add new signal so reports can render just where event dashboard is

doc/development/api/general.rst

@@ -83,7 +83,7 @@ Dashboards
 
 .. automodule:: pretix.control.signals
    :no-index:
-   :members: event_dashboard_widgets, user_dashboard_widgets, event_dashboard_top
+   :members: event_dashboard_widgets, event_dashboard_widgets_override, user_dashboard_widgets, event_dashboard_top
 
 Ticket designs
 """"""""""""""

src/pretix/control/signals.py

@@ -149,6 +149,31 @@ should return a list of dictionaries, where each dictionary can have the keys:
 
 As with all event plugin signals, the ``sender`` keyword argument will contain the event.
 An additional keyword argument ``subevent`` *can* contain a sub-event.
+
+The keyword argument ``widgets_override_active`` is set to ``True`` when a plugin
+has returned content from :py:data:`event_dashboard_widgets_override` and is taking
+over the KPI section of the dashboard. Receivers that produce widgets which would
+be redundant with such a replacement (e.g. the built-in attendees/revenue/products
+KPI tiles) should return an empty list in that case. Receivers that provide widgets
+unrelated to the KPI tiles (waitinglist, quotas, check-in lists, shop state, etc.)
+should ignore the flag and continue to return their widgets — those will render
+below the override block.
+"""
+
+event_dashboard_widgets_override = EventPluginSignal()
+"""
+This signal allows a plugin to take over the KPI section of the event dashboard
+with custom HTML. Receivers should return an HTML string (or an empty string /
+``None`` to opt out). If any receiver returns non-empty HTML, that HTML is
+rendered at the top of the dashboard, and receivers of
+:py:data:`event_dashboard_widgets` are informed via the
+``widgets_override_active=True`` keyword argument so they can suppress widgets
+that the override replaces. The remaining widgets (those that don't opt out)
+still render below the override block. Multiple receivers' return values are
+concatenated.
+
+As with all event plugin signals, the ``sender`` keyword argument will contain
+the event. An additional keyword argument ``subevent`` *can* contain a sub-event.
 """
 
 user_dashboard_widgets = GlobalSignal()

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

@@ -43,37 +43,42 @@
     {% if not request.event.has_subevents or subevent %}
         {% include "pretixcontrol/event/fragment_timeline.html" %}
     {% endif %}
-    <div class="dashboard">
-        {% for w in widgets %}
-            <div class="widget-container widget-{{ w.display_size|default:"small" }} {% if w.lazy %}widget-lazy-loading{% endif %}" data-lazy-id="{{ w.lazy }}">
-                {% if w.url %}{# backwards compatibility #}
-                    <a href="{{ w.url }}" class="widget">
-                        {% if w.lazy %}
-                            <span class="fa fa-cog fa-4x"></span>
-                        {% else %}
-                            {{ w.content }}
-                        {% endif %}
-                    </a>
-                {% elif w.link %}
-                    <a href="{{ w.link }}" class="widget">
-                        {% if w.lazy %}
-                            <span class="fa fa-cog fa-4x´"></span>
-                        {% else %}
-                            {{ w.content }}
-                        {% endif %}
-                    </a>
-                {% else %}
-                    <div class="widget">
-                        {% if w.lazy %}
-                            <span class="fa fa-cog fa-4x"></span>
-                        {% else %}
-                            {{ w.content }}
-                        {% endif %}
-                    </div>
-                {% endif %}
-            </div>
-        {% endfor %}
-    </div>
+    {% if widgets_override %}
+        {{ widgets_override|safe }}
+    {% endif %}
+    {% if widgets %}
+        <div class="dashboard">
+            {% for w in widgets %}
+                <div class="widget-container widget-{{ w.display_size|default:"small" }} {% if w.lazy %}widget-lazy-loading{% endif %}" data-lazy-id="{{ w.lazy }}">
+                    {% if w.url %}{# backwards compatibility #}
+                        <a href="{{ w.url }}" class="widget">
+                            {% if w.lazy %}
+                                <span class="fa fa-cog fa-4x"></span>
+                            {% else %}
+                                {{ w.content }}
+                            {% endif %}
+                        </a>
+                    {% elif w.link %}
+                        <a href="{{ w.link }}" class="widget">
+                            {% if w.lazy %}
+                                <span class="fa fa-cog fa-4x´"></span>
+                            {% else %}
+                                {{ w.content }}
+                            {% endif %}
+                        </a>
+                    {% else %}
+                        <div class="widget">
+                            {% if w.lazy %}
+                                <span class="fa fa-cog fa-4x"></span>
+                            {% else %}
+                                {{ w.content }}
+                            {% endif %}
+                        </div>
+                    {% endif %}
+                </div>
+            {% endfor %}
+        </div>
+    {% endif %}
 
     <p>&nbsp;</p>
     <div class="panel panel-default items">

src/pretix/control/views/dashboards.py

@@ -61,7 +61,8 @@ from pretix.base.models import (
 from pretix.base.services.quotas import QuotaAvailability
 from pretix.base.timeline import timeline_for_event
 from pretix.control.signals import (
-    event_dashboard_widgets, user_dashboard_widgets,
+    event_dashboard_widgets, event_dashboard_widgets_override,
+    user_dashboard_widgets,
 )
 from pretix.helpers.daterange import daterange
 
@@ -74,7 +75,9 @@ NUM_WIDGET = '<div class="numwidget"><span class="num">{num}</span><span class="
 
 
 @receiver(signal=event_dashboard_widgets)
-def base_widgets(sender, subevent=None, lazy=False, **kwargs):
+def base_widgets(sender, subevent=None, lazy=False, widgets_override_active=False, **kwargs):
+    if widgets_override_active:
+        return []
     if not lazy:
         prodc = Item.objects.filter(
             event=sender, active=True,
@@ -369,12 +372,20 @@ def event_index(request, organizer, event):
                                                                   'event.settings.general:write', request=request)
 
     widgets = []
+    widgets_override = ''
     if can_view_orders:
-        for r, result in event_dashboard_widgets.send(sender=request.event, subevent=subevent, lazy=True):
+        for r, result in event_dashboard_widgets_override.send(sender=request.event, subevent=subevent, request=request):
+            if result:
+                widgets_override += result
+        for r, result in event_dashboard_widgets.send(
+            sender=request.event, subevent=subevent, lazy=True,
+            widgets_override_active=bool(widgets_override),
+        ):
             widgets.extend(result)
 
     ctx = {
         'widgets': rearrange(widgets),
+        'widgets_override': widgets_override,
         'subevent': subevent,
         'comment_form': CommentForm(initial={'comment': request.event.comment}, readonly=not can_change_event_settings),
     }