Make available languages configurable

src/pretix/base/forms.py

@@ -1,11 +1,25 @@
 from django.forms.models import ModelFormMetaclass, BaseModelForm
 from django import forms
 from django.utils import six
+from pretix.base.i18n import I18nFormField
 from versions.models import Versionable
 from django.utils.translation import ugettext_lazy as _
 
 
-class VersionedBaseModelForm(BaseModelForm):
+class BaseI18nModelForm(BaseModelForm):
+    """
+    This is a helperclass to construct I18nModelForm
+    """
+    def __init__(self, *args, **kwargs):
+        event = kwargs.pop('event', None)
+        super().__init__(*args, **kwargs)
+        if event:
+            for k, field in self.fields.items():
+                if isinstance(field, I18nFormField):
+                    field.widget.enabled_langcodes = event.settings.get('locales')
+
+
+class VersionedBaseModelForm(BaseI18nModelForm):
     """
     This is a helperclass to construct VersionedModelForm
     """
@@ -18,7 +32,7 @@ class VersionedBaseModelForm(BaseModelForm):
 
 class VersionedModelForm(six.with_metaclass(ModelFormMetaclass, VersionedBaseModelForm)):
     """
-    This is a modified version of Django's ModelForm which differs from ModelForm in
+    This is a modified version of I18nModelForm which differs from I18nModelForm in
     only one way: It executes the .clone() method of an object before saving it back to
     the database, if the model is a sub-class of versions.models.Versionable. You can
     safely use this as a base class for all your model forms, it will work out correctly
@@ -27,6 +41,17 @@ class VersionedModelForm(six.with_metaclass(ModelFormMetaclass, VersionedBaseMod
     pass
 
 
+class I18nModelForm(six.with_metaclass(ModelFormMetaclass, BaseI18nModelForm)):
+    """
+    This is a modified version of Django's ModelForm which differs from ModelForm in
+    only one way: The constructor takes one additional optional argument ``event``
+    which may be given an :pyclass:`pretix.base.models.Event` instance. If given, this
+    instance is used to select the visible languages in all I18nFormFields of the form. If
+    not given, all languages will be displayed.
+    """
+    pass
+
+
 class SettingsForm(forms.Form):
     """
     This form is meant to be used for modifying Event- or OrganizerSettings

src/pretix/base/i18n.py

@@ -4,10 +4,18 @@ from django.conf import settings
 from django.db.models import TextField, SubfieldBase
 from django import forms
 from django.utils import translation
+from django.utils.safestring import mark_safe
 
 
-class LazyI18String:
+class LazyI18nString:
+    """
+    This represents an internationalized string that is/was/will be stored in the database.
+    """
+
     def __init__(self, data):
+        """
+        Input data should be a dictionary which maps language codes to content.
+        """
         self.data = data
         if isinstance(self.data, str) and self.data is not None:
             try:
@@ -18,6 +26,11 @@ class LazyI18String:
                 self.data = j
 
     def __str__(self):
+        """
+        Evaluate the given string with respect to the currently active locale.
+        This will rather return you a string in a wrong language than give you an
+        empty value.
+        """
         if self.data is None:
             return ""
         if isinstance(self.data, dict):
@@ -41,14 +54,19 @@ class LazyI18String:
 
 
 class I18nWidget(forms.MultiWidget):
+    """
+    The default form widget for I18nCharField and I18nTextField. It makes
+    use of Django's MultiWidget mechanism and does some magic to save you
+    time.
+    """
     widget = forms.TextInput
 
-    def langcodes(self):
+    def __init__(self, langcodes, field, attrs=None):
-        return [l[0] for l in settings.LANGUAGES]
-
-    def __init__(self, attrs=None):
         widgets = []
-        for lng in self.langcodes():
+        self.langcodes = langcodes
+        self.enabled_langcodes = langcodes
+        self.field = field
+        for lng in self.langcodes:
             a = copy.copy(attrs) or {}
             a['data-lang'] = lng
             widgets.append(self.widget(attrs=a))
@@ -56,7 +74,7 @@ class I18nWidget(forms.MultiWidget):
 
     def decompress(self, value):
         data = []
-        for lng in self.langcodes():
+        for lng in self.langcodes:
             data.append(
                 value.data[lng]
                 if value is not None and isinstance(value.data, dict) and lng in value.data
@@ -66,6 +84,29 @@ class I18nWidget(forms.MultiWidget):
             data[0] = value.data
         return data
 
+    def render(self, name, value, attrs=None):
+        if self.is_localized:
+            for widget in self.widgets:
+                widget.is_localized = self.is_localized
+        # value is a list of values, each corresponding to a widget
+        # in self.widgets.
+        if not isinstance(value, list):
+            value = self.decompress(value)
+        output = []
+        final_attrs = self.build_attrs(attrs)
+        id_ = final_attrs.get('id', None)
+        for i, widget in enumerate(self.widgets):
+            if self.langcodes[i] not in self.enabled_langcodes:
+                continue
+            try:
+                widget_value = value[i]
+            except IndexError:
+                widget_value = None
+            if id_:
+                final_attrs = dict(final_attrs, id='%s_%s' % (id_, i))
+            output.append(widget.render(name + '_%s' % i, widget_value, final_attrs))
+        return mark_safe(self.format_output(output))
+
     def format_output(self, rendered_widgets):
         return '<div class="i18n-form-group">%s</div>' % super().format_output(rendered_widgets)
 
@@ -79,16 +120,18 @@ class I18nTextarea(I18nWidget):
 
 
 class I18nFormField(forms.MultiValueField):
+    """
+    The form field that is used by I18nCharField and I18nTextField. It makes use
+    of Django's MultiValueField mechanism to create one sub-field per available
+    language.
+    """
 
     def compress(self, data_list):
-        langcodes = self.langcodes()
+        langcodes = self.langcodes
         data = {}
         for i, value in enumerate(data_list):
             data[langcodes[i]] = value
-        return LazyI18String(data)
+        return LazyI18nString(data)
-
-    def langcodes(self):
-        return [l[0] for l in settings.LANGUAGES]
 
     def clean(self, value):
         found = False
@@ -124,10 +167,14 @@ class I18nFormField(forms.MultiValueField):
             'widget': self.widget,
             'max_length': kwargs.pop('max_length', None),
         }
+        self.langcodes = kwargs.pop('langcodes', [l[0] for l in settings.LANGUAGES])
         self.one_required = kwargs['required']
         kwargs['required'] = False
+        kwargs['widget'] = kwargs['widget'](
+            langcodes=self.langcodes, field=self
+        )
         defaults.update(**kwargs)
-        for lngcode in self.langcodes():
+        for lngcode in self.langcodes:
             defaults['label'] = '%s (%s)' % (defaults.get('label'), lngcode)
             fields.append(forms.CharField(**defaults))
         super().__init__(
@@ -144,15 +191,15 @@ class I18nFieldMixin:
         super().__init__(*args, **kwargs)
 
     def to_python(self, value):
-        if isinstance(value, LazyI18String):
+        if isinstance(value, LazyI18nString):
             return value
-        return LazyI18String(value)
+        return LazyI18nString(value)
 
     def get_prep_value(self, value):
-        if isinstance(value, LazyI18String):
+        if isinstance(value, LazyI18nString):
             value = value.data
         if isinstance(value, dict):
-            return json.dumps(value, sort_keys=True)
+            return json.dumps({k: v for k, v in value.items() if v}, sort_keys=True)
         return value
 
     def get_prep_lookup(self, lookup_type, value):
@@ -165,8 +212,16 @@ class I18nFieldMixin:
 
 
 class I18nCharField(I18nFieldMixin, TextField, metaclass=SubfieldBase):
+    """
+    A CharField which takes internationalized data. Internally, a TextField dabase
+    field is used to store JSON. If you interact with this field, you will work
+    with LazyI18nString instances.
+    """
     widget = I18nTextInput
 
 
 class I18nTextField(I18nFieldMixin, TextField, metaclass=SubfieldBase):
+    """
+    Like I18nCharField, but for TextFields.
+    """
     widget = I18nTextarea

src/pretix/base/settings.py

@@ -41,6 +41,10 @@ DEFAULTS = {
         'default': settings.TIME_ZONE,
         'type': str
     },
+    'locales': {
+        'default': json.dumps([settings.LANGUAGE_CODE]),
+        'type': list
+    },
     'locale': {
         'default': settings.LANGUAGE_CODE,
         'type': str

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

@@ -19,6 +19,7 @@
         </fieldset>
         <fieldset>
             <legend>{% trans "Display settings" %}</legend>
+            {% bootstrap_field sform.locales layout="horizontal" %}
             {% bootstrap_field sform.locale layout="horizontal" %}
             {% bootstrap_field sform.timezone layout="horizontal" %}
             {% bootstrap_field sform.show_date_to layout="horizontal" %}

src/pretix/control/views/__init__.py

@@ -0,0 +1,28 @@
+from django.views.generic import edit
+
+
+class EventBasedFormMixin:
+
+    def get_form_kwargs(self):
+        kwargs = super().get_form_kwargs()
+        if hasattr(self.request, 'event'):
+            kwargs['event'] = self.request.event
+        return kwargs
+
+
+class CreateView(EventBasedFormMixin, edit.CreateView):
+    """
+    Like Django's default CreateView, but passes the optional event
+    argument to the form. This is necessary for I18nModelForms to work
+    properly.
+    """
+    pass
+
+
+class UpdateView(EventBasedFormMixin, edit.UpdateView):
+    """
+    Like Django's default UpdateView, but passes the optional event
+    argument to the form. This is necessary for I18nModelForms to work
+    properly.
+    """
+    pass

src/pretix/control/views/event.py

@@ -2,7 +2,6 @@ from collections import OrderedDict
 from django.conf import settings
 from django.shortcuts import render, redirect
 from django.utils.functional import cached_property
-from django.views.generic.edit import UpdateView
 from django.views.generic.base import TemplateView
 from django.views.generic.detail import SingleObjectMixin
 from django import forms
@@ -15,6 +14,7 @@ from pretix.base.forms import VersionedModelForm, SettingsForm
 from pretix.base.models import Event
 from pretix.base.signals import register_payment_providers
 from pretix.control.permissions import EventPermissionRequiredMixin
+from . import UpdateView
 
 
 class EventUpdateForm(VersionedModelForm):
@@ -71,9 +71,13 @@ class EventSettingsForm(SettingsForm):
         choices=((a, a) for a in common_timezones),
         label=_("Default timezone"),
     )
+    locales = forms.MultipleChoiceField(
+        choices=settings.LANGUAGES,
+        label=_("Available langauges"),
+    )
     locale = forms.ChoiceField(
         choices=settings.LANGUAGES,
-        label=_("Default locale"),
+        label=_("Default language"),
     )
     user_mail_required = forms.BooleanField(
         label=_("Require e-mail adresses"),

src/pretix/control/views/forms.py

@@ -3,6 +3,7 @@ from itertools import product
 from django import forms
 from django.core.exceptions import ValidationError
 from django.db import transaction
+from django.forms import BaseInlineFormSet
 from django.forms.widgets import flatatt
 from django.utils.encoding import force_text
 from django.utils.html import format_html
@@ -13,6 +14,20 @@ from pretix.base.forms import VersionedModelForm
 from pretix.base.models import ItemVariation, Item
 
 
+class I18nInlineFormSet(BaseInlineFormSet):
+    """
+    This is equivalent to a normal BaseInlineFormset, but cares for the special needs
+    of I18nForms (see there for more information).
+    """
+    def __init__(self, *args, **kwargs):
+        self.event = kwargs.pop('event', None)
+        super().__init__(*args, **kwargs)
+
+    def _construct_form(self, i, **kwargs):
+        kwargs['event'] = self.event
+        return super()._construct_form(i, **kwargs)
+
+
 class TolerantFormsetModelForm(VersionedModelForm):
     """
     This is equivalent to a normal VersionedModelForm, but works around a problem that

src/pretix/control/views/item.py

@@ -4,7 +4,7 @@ from django.forms import BooleanField, ModelForm
 from django.utils.functional import cached_property
 
 from django.views.generic import ListView
-from django.views.generic.edit import CreateView, UpdateView, DeleteView
+from django.views.generic.edit import DeleteView
 from django.views.generic.base import TemplateView
 from django.views.generic.detail import SingleObjectMixin
 from django.core.urlresolvers import resolve, reverse
@@ -12,14 +12,15 @@ from django.http import HttpResponseRedirect, HttpResponseForbidden
 from django.shortcuts import redirect
 from django.forms.models import inlineformset_factory
 from django.utils.translation import ugettext_lazy as _
-from pretix.base.forms import VersionedModelForm
+from pretix.base.forms import VersionedModelForm, I18nModelForm
 
 from pretix.base.models import (
     Item, ItemCategory, Property, ItemVariation, PropertyValue, Question, Quota,
     Versionable)
 from pretix.control.permissions import EventPermissionRequiredMixin, event_permission_required
-from pretix.control.views.forms import TolerantFormsetModelForm, VariationsField
+from pretix.control.views.forms import TolerantFormsetModelForm, VariationsField, I18nInlineFormSet
 from pretix.control.signals import restriction_formset
+from . import UpdateView, CreateView
 
 
 class ItemList(ListView):
@@ -215,6 +216,7 @@ class PropertyUpdate(EventPermissionRequiredMixin, UpdateView):
         formsetclass = inlineformset_factory(
             Property, PropertyValue,
             form=PropertyValueForm,
+            formset=I18nInlineFormSet,
             can_order=True,
             extra=0,
         )
@@ -269,6 +271,7 @@ class PropertyCreate(EventPermissionRequiredMixin, CreateView):
         formsetclass = inlineformset_factory(
             Property, PropertyValue,
             form=PropertyValueForm,
+            formset=I18nInlineFormSet,
             can_order=True,
             extra=3,
         )
@@ -440,7 +443,7 @@ class QuotaList(ListView):
         ).prefetch_related("items")
 
 
-class QuotaForm(ModelForm):
+class QuotaForm(I18nModelForm):
 
     def __init__(self, **kwargs):
         items = kwargs['items']