fixed insecure uuid defaults

due to some unexpected behavior the share link uuid values were not random. All already created share links were disabled.

cookbook/migrations/0056_auto_20200625_2157.py

@@ -0,0 +1,25 @@
+# Generated by Django 3.0.7 on 2020-06-25 19:57
+
+from django.db import migrations, models
+import uuid
+
+
+def invalidate_shares(apps, schema_editor):
+    ShareLink = apps.get_model('cookbook', 'ShareLink')
+
+    ShareLink.objects.all().delete()
+
+
+class Migration(migrations.Migration):
+    dependencies = [
+        ('cookbook', '0055_auto_20200616_1236'),
+    ]
+
+    operations = [
+        migrations.AlterField(
+            model_name='sharelink',
+            name='uuid',
+            field=models.UUIDField(default=uuid.uuid4),
+        ),
+        migrations.RunPython(invalidate_shares)
+    ]

cookbook/models.py

@@ -247,7 +247,7 @@ class MealPlan(models.Model):
 
 class ShareLink(models.Model):
     recipe = models.ForeignKey(Recipe, on_delete=models.CASCADE)
-    uuid = models.UUIDField(default=uuid.uuid4())
+    uuid = models.UUIDField(default=uuid.uuid4)
     created_by = models.ForeignKey(User, on_delete=models.CASCADE)
     created_at = models.DateTimeField(auto_now_add=True)