feature: csv export in admin

djangoldp/admin.py

+from csv import DictWriter
 from django.contrib import admin
-from guardian.admin import GuardedModelAdmin
 from django.contrib.auth.admin import UserAdmin
+from django.core.exceptions import FieldDoesNotExist
+from django.http import HttpResponse
+from guardian.admin import GuardedModelAdmin
 from djangoldp.models import Activity, ScheduledActivity, Follower
 from djangoldp.activities.services import ActivityQueueService
 
@@ -10,10 +13,33 @@ class DjangoLDPAdmin(GuardedModelAdmin):
     An admin model representing a federated object. Inherits from GuardedModelAdmin to provide Django-Guardian
     object-level permissions
     '''
-    pass
-
-
-class DjangoLDPUserAdmin(UserAdmin, GuardedModelAdmin):
+    actions = ['export_csv']
+    export_fields = []
+
+    def resolve_verbose_name(self, field_path):
+        field = self
+        for field_name in field_path.split('__'):
+            try:
+                field = field.model._meta.get_field(field_name)
+            except FieldDoesNotExist:
+                return None
+        return field.verbose_name
+
+    @admin.action(description="Export CSV")
+    def export_csv(self, request, queryset):
+        response = HttpResponse(content_type="text/csv")
+        response['Content-Disposition'] = f'attachment; filename="{self.model.__name__}.csv"'
+        # only keep fields that can be resolved, keep only urlid if none
+        field_list = list(filter(self.resolve_verbose_name, self.export_fields or self.list_display)) or ['urlid']
+        headers = {field:self.resolve_verbose_name(field) for field in field_list}
+
+        writer = DictWriter(response, fieldnames=field_list)
+        writer.writerow(headers)
+        writer.writerows(queryset.values(*field_list))
+        return response
+
+
+class DjangoLDPUserAdmin(UserAdmin, DjangoLDPAdmin):
     '''An extension of UserAdmin providing the functionality of DjangoLDPAdmin'''
 
     list_display = ('urlid', 'email', 'first_name', 'last_name', 'date_joined', 'last_login', 'is_staff')