Add a plugin API for ticket outputs

doc/development/api/index.rst

@@ -9,4 +9,5 @@ Contents:
    plugins
    restriction
    payment
+   ticketoutput
    general

doc/development/api/payment.rst

@@ -20,11 +20,10 @@ that we'll soon create::
 
     from pretix.base.signals import register_payment_providers
 
-    from .payment import Paypal
-
 
     @receiver(register_payment_providers)
     def register_payment_provider(sender, **kwargs):
+        from .payment import Paypal
         return Paypal
 
 

doc/development/api/ticketoutput.rst

@@ -0,0 +1,70 @@
+.. highlight:: python
+   :linenothreshold: 5
+
+Writing a ticket output plugin
+==============================
+
+A ticket output is a method to offer a ticket (an order) for the user to download.
+
+In this document, we will walk through the creation of a ticket output plugin. This
+is very similar to creating a payment provider.
+
+Please read :ref:`Creating a plugin <pluginsetup>` first, if you haven't already.
+
+Output registration
+-------------------
+
+The payment provider API does not make a lot of usage from signals, however, it
+does use a signal to get a list of all available ticket outputs. Your plugin
+should listen for this signal and return the subclass of ``pretix.base.ticketoutput.BaseTicketOutput``
+that we'll soon create::
+
+    from django.dispatch import receiver
+
+    from pretix.base.signals import register_ticket_outputs
+
+
+    @receiver(register_ticket_outputs)
+    def register_ticket_output(sender, **kwargs):
+        from .ticketoutput import PdfTicketOutput
+        return PdfTicketOutput
+
+
+The output class
+----------------
+
+.. class:: pretix.base.ticketoutput.BaseTicketOutput
+
+   The central object of each ticket output is the subclass of ``BaseTicketOutput``
+   we already mentioned above. In this section, we will discuss it's interface in detail.
+
+   .. py:attribute:: BaseTicketOutput.event
+
+      The default constructor sets this property to the event we are currently
+      working for.
+
+   .. py:attribute:: BaseTicketOutput.settings
+
+      The default constructor sets this property to a ``SettingsSandbox`` object. You can
+      use this object to store settings using its ``get`` and ``set`` methods. All settings
+      you store are transparently prefixed, so you get your very own settings namespace.
+
+   .. autoattribute:: identifier
+
+      This is an abstract attribute, you **must** override this!
+
+   .. autoattribute:: verbose_name
+
+      This is an abstract attribute, you **must** override this!
+
+   .. autoattribute:: is_enabled
+
+   .. autoattribute:: settings_form_fields
+
+   .. automethod:: settings_content_render
+
+   .. automethod:: generate
+
+   .. autoattribute:: download_button_text
+
+   .. autoattribute:: download_button_icon

src/pretix/base/payment.py

@@ -123,6 +123,7 @@ class BasePaymentProvider:
         page, this method is called. It may return HTML containing additional information
         that is displayed below the form fields configured in ``settings_form_fields``.
         """
+        pass
 
     @property
     def checkout_form_fields(self) -> dict:

src/pretix/base/signals.py

@@ -60,3 +60,11 @@ subclass of pretix.base.payment.BasePaymentProvider
 register_payment_providers = EventPluginSignal(
     providing_args=[]
 )
+
+"""
+This signal is sent out to get all known ticket outputs. Receivers should return a
+subclass of pretix.base.ticketoutput.BaseTicketOutput
+"""
+register_ticket_outputs = EventPluginSignal(
+    providing_args=[]
+)

src/pretix/base/ticketoutput.py

@@ -0,0 +1,116 @@
+from collections import OrderedDict
+from django import forms
+
+from django.http import HttpRequest, HttpResponse
+from django.utils.translation import ugettext_lazy as _
+from pretix.base.forms import SettingsForm
+from pretix.base.models import Order
+
+from pretix.base.settings import SettingsSandbox
+
+
+class BaseTicketOutput:
+    """
+    This is the base class for all ticket outputs.
+    """
+
+    def __init__(self, event):
+        self.event = event
+        self.settings = SettingsSandbox('ticketoutput', self.identifier, event)
+
+    def __str__(self):
+        return self.identifier
+
+    @property
+    def is_enabled(self) -> bool:
+        """
+        Returns, whether or whether not this output is enabled.
+        By default, this is determined by the value of the ``_enabled`` setting.
+        """
+        return self.settings.get('_enabled', as_type=bool)
+
+    def generate(self, request: HttpRequest, order: Order) -> HttpResponse:
+        """
+        This method should generate the download file and return it to the user.
+        """
+        raise NotImplementedError()
+
+    @property
+    def verbose_name(self) -> str:
+        """
+        A human-readable name for this ticket output. This should
+        be short but self-explaining. Good examples include 'PDF tickets'
+        and 'Passbook'.
+        """
+        raise NotImplementedError()  # NOQA
+
+    @property
+    def identifier(self) -> str:
+        """
+        A short and unique identifier for this ticket output.
+        This should only contain lowercase letters and in most
+        cases will be the same as your packagename.
+        """
+        raise NotImplementedError()  # NOQA
+
+    @property
+    def settings_form_fields(self) -> dict:
+        """
+        When the event's administrator administrator visits the event configuration
+        page, this method is called to return the configuration fields available.
+
+        It should therefore return a dictionary where the keys should be (unprefixed)
+        settings keys and the values should be corresponding Django form fields.
+
+        The default implementation returns the appropriate fields for the ``_enabled``
+        setting mentioned above.
+
+        We suggest that you return an ``OrderedDict`` object instead of a dictionary
+        and make use of the default implementation. Your implementation could look
+        like this::
+
+            @property
+            def settings_form_fields(self):
+                return OrderedDict(
+                    list(super().settings_form_fields.items()) + [
+                        ('paper_size',
+                         forms.CharField(
+                             label=_('Paper size'),
+                             required=False
+                         ))
+                    ]
+                )
+
+        .. WARNING:: It is highly discouraged to alter the ``_enabled`` field of the default
+                     implementation.
+        """
+        return OrderedDict([
+            ('_enabled',
+             forms.ChoiceField(
+                 label=_('Enable output'),
+                 required=False,
+                 choices=SettingsForm.BOOL_CHOICES,
+             )),
+        ])
+
+    def settings_content_render(self, request: HttpRequest) -> str:
+        """
+        When the event's administrator administrator visits the event configuration
+        page, this method is called. It may return HTML containing additional information
+        that is displayed below the form fields configured in ``settings_form_fields``.
+        """
+        pass
+
+    @property
+    def download_button_text(self) -> str:
+        """
+        The text on the download button in the frontend.
+        """
+        return _('Download ticket')
+
+    @property
+    def download_button_icon(self) -> str:
+        """
+        The name of the icon on the download button in the frontend
+        """
+        return None

src/pretix/control/templates/pretixcontrol/event/tickets.html

@@ -13,6 +13,27 @@
             <legend>{% trans "Ticket download" %}</legend>
             {% bootstrap_field form.ticket_download layout="horizontal" %}
             {% bootstrap_field form.ticket_download_date layout="horizontal" %}
+            {% for provider in providers %}
+                <div class="panel panel-default">
+                    <div class="panel-heading">
+                        <div class="row">
+                            <div class="col-sm-10">
+                                <h3 class="panel-title">{{ provider.verbose_name }}</h3>
+                            </div>
+                        </div>
+                    </div>
+                    <div class="panel-body">
+                        {%  bootstrap_form provider.form layout='horizontal' %}
+                        {% with c=provider.settings_content %}
+                            {% if c %}{{ c|safe }}{% endif %}
+                        {% endwith %}
+                    </div>
+                </div>
+            {% empty %}
+                <div class="alert alert-warning">
+                    {% trans "There are no ticket outputs available. Please go to the plugin settings and activate one or more ticket output plugins." %}</em>
+                </div>
+            {% endfor %}
         </fieldset>
         <div class="form-group submit-group">
             <button type="submit" class="btn btn-primary btn-save">

src/pretix/control/views/event.py

@@ -13,7 +13,7 @@ from pytz import common_timezones
 
 from pretix.base.forms import VersionedModelForm, SettingsForm
 from pretix.base.models import Event
-from pretix.base.signals import register_payment_providers
+from pretix.base.signals import register_payment_providers, register_ticket_outputs
 from pretix.control.permissions import EventPermissionRequiredMixin
 from . import UpdateView
 
@@ -215,7 +215,7 @@ class EventPlugins(EventPermissionRequiredMixin, TemplateView, SingleObjectMixin
         }) + '?success=true'
 
 
-class PaymentMethodForm(SettingsForm):
+class ProviderForm(SettingsForm):
     """
     This is a SettingsForm, but if fields are set to required=True, validation
     errors are only raised if the payment method is enabled.
@@ -258,7 +258,7 @@ class PaymentSettings(EventPermissionRequiredMixin, TemplateView, SingleObjectMi
         responses = register_payment_providers.send(self.request.event)
         for receiver, response in responses:
             provider = response(self.request.event)
-            provider.form = PaymentMethodForm(
+            provider.form = ProviderForm(
                 obj=self.request.event,
                 settingspref='payment_%s_' % provider.identifier,
                 data=(self.request.POST if self.request.method == 'POST' else None)
@@ -346,6 +346,11 @@ class TicketSettings(EventPermissionRequiredMixin, FormView):
         form.save()
         return super().form_valid(form)
 
+    def get_context_data(self, *args, **kwargs) -> dict:
+        context = super().get_context_data(*args, **kwargs)
+        context['providers'] = self.provider_forms
+        return context
+
     def get_success_url(self) -> str:
         return reverse('control:event.settings.tickets', kwargs={
             'organizer': self.request.event.organizer.slug,
@@ -362,6 +367,41 @@ class TicketSettings(EventPermissionRequiredMixin, FormView):
         form.prepare_fields()
         return form
 
+    def post(self, request, *args, **kwargs):
+        success = True
+        for provider in self.provider_forms:
+            if provider.form.is_valid():
+                provider.form.save()
+            else:
+                success = False
+        form = self.get_form(self.get_form_class())
+        if success and form.is_valid():
+            return redirect(self.get_success_url())
+        else:
+            return self.get(request)
+
+    @cached_property
+    def provider_forms(self) -> list:
+        providers = []
+        responses = register_ticket_outputs.send(self.request.event)
+        for receiver, response in responses:
+            provider = response(self.request.event)
+            provider.form = ProviderForm(
+                obj=self.request.event,
+                settingspref='ticketoutput_%s_' % provider.identifier,
+                data=(self.request.POST if self.request.method == 'POST' else None)
+            )
+            provider.form.fields = OrderedDict(
+                [
+                    ('ticketoutput_%s_%s' % (provider.identifier, k), v)
+                    for k, v in provider.settings_form_fields.items()
+                ]
+            )
+            provider.settings_content = provider.settings_content_render(self.request)
+            provider.form.prepare_fields()
+            providers.append(provider)
+        return providers
+
 
 def index(request, organizer, event):
     return render(request, 'pretixcontrol/event/index.html', {})

src/pretix/plugins/ticketoutputpdf/__init__.py

@@ -0,0 +1,30 @@
+from django.apps import AppConfig
+from django.utils.functional import cached_property
+from django.utils.translation import ugettext_lazy as _
+from pretix.base.plugins import PluginType
+
+
+class TicketOutputPdfApp(AppConfig):
+    name = 'pretix.plugins.ticketoutputpdf'
+    verbose_name = _("PDF ticket output")
+
+    class PretixPluginMeta:
+        type = PluginType.PAYMENT
+        name = _("PDF ticket output")
+        author = _("the pretix team")
+        version = '1.0.0'
+        description = _("This plugin allows you to print out tickets as PDF files")
+
+    def ready(self):
+        from . import signals  # NOQA
+
+    @cached_property
+    def compatibility_errors(self):
+        errs = []
+        try:
+            import reportlab
+        except ImportError:
+            errs.append("Python package 'reportlab' is not installed.")
+        return errs
+
+default_app_config = 'pretix.plugins.ticketoutputpdf.TicketOutputPdfApp'

src/pretix/plugins/ticketoutputpdf/signals.py

@@ -0,0 +1,9 @@
+from django.dispatch import receiver
+
+from pretix.base.signals import register_ticket_outputs
+
+
+@receiver(register_ticket_outputs)
+def register_ticket_outputs(sender, **kwargs):
+    from .ticketoutput import PdfTicketOutput
+    return PdfTicketOutput

src/pretix/plugins/ticketoutputpdf/ticketoutput.py

@@ -0,0 +1,86 @@
+from io import BytesIO
+import logging
+from django.contrib import messages
+from django.contrib.staticfiles import finders
+from django.http import HttpResponse
+from django.shortcuts import redirect
+from django.utils.timezone import now
+from django.utils.translation import ugettext_lazy as _
+from pretix.base.models import Order
+
+from pretix.base.ticketoutput import BaseTicketOutput
+
+
+logger = logging.getLogger('pretix.plugins.ticketoutputpdf')
+
+
+class PdfTicketOutput(BaseTicketOutput):
+
+    identifier = 'pdf'
+    verbose_name = _('PDF output')
+    download_button_text = _('Download PDF')
+    download_button_icon = 'fa-print'
+
+    def generate(self, request, order):
+        from reportlab.graphics.shapes import Drawing
+        from reportlab.pdfgen import canvas
+        from reportlab.lib import pagesizes, units
+        from reportlab.graphics.barcode.qr import QrCodeWidget
+        from reportlab.graphics import renderPDF
+        from PyPDF2 import PdfFileWriter, PdfFileReader
+
+        response = HttpResponse(content_type='application/pdf')
+        response['Content-Disposition'] = 'inline; filename="order%s%s.pdf"' % (request.event.slug, order.code)
+
+        pagesize = request.event.settings.get('ticketpdf_pagesize', default='A4')
+        if hasattr(pagesizes, pagesize):
+            pagesize = getattr(pagesizes, pagesize)
+        else:
+            pagesize = pagesizes.A4
+        defaultfname = finders.find('pretixpresale/pdf/ticket_default_a4.pdf')
+        fname = request.event.settings.get('ticketpdf_background', default=defaultfname)
+        # TODO: Handle file objects
+
+        buffer = BytesIO()
+        p = canvas.Canvas(buffer, pagesize=pagesize)
+
+        for op in order.positions.all().select_related('item', 'variation'):
+            p.setFont("Helvetica", 22)
+            p.drawString(15 * units.mm, 235 * units.mm, str(request.event.name))
+
+            p.setFont("Helvetica", 17)
+            item = str(op.item.name)
+            if op.variation:
+                item += " – " + str(op.variation)
+            p.drawString(15 * units.mm, 220 * units.mm, item)
+
+            p.setFont("Helvetica", 17)
+            p.drawString(15 * units.mm, 210 * units.mm, "%s %s" % (str(op.price), request.event.currency))
+
+            reqs = 80 * units.mm
+            qrw = QrCodeWidget(op.identity, barLevel='H')
+            b = qrw.getBounds()
+            w = b[2] - b[0]
+            h = b[3] - b[1]
+            d = Drawing(reqs, reqs, transform=[reqs / w, 0, 0, reqs / h, 0, 0])
+            d.add(qrw)
+            renderPDF.draw(d, p, 10 * units.mm, 130 * units.mm)
+
+            p.setFont("Helvetica", 11)
+            p.drawString(15 * units.mm, 130 * units.mm, op.identity)
+
+            p.showPage()
+
+        p.save()
+
+        buffer.seek(0)
+        new_pdf = PdfFileReader(buffer)
+        output = PdfFileWriter()
+        for page in new_pdf.pages:
+            bg_pdf = PdfFileReader(open(fname, "rb"))
+            bg_page = bg_pdf.getPage(0)
+            bg_page.mergePage(page)
+            output.addPage(bg_page)
+
+        output.write(response)
+        return response

src/pretix/presale/templates/pretixpresale/event/order.html

@@ -37,10 +37,12 @@
                             entering the event.
                         {% endblocktrans %}
                     </p>
-                    <a href="{% url "presale:event.order.download" organizer=request.event.organizer.slug event=request.event.slug order=order.code %}"
+                    {% for b in download_buttons %}
-                            class="btn btn-primary">
+                        <a href="{% url "presale:event.order.download" organizer=request.event.organizer.slug event=request.event.slug order=order.code output=b.identifier %}"
-                        <span class="fa fa-print"></span> {% trans "Download PDF" %}
+                                class="btn btn-primary">
-                    </a>
+                            <span class="fa {{ b.icon }}"></span> {{ b.text }}
+                        </a>
+                    {% endfor %}
                 {% else %}
                     {% blocktrans trimmed with date=event.settings.ticket_download_date|date %}
                         You will be able to download your tickets here on {{ date }}.

src/pretix/presale/urls.py

@@ -22,7 +22,7 @@ urlpatterns = [
             name='event.order.cancel'),
         url(r'^order/(?P<order>[^/]+)/modify$', pretix.presale.views.order.OrderModify.as_view(),
             name='event.order.modify'),
-        url(r'^order/(?P<order>[^/]+)/download$', pretix.presale.views.order.OrderDownload.as_view(),
+        url(r'^order/(?P<order>[^/]+)/download/(?P<output>[^/]+)$', pretix.presale.views.order.OrderDownload.as_view(),
             name='event.order.download'),
         url(r'^login$', pretix.presale.views.event.EventLogin.as_view(), name='event.checkout.login'),
         url(r'^logout$', pretix.presale.views.event.EventLogout.as_view(), name='event.logout'),

src/pretix/presale/views/order.py

@@ -8,7 +8,7 @@ from django.utils.functional import cached_property
 from django.views.generic import TemplateView, View
 from django.http import HttpResponseNotFound, HttpResponseForbidden, HttpResponse
 from pretix.base.models import Order, OrderPosition
-from pretix.base.signals import register_payment_providers
+from pretix.base.signals import register_payment_providers, register_ticket_outputs
 from pretix.presale.views import EventViewMixin, EventLoginRequiredMixin, CartDisplayMixin
 from pretix.presale.views.checkout import QuestionsViewMixin
 from django.contrib.staticfiles import finders
@@ -46,6 +46,21 @@ class OrderDetails(EventViewMixin, EventLoginRequiredMixin, OrderDetailMixin,
             if provider.identifier == self.order.payment_provider:
                 return provider
 
+    @cached_property
+    def download_buttons(self):
+        buttons = []
+        responses = register_ticket_outputs.send(self.request.event)
+        for receiver, response in responses:
+            provider = response(self.request.event)
+            if not provider.is_enabled:
+                continue
+            buttons.append({
+                'icon': provider.download_button_icon or 'fa-download',
+                'text': provider.download_button_text or 'fa-download',
+                'identifier': provider.identifier,
+            })
+        return buttons
+
     def get_context_data(self, **kwargs):
         ctx = super().get_context_data(**kwargs)
         ctx['order'] = self.order
@@ -54,6 +69,7 @@ class OrderDetails(EventViewMixin, EventLoginRequiredMixin, OrderDetailMixin,
             and now() > self.request.event.settings.ticket_download_date
             and self.order.status == Order.STATUS_PAID
         )
+        ctx['download_buttons'] = self.download_buttons
         ctx['cart'] = self.get_cart(
             answers=True,
             queryset=OrderPosition.objects.current.filter(order=self.order)
@@ -157,73 +173,22 @@ class OrderDownload(EventViewMixin, EventLoginRequiredMixin, OrderDetailMixin,
             'order': self.order.code,
         })
 
-    def get(self, request, *args, **kwargs):
+    @cached_property
-        from reportlab.graphics.shapes import Drawing
+    def output(self):
-        from reportlab.pdfgen import canvas
+        responses = register_ticket_outputs.send(self.request.event)
-        from reportlab.lib import pagesizes, units
+        for receiver, response in responses:
-        from reportlab.graphics.barcode.qr import QrCodeWidget
+            provider = response(self.request.event)
-        from reportlab.graphics import renderPDF
+            if provider.identifier == self.kwargs.get('output'):
-        from PyPDF2 import PdfFileWriter, PdfFileReader
+                return provider
 
+    def get(self, request, *args, **kwargs):
+        if not self.output or not self.output.is_enabled:
+            messages.error(request, _('You requested an invalid ticket output type.'))
+            return redirect(self.get_order_url())
         if self.order.status != Order.STATUS_PAID:
             messages.error(request, _('Order is not paid.'))
             return redirect(self.get_order_url())
         if not self.request.event.settings.ticket_download or now() < self.request.event.settings.ticket_download_date:
             messages.error(request, _('Ticket download is not (yet) enabled.'))
             return redirect(self.get_order_url())
-
+        return self.output.generate(request, self.order)
-        response = HttpResponse(content_type='application/pdf')
-        response['Content-Disposition'] = 'inline; filename="order%s%s.pdf"' % (request.event.slug, self.order.code)
-
-        pagesize = request.event.settings.get('ticketpdf_pagesize', default='A4')
-        if hasattr(pagesizes, pagesize):
-            pagesize = getattr(pagesizes, pagesize)
-        else:
-            pagesize = pagesizes.A4
-        defaultfname = finders.find('pretixpresale/pdf/ticket_default_a4.pdf')
-        fname = request.event.settings.get('ticketpdf_background', default=defaultfname)
-        # TODO: Handle file objects
-
-        buffer = BytesIO()
-        p = canvas.Canvas(buffer, pagesize=pagesize)
-
-        for op in self.order.positions.all().select_related('item', 'variation'):
-            p.setFont("Helvetica", 22)
-            p.drawString(15 * units.mm, 235 * units.mm, str(request.event.name))
-
-            p.setFont("Helvetica", 17)
-            item = str(op.item.name)
-            if op.variation:
-                item += " – " + str(op.variation)
-            p.drawString(15 * units.mm, 220 * units.mm, item)
-
-            p.setFont("Helvetica", 17)
-            p.drawString(15 * units.mm, 210 * units.mm, "%s %s" % (str(op.price), request.event.currency))
-
-            reqs = 80 * units.mm
-            qrw = QrCodeWidget(op.identity, barLevel='H')
-            b = qrw.getBounds()
-            w = b[2] - b[0]
-            h = b[3] - b[1]
-            d = Drawing(reqs, reqs, transform=[reqs / w, 0, 0, reqs / h, 0, 0])
-            d.add(qrw)
-            renderPDF.draw(d, p, 10 * units.mm, 130 * units.mm)
-
-            p.setFont("Helvetica", 11)
-            p.drawString(15 * units.mm, 130 * units.mm, op.identity)
-
-            p.showPage()
-
-        p.save()
-
-        buffer.seek(0)
-        new_pdf = PdfFileReader(buffer)
-        output = PdfFileWriter()
-        for page in new_pdf.pages:
-            bg_pdf = PdfFileReader(open(fname, "rb"))
-            bg_page = bg_pdf.getPage(0)
-            bg_page.mergePage(page)
-            output.addPage(bg_page)
-
-        output.write(response)
-        return response

src/pretix/settings.py

@@ -49,6 +49,7 @@ INSTALLED_APPS = (
     'pretix.plugins.banktransfer',
     'pretix.plugins.stripe',
     'pretix.plugins.paypal',
+    'pretix.plugins.ticketoutputpdf',
 )
 
 MIDDLEWARE_CLASSES = (