migration for removing semantics from QueueMembership objects

helpdesk/migrations/0009_migrate_queuemembership.py

@@ -0,0 +1,56 @@
+# -*- coding: utf-8 -*-
+from __future__ import unicode_literals
+from django.db import migrations
+from django.conf import settings
+from django.utils.translation import ugettext_lazy as _
+
+
+def create_and_assign_permissions(apps, schema_editor):
+
+    # If neither Permission nor Membership mechanism are enabled, ignore the migration
+    if not ((hasattr(settings, 'HELPDESK_ENABLE_PER_QUEUE_STAFF_PERMISSION') and
+            settings.HELPDESK_ENABLE_PER_QUEUE_STAFF_PERMISSION) or
+            (hasattr(settings, 'HELPDESK_ENABLE_PER_QUEUE_STAFF_MEMBERSHIP') and
+            settings.HELPDESK_ENABLE_PER_QUEUE_STAFF_MEMBERSHIP)):
+        return
+
+    Permission = apps.get_model('auth', 'Permission')
+    ContentType = apps.get_model('contenttypes', 'ContentType')
+    # Otherwise, two steps:
+    #   1. Create the permission for existing Queues
+    #   2. Assign the permission to user according to QueueMembership objects
+
+    # First step: prepare the permission for each queue
+    Queue = apps.get_model('helpdesk', 'Queue')
+
+    for q in Queue.objects.all():
+        # Prepare the permission associated to this Queue
+        basename = "queue_access_%s" % q.slug
+        q.permission_name = "helpdesk.%s" % basename
+        Permission.objects.create(
+            name=_("Permission for queue: ") + q.title,
+            content_type=ContentType.objects.get(model="queue"),
+            codename=basename,
+        )
+        q.save()
+
+    # Second step: map the permissions according to QueueMembership
+    QueueMembership = apps.get_model('helpdesk', 'QueueMembership')
+    for qm in QueueMembership.objects.all():
+        user = qm.user
+        for q in qm.queues.all():
+            # Strip the `helpdesk.` prefix
+            p = Permission.objects.get(codename=q.permission_name[9:])
+            user.user_permissions.add(p)
+        qm.delete()
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('helpdesk', '0008_extra_for_permissions'),
+    ]
+
+    operations = [
+        migrations.RunPython(create_and_assign_permissions)
+    ]