Unify concept of absolute_id and remote_id

fedireads/models/base_model.py

@@ -1,5 +1,6 @@
 ''' base model with default fields '''
 from django.db import models
+from django.dispatch import receiver
 
 from fedireads.settings import DOMAIN
 
@@ -7,18 +8,24 @@ class FedireadsModel(models.Model):
     ''' fields and functions for every model '''
     created_date = models.DateTimeField(auto_now_add=True)
     updated_date = models.DateTimeField(auto_now=True)
+    remote_id = models.CharField(max_length=255, null=True)
 
-    @property
-    def absolute_id(self):
-        ''' constructs the absolute reference to any db object '''
-        if hasattr(self, 'remote_id') and self.remote_id:
-            return self.remote_id
-
+    def get_remote_id(self):
+        ''' generate a url that resolves to the local object '''
         base_path = 'https://%s' % DOMAIN
         if hasattr(self, 'user'):
-            base_path = self.user.absolute_id
+            base_path = self.user.remote_id
         model_name = type(self).__name__.lower()
         return '%s/%s/%d' % (base_path, model_name, self.id)
 
     class Meta:
         abstract = True
+
+
+@receiver(models.signals.post_save, sender=FedireadsModel)
+def execute_after_save(sender, instance, created, *args, **kwargs):
+    ''' set the remote_id after save (when the id is available) '''
+    if not created:
+        return
+    instance.remote_id = instance.get_remote_id()
+    instance.save()