderMixin, SettingsForm):
         self.event.meta_values_cached = self.event.meta_values.select_related('property').all()
 
         for k, v in self.base_context.items():
-            self._set_field_placeholders(k, v)
+            self._set_field_placeholders(k, v, rich=k.startswith('mail_text_'))
 
         for k, v in list(self.fields.items()):
             if k.endswith('_attendee') and not event.settings.attendee_emails_asked:

src/pretix/control/views/event.py

@@ -62,7 +62,7 @@ from django.http import (
 from django.shortcuts import get_object_or_404, redirect
 from django.urls import reverse
 from django.utils.functional import cached_property
-from django.utils.html import escape
+from django.utils.html import conditional_escape
 from django.utils.http import url_has_allowed_host_and_scheme
 from django.utils.timezone import now
 from django.utils.translation import gettext, gettext_lazy as _, gettext_noop
@@ -100,9 +100,12 @@ from ...base.models.items import (
     Item, ItemCategory, ItemMetaProperty, Question, Quota,
 )
 from ...base.services.mail import prefix_subject
+from ...base.services.placeholders import get_sample_context
 from ...base.settings import LazyI18nStringList
 from ...helpers.compat import CompatDeleteView
-from ...helpers.format import format_map
+from ...helpers.format import (
+    PlainHtmlAlternativeString, SafeFormatter, format_map,
+)
 from ..logdisplay import OVERVIEW_BANLIST
 from . import CreateView, PaginationMixin, UpdateView
 
@@ -716,20 +719,7 @@ class MailSettingsPreview(EventPermissionRequiredMixin, View):
 
     # get all supported placeholders with dummy values
     def placeholders(self, item):
-        ctx = {}
-        for p in get_available_placeholders(self.request.event, MailSettingsForm.base_context[item]).values():
-            s = str(p.render_sample(self.request.event))
-            if s.strip().startswith('* '):
-                ctx[p.identifier] = '<div class="placeholder" title="{}">{}</div>'.format(
-                    _('This value will be replaced based on dynamic parameters.'),
-                    markdown_compile_email(s)
-                )
-            else:
-                ctx[p.identifier] = '<span class="placeholder" title="{}">{}</span>'.format(
-                    _('This value will be replaced based on dynamic parameters.'),
-                    escape(s)
-                )
-        return ctx
+        return get_sample_context(self.request.event, MailSettingsForm.base_context[item])
 
     def post(self, request, *args, **kwargs):
         preview_item = request.POST.get('item', '')
@@ -751,9 +741,15 @@ class MailSettingsPreview(EventPermissionRequiredMixin, View):
                                     bleach.clean(v), self.placeholders(preview_item), raise_on_missing=True
                                 ), highlight=True)
                             else:
-                                msgs[self.supported_locale[idx]] = markdown_compile_email(
-                                    format_map(v, self.placeholders(preview_item), raise_on_missing=True)
+                                placeholders = self.placeholders(preview_item)
+                                msgs[self.supported_locale[idx]] = format_map(
+                                    markdown_compile_email(
+                                        format_map(v, placeholders, raise_on_missing=True)
+                                    ),
+                                    placeholders,
+                                    mode=SafeFormatter.MODE_RICH_TO_HTML,
                                 )
+
                         except ValueError:
                             msgs[self.supported_locale[idx]] = '<div class="alert alert-danger">{}</div>'.format(
                                 PlaceholderValidator.error_message)
@@ -776,13 +772,18 @@ class MailSettingsRendererPreview(MailSettingsPreview):
     # get all supported placeholders with dummy values
     def placeholders(self, item):
         ctx = {}
-        for p in get_available_placeholders(self.request.event, MailSettingsForm.base_context[item]).values():
-            ctx[p.identifier] = escape(str(p.render_sample(self.request.event)))
+        for p in get_available_placeholders(self.request.event, MailSettingsForm.base_context[item], rich=True).values():
+            sample = p.render_sample(self.request.event)
+            if isinstance(sample, PlainHtmlAlternativeString):
+                ctx[p.identifier] = sample
+            else:
+                ctx[p.identifier] = conditional_escape(sample)
         return ctx
 
     def get(self, request, *args, **kwargs):
         v = str(request.event.settings.mail_text_order_placed)
-        v = format_map(v, self.placeholders('mail_text_order_placed'))
+        context = self.placeholders('mail_text_order_placed')
+        v = format_map(v, context)
         renderers = request.event.get_html_mail_renderers()
         if request.GET.get('renderer') in renderers:
             with rolledback_transaction():
@@ -800,7 +801,8 @@ class MailSettingsRendererPreview(MailSettingsPreview):
                     str(request.event.settings.mail_text_signature),
                     gettext('Your order: %(code)s') % {'code': order.code},
                     order,
-                    position=None
+                    position=None,
+                    context=context,
                 )
                 r = HttpResponse(v, content_type='text/html')
                 r._csp_ignore = True

src/pretix/control/views/orders.py

@@ -134,7 +134,7 @@ from pretix.control.signals import order_search_forms
 from pretix.control.views import PaginationMixin
 from pretix.helpers import OF_SELF
 from pretix.helpers.compat import CompatDeleteView
-from pretix.helpers.format import format_map
+from pretix.helpers.format import SafeFormatter, format_map
 from pretix.helpers.safedownload import check_token
 from pretix.presale.signals import question_form_fields
 
@@ -2351,7 +2351,7 @@ class OrderSendMail(EventPermissionRequiredMixin, OrderViewMixin, FormView):
                 'subject': mark_safe(_('Subject: {subject}').format(
                     subject=prefix_subject(order.event, escape(email_subject), highlight=True)
                 )),
-                'html': markdown_compile_email(email_content)
+                'html': format_map(markdown_compile_email(email_content), email_context, mode=SafeFormatter.MODE_RICH_TO_HTML)
             }
             return self.get(self.request, *self.args, **self.kwargs)
         else:

src/pretix/control/views/organizer.py

@@ -122,7 +122,7 @@ from pretix.control.views.mailsetup import MailSettingsSetupView
 from pretix.helpers import OF_SELF, GroupConcat
 from pretix.helpers.compat import CompatDeleteView
 from pretix.helpers.dicts import merge_dicts
-from pretix.helpers.format import format_map
+from pretix.helpers.format import SafeFormatter, format_map
 from pretix.helpers.urls import build_absolute_uri as build_global_uri
 from pretix.multidomain.urlreverse import build_absolute_uri
 from pretix.presale.forms.customer import TokenGenerator
@@ -357,9 +357,10 @@ class MailSettingsPreview(OrganizerPermissionRequiredMixin, View):
                                 highlight=True,
                             )
                         else:
-                            msgs[self.supported_locale[idx]] = markdown_compile_email(
-                                format_map(v, self.placeholders(preview_item))
-                            )
+                            placeholders = self.placeholders(preview_item)
+                            msgs[self.supported_locale[idx]] = format_map(markdown_compile_email(
+                                format_map(v, placeholders)
+                            ), placeholders, mode=SafeFormatter.MODE_RICH_TO_HTML)
 
         return JsonResponse({
             'item': preview_item,

src/pretix/control/views/vouchers.py

@@ -50,7 +50,7 @@ from django.http import (
 from django.shortcuts import redirect, render
 from django.urls import resolve, reverse
 from django.utils.functional import cached_property
-from django.utils.html import escape, format_html
+from django.utils.html import format_html
 from django.utils.safestring import mark_safe
 from django.utils.timezone import now
 from django.utils.translation import gettext_lazy as _
@@ -59,12 +59,12 @@ from django.views.generic import (
 )
 from django_scopes import scopes_disabled
 
-from pretix.base.email import get_available_placeholders
 from pretix.base.models import (
     CartPosition, LogEntry, Voucher, WaitingListEntry,
 )
 from pretix.base.models.vouchers import generate_codes
 from pretix.base.services.mail import prefix_subject
+from pretix.base.services.placeholders import get_sample_context
 from pretix.base.services.vouchers import vouchers_send
 from pretix.base.templatetags.rich_text import markdown_compile_email
 from pretix.base.views.tasks import AsyncFormView
@@ -74,7 +74,7 @@ from pretix.control.permissions import EventPermissionRequiredMixin
 from pretix.control.signals import voucher_form_class
 from pretix.control.views import PaginationMixin
 from pretix.helpers.compat import CompatDeleteView
-from pretix.helpers.format import format_map
+from pretix.helpers.format import SafeFormatter, format_map
 from pretix.helpers.models import modelcopy
 from pretix.multidomain.urlreverse import build_absolute_uri
 
@@ -549,22 +549,10 @@ class VoucherBulkMailPreview(EventPermissionRequiredMixin, View):
 
     # get all supported placeholders with dummy values
     def placeholders(self, item):
-        ctx = {}
         base_ctx = ['event', 'name']
         if item == 'send_message':
             base_ctx += ['voucher_list']
-        for p in get_available_placeholders(self.request.event, base_ctx).values():
-            s = str(p.render_sample(self.request.event))
-            if s.strip().startswith('* ') or s.startswith('  '):
-                ctx[p.identifier] = '<div class="placeholder" title="{}">{}</div>'.format(
-                    _('This value will be replaced based on dynamic parameters.'),
-                    markdown_compile_email(s)
-                )
-            else:
-                ctx[p.identifier] = '<span class="placeholder" title="{}">{}</span>'.format(
-                    _('This value will be replaced based on dynamic parameters.'),
-                    escape(s)
-                )
+        ctx = get_sample_context(self.request.event, base_ctx)
         return self.SafeDict(ctx)
 
     def post(self, request, *args, **kwargs):
@@ -579,9 +567,10 @@ class VoucherBulkMailPreview(EventPermissionRequiredMixin, View):
                 highlight=True
             )
         else:
-            msgs["all"] = markdown_compile_email(
-                format_map(request.POST.get(preview_item), self.placeholders(preview_item))
-            )
+            placeholders = self.placeholders(preview_item)
+            msgs["all"] = format_map(markdown_compile_email(
+                format_map(request.POST.get(preview_item), placeholders)
+            ), placeholders, mode=SafeFormatter.MODE_RICH_TO_HTML)
 
         return JsonResponse({
             'item': preview_item,

src/pretix/helpers/format.py

@@ -25,14 +25,29 @@ from string import Formatter
 logger = logging.getLogger(__name__)
 
 
+class PlainHtmlAlternativeString:
+    def __init__(self, plain, html, is_block=False):
+        self.plain = plain
+        self.html = html
+        self.is_block = is_block
+
+    def __repr__(self):
+        return f"PlainHtmlAlternativeString('{self.plain}', '{self.html}')"
+
+
 class SafeFormatter(Formatter):
     """
     Customized version of ``str.format`` that (a) behaves just like ``str.format_map`` and
     (b) does not allow any unwanted shenanigans like attribute access or format specifiers.
     """
-    def __init__(self, context, raise_on_missing=False):
+    MODE_IGNORE_RICH = 0
+    MODE_RICH_TO_PLAIN = 1
+    MODE_RICH_TO_HTML = 2
+
+    def __init__(self, context, raise_on_missing=False, mode=MODE_IGNORE_RICH):
         self.context = context
         self.raise_on_missing = raise_on_missing
+        self.mode = mode
 
     def get_field(self, field_name, args, kwargs):
         return self.get_value(field_name, args, kwargs), field_name
@@ -40,14 +55,22 @@ class SafeFormatter(Formatter):
     def get_value(self, key, args, kwargs):
         if not self.raise_on_missing and key not in self.context:
             return '{' + str(key) + '}'
-        return self.context[key]
+        r = self.context[key]
+        if isinstance(r, PlainHtmlAlternativeString):
+            if self.mode == self.MODE_IGNORE_RICH:
+                return '{' + str(key) + '}'
+            elif self.mode == self.MODE_RICH_TO_PLAIN:
+                return r.plain
+            elif self.mode == self.MODE_RICH_TO_HTML:
+                return r.html
+        return r
 
     def format_field(self, value, format_spec):
-        # Ignore format _spec
+        # Ignore format_spec
         return super().format_field(value, '')
 
 
-def format_map(template, context, raise_on_missing=False):
+def format_map(template, context, raise_on_missing=False, mode=SafeFormatter.MODE_IGNORE_RICH):
     if not isinstance(template, str):
         template = str(template)
-    return SafeFormatter(context, raise_on_missing).format(template)
+    return SafeFormatter(context, raise_on_missing, mode=mode).format(template)

src/pretix/plugins/sendmail/forms.py

@@ -79,8 +79,8 @@ class BaseMailForm(FormPlaceholderMixin, forms.Form):
             widget=I18nMarkdownTextarea, required=True,
             locales=event.settings.get('locales'),
         )
-        self._set_field_placeholders('subject', context_parameters)
-        self._set_field_placeholders('message', context_parameters)
+        self._set_field_placeholders('subject', context_parameters, rich=False)
+        self._set_field_placeholders('message', context_parameters, rich=True)
 
 
 class WaitinglistMailForm(BaseMailForm):
@@ -382,7 +382,7 @@ class RuleForm(FormPlaceholderMixin, I18nModelForm):
         )
 
         self._set_field_placeholders('subject', ['event', 'order', 'event_or_subevent'])
-        self._set_field_placeholders('template', ['event', 'order', 'event_or_subevent'])
+        self._set_field_placeholders('template', ['event', 'order', 'event_or_subevent'], rich=True)
 
         choices = [(e, l) for e, l in Order.STATUS_CHOICE if e != 'n']
         choices.insert(0, ('n__valid_if_pending', _('payment pending but already confirmed')))

src/pretix/plugins/sendmail/views.py

@@ -46,12 +46,10 @@ from django.shortcuts import get_object_or_404, redirect
 from django.template.loader import get_template
 from django.urls import reverse
 from django.utils.functional import cached_property
-from django.utils.html import escape
 from django.utils.timezone import now
 from django.utils.translation import gettext_lazy as _, ngettext
 from django.views.generic import DeleteView, FormView, ListView, TemplateView
 
-from pretix.base.email import get_available_placeholders
 from pretix.base.i18n import LazyI18nString, language
 from pretix.base.models import Checkin, LogEntry, Order, OrderPosition
 from pretix.base.models.event import SubEvent
@@ -63,7 +61,8 @@ from pretix.plugins.sendmail.tasks import (
 )
 
 from ...base.services.mail import prefix_subject
-from ...helpers.format import format_map
+from ...base.services.placeholders import get_sample_context
+from ...helpers.format import SafeFormatter, format_map
 from ...helpers.models import modelcopy
 from . import forms
 from .models import Rule, ScheduledMail
@@ -191,17 +190,15 @@ class BaseSenderView(EventPermissionRequiredMixin, FormView):
         if self.request.POST.get("action") != "send":
             for l in self.request.event.settings.locales:
                 with language(l, self.request.event.settings.region):
-                    context_dict = {}
-                    for k, v in get_available_placeholders(self.request.event, self.context_parameters).items():
-                        context_dict[k] = '<span class="placeholder" title="{}">{}</span>'.format(
-                            _('This value will be replaced based on dynamic parameters.'),
-                            escape(v.render_sample(self.request.event))
-                        )
-
+                    context_dict = get_sample_context(self.request.event, self.context_parameters)
                     subject = bleach.clean(form.cleaned_data['subject'].localize(l), tags=set())
                     preview_subject = prefix_subject(self.request.event, format_map(subject, context_dict), highlight=True)
                     message = form.cleaned_data['message'].localize(l)
-                    preview_text = markdown_compile_email(format_map(message, context_dict))
+                    preview_text = format_map(
+                        markdown_compile_email(format_map(message, context_dict)),
+                        context_dict,
+                        mode=SafeFormatter.MODE_RICH_TO_HTML,
+                    )
 
                     self.output[l] = {
                         'subject': _('Subject: {subject}').format(subject=preview_subject),
@@ -603,31 +600,6 @@ class CreateRule(EventPermissionRequiredMixin, CreateView):
         return super().form_invalid(form)
 
     def form_valid(self, form):
-        self.output = {}
-
-        if self.request.POST.get("action") == "preview":
-            for l in self.request.event.settings.locales:
-                with language(l, self.request.event.settings.region):
-                    context_dict = {}
-                    for k, v in get_available_placeholders(self.request.event, ['event', 'order',
-                                                                                'position_or_address']).items():
-                        context_dict[k] = '<span class="placeholder" title="{}">{}</span>'.format(
-                            _('This value will be replaced based on dynamic parameters.'),
-                            escape(v.render_sample(self.request.event))
-                        )
-
-                    subject = bleach.clean(form.cleaned_data['subject'].localize(l), tags=set())
-                    preview_subject = prefix_subject(self.request.event, format_map(subject, context_dict), highlight=True)
-                    template = form.cleaned_data['template'].localize(l)
-                    preview_text = markdown_compile_email(format_map(template, context_dict))
-
-                    self.output[l] = {
-                        'subject': _('Subject: {subject}').format(subject=preview_subject),
-                        'html': preview_text,
-                    }
-
-            return self.get(self.request, *self.args, **self.kwargs)
-
         messages.success(self.request, _('Your rule has been created.'))
 
         form.instance.event = self.request.event
@@ -685,17 +657,15 @@ class UpdateRule(EventPermissionRequiredMixin, UpdateView):
 
         for lang in self.request.event.settings.locales:
             with language(lang, self.request.event.settings.region):
-                placeholders = {}
-                for k, v in get_available_placeholders(self.request.event, ['event', 'order', 'position_or_address']).items():
-                    placeholders[k] = '<span class="placeholder" title="{}">{}</span>'.format(
-                        _('This value will be replaced based on dynamic parameters.'),
-                        escape(v.render_sample(self.request.event))
-                    )
-
+                placeholders = get_sample_context(self.request.event, ['event', 'order', 'position_or_address'])
                 subject = bleach.clean(self.object.subject.localize(lang), tags=set())
                 preview_subject = prefix_subject(self.request.event, format_map(subject, placeholders), highlight=True)
                 template = self.object.template.localize(lang)
-                preview_text = markdown_compile_email(format_map(template, placeholders))
+                preview_text = format_map(
+                    markdown_compile_email(format_map(template, placeholders)),
+                    placeholders,
+                    mode=SafeFormatter.MODE_RICH_TO_HTML,
+                )
 
                 o[lang] = {
                     'subject': _('Subject: {subject}'.format(subject=preview_subject)),

src/pretix/static/pretixcontrol/scss/_forms.scss

@@ -194,66 +194,6 @@ div[data-formset-body], div[data-formset-form], div[data-nested-formset-form], d
   line-height: 30px;
 }
 
-div.mail-preview {
-  border: 1px solid #ccc;
-  border-top-width: 1px;
-  border-radius: 3px;
-
-  .placeholder {
-    background: var(--pretix-brand-warning-transparent-60);
-  }
-}
-
-.mail-preview-group div[lang] {
-  @include border-top-radius(0px);
-  @include border-bottom-radius(0px);
-  border-top-width: 0;
-  margin-bottom: 0;
-  padding-right: 15px;
-  padding-bottom: 8px;
-
-  &:first-child {
-    @include border-top-radius($input-border-radius);
-    border-top-width: 1px;
-  }
-  &:last-child {
-    @include border-bottom-radius($input-border-radius);
-    margin-bottom: 20px;
-  }
-  h2, h3 {
-    margin-bottom: 20px;
-    margin-top: 10px;
-  }
-  p {
-    margin: 0 0 10px;
-
-    /* These are technically the same, but use both */
-    overflow-wrap: break-word;
-    word-wrap: break-word;
-
-    -ms-word-break: break-all;
-    /* This is the dangerous one in WebKit, as it breaks things wherever */
-    word-break: break-all;
-    /* Instead use this non-standard one: */
-    word-break: break-word;
-
-    /* Adds a hyphen where the word breaks, if supported (No Blink) */
-    -ms-hyphens: auto;
-    -moz-hyphens: auto;
-    -webkit-hyphens: auto;
-    hyphens: auto;
-  }
-  p:last-child {
-    margin-bottom: 0;
-  }
-  /* Reset styling from bootstrap that we don't actually have in emails */
-  pre {
-    background: none;
-    border: none;
-    padding: 0;
-  }
-}
-
 .search-line {
   width: 100%;
   margin-bottom: 20px;

src/pretix/static/pretixcontrol/scss/_mail_preview.scss

@@ -0,0 +1,93 @@
+div.mail-preview {
+  border: 1px solid #ccc;
+  border-top-width: 1px;
+  border-radius: 3px;
+
+  .placeholder {
+    background: var(--pretix-brand-warning-transparent-60);
+  }
+  .placeholder-html {
+    background: none;
+    outline: 2px solid var(--pretix-brand-warning-transparent-60);
+    display: inline-block;
+  }
+}
+
+.mail-preview-group div[lang] {
+  @include border-top-radius(0px);
+  @include border-bottom-radius(0px);
+  border-top-width: 0;
+  margin-bottom: 0;
+  padding-right: 15px;
+  padding-bottom: 8px;
+
+  &:first-child {
+    @include border-top-radius($input-border-radius);
+    border-top-width: 1px;
+  }
+  &:last-child {
+    @include border-bottom-radius($input-border-radius);
+    margin-bottom: 20px;
+  }
+  h2, h3 {
+    margin-bottom: 20px;
+    margin-top: 10px;
+  }
+  p {
+    margin: 0 0 10px;
+
+    /* These are technically the same, but use both */
+    overflow-wrap: break-word;
+    word-wrap: break-word;
+
+    -ms-word-break: break-all;
+    /* This is the dangerous one in WebKit, as it breaks things wherever */
+    word-break: break-all;
+    /* Instead use this non-standard one: */
+    word-break: break-word;
+
+    /* Adds a hyphen where the word breaks, if supported (No Blink) */
+    -ms-hyphens: auto;
+    -moz-hyphens: auto;
+    -webkit-hyphens: auto;
+    hyphens: auto;
+  }
+  p:last-child {
+    margin-bottom: 0;
+  }
+  /* Reset styling from bootstrap that we don't actually have in emails */
+  pre {
+    background: none;
+    border: none;
+    padding: 0;
+  }
+
+  /* Add some basic styling similar to our default email renderers */
+  a.button {
+    display: inline-block;
+    padding: 10px 16px;
+    font-size: 14px;
+    line-height: 1.33333;
+    border: 1px solid #cccccc;
+    border-radius: 6px;
+    -webkit-border-radius: 6px;
+    -moz-border-radius: 6px;
+    margin: 5px;
+    text-decoration: none;
+    color: var(--pretix-brand-primary);
+  }
+
+  table {
+    width: 100%;
+  }
+
+  table td {
+    vertical-align: top;
+    text-align: left;
+    padding: 0;
+  }
+
+  .text-right, table td.text-right {
+    text-align: right;
+  }
+}

src/pretix/static/pretixcontrol/scss/main.scss

@@ -12,6 +12,7 @@
 @import "_flags.scss";
 @import "_orders.scss";
 @import "_dashboard.scss";
+@import "_mail_preview.scss";
 @import "../../pretixbase/scss/webfont.scss";
 @import "../../fileupload/jquery.fileupload.scss";
 @import "../../leaflet/leaflet.scss";