feat(generic): add export support to list views

using https://django-tables2.readthedocs.io/en/latest/pages/export.html

apis_core/generic/templates/generic/generic_list.html

@@ -3,6 +3,7 @@
 {% load crispy_forms_tags %}
 {% load generic %}
 {% load core %}
+{% load export_url from django_tables2 %}
 {% if filter %}
 
   {% block col %}
@@ -39,7 +40,16 @@
   {% block additionalcols %}
     <div class="col-8">
       <div class="card">
-        <div class="card-header">{{ table.paginator.count }} results</div>
+        <div class="card-header">{{ table.paginator.count }} results.
+        {% if view.export_formats %}
+        Download {% for format in view.export_formats %}
+        <a href="{% export_url format %}">
+            {{ format | upper}}
+        </a>
+        {% if not forloop.last %} | {% endif %}
+        {% endfor %}
+        {% endif %}
+        </div>
         <div class="card-body">
 
           {% block table %}

apis_core/generic/views.py

@@ -1,5 +1,6 @@
 from collections import namedtuple
 from copy import copy
+from datetime import datetime
 
 from dal import autocomplete
 from django import forms, http
@@ -21,6 +22,7 @@
 from django_filters.views import FilterView
 from django_tables2 import SingleTableMixin
 from django_tables2.columns import library
+from django_tables2.export.views import ExportMixin
 from django_tables2.tables import table_factory
 
 from apis_core.apis_metainfo.models import Uri
@@ -100,6 +102,7 @@ def get_permission_required(self):
 class List(
     GenericModelMixin,
     PermissionRequiredMixin,
+    ExportMixin,
     SingleTableMixin,
     FilterView,
 ):
@@ -123,6 +126,17 @@ def get_table_class(self):
         table_class = first_member_match(table_modules, GenericTable)
         return table_factory(self.model, table_class)
 
+    export_formats = ["csv", "json"]
+
+    def get_export_filename(self, extension):
+        table_class = self.get_table_class()
+        if hasattr(table_class, "export_filename"):
+            filename = table_class.export_filename
+        else:
+            now = datetime.now()
+            filename = f"{table_class.__name__}_{now.strftime('%Y-%m-%d_%H-%M-%S')}"
+        return f"{filename}.{extension}"
+
     def get_table_kwargs(self):
         kwargs = super().get_table_kwargs()