models: add SessionIndex model (#41949)

mellon/migrations/0002_sessionindex.py

@@ -0,0 +1,28 @@
+# Generated by Django 2.2.12 on 2020-04-24 05:14
+
+from django.db import migrations, models
+import django.db.models.deletion
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('mellon', '0001_initial'),
+    ]
+
+    operations = [
+        migrations.CreateModel(
+            name='SessionIndex',
+            fields=[
+                ('id', models.AutoField(auto_created=True, primary_key=True, serialize=False, verbose_name='ID')),
+                ('session_index', models.TextField(verbose_name='SAML SessionIndex')),
+                ('session_key', models.CharField(max_length=40, verbose_name='Django session key')),
+                ('saml_identifier', models.ForeignKey(on_delete=django.db.models.deletion.CASCADE, to='mellon.UserSAMLIdentifier', verbose_name='SAML identifier')),
+            ],
+            options={
+                'verbose_name': 'SAML SessionIndex',
+                'verbose_name_plural': 'SAML SessionIndexes',
+                'unique_together': {('saml_identifier', 'session_index', 'session_key')},
+            },
+        ),
+    ]

mellon/models.py

@@ -15,6 +15,8 @@
 
 from __future__ import unicode_literals
 
+from importlib import import_module
+
 from django.db import models
 from django.utils.translation import ugettext_lazy as _
 from django.conf import settings
@@ -38,3 +40,30 @@ class UserSAMLIdentifier(models.Model):
         verbose_name = _('user SAML identifier')
         verbose_name_plural = _('users SAML identifiers')
         unique_together = (('issuer', 'name_id'),)
+
+
+class SessionIndex(models.Model):
+    session_index = models.TextField(_('SAML SessionIndex'))
+    session_key = models.CharField(_('Django session key'), max_length=40)
+    saml_identifier = models.ForeignKey(
+        verbose_name=_('SAML identifier'),
+        to=UserSAMLIdentifier,
+        on_delete=models.CASCADE)
+
+    @staticmethod
+    def cleanup(cls):
+        session_engine = import_module(settings.SESSION_ENGINE)
+        store = session_engine.SessionStore()
+
+        ids = []
+        for si in cls.objects.all():
+            if not store.exists(si.session_key):
+                ids.append(si.id)
+        cls.objects.filter(id__in=ids).delete()
+
+    class Meta:
+        verbose_name = _('SAML SessionIndex')
+        verbose_name_plural = _('SAML SessionIndexes')
+        unique_together = (
+            ('saml_identifier', 'session_index', 'session_key'),
+        )