From 2fde4f4d83bd07d2cd15c2e62e4b97f09064cd62 Mon Sep 17 00:00:00 2001
From: Camilo Nova <camilo.nova@axiacore.com>
Date: Tue, 31 Jan 2017 10:41:55 -0500
Subject: [PATCH] Added the old value to the config_updated signal

---
 constance/backends/database/__init__.py | 3 ++-
 constance/backends/redisd.py            | 3 ++-
 constance/signals.py                    | 2 +-
 docs/index.rst                          | 4 ++--
 4 files changed, 7 insertions(+), 5 deletions(-)

diff --git a/constance/backends/database/__init__.py b/constance/backends/database/__init__.py
index 822531d..97768ba 100644
--- a/constance/backends/database/__init__.py
+++ b/constance/backends/database/__init__.py
@@ -77,6 +77,7 @@ class DatabaseBackend(Backend):
         return value
 
     def set(self, key, value):
+        old_value = self.get(key)
         constance, created = self._model._default_manager.get_or_create(
             key=self.add_prefix(key), defaults={'value': value}
         )
@@ -87,7 +88,7 @@ class DatabaseBackend(Backend):
             self._cache.set(key, value)
 
         signals.config_updated.send(
-            sender=config, updated_key=key, new_value=value
+            sender=config, key=key, old_value=old_value, new_value=value
         )
 
     def clear(self, sender, instance, created, **kwargs):
diff --git a/constance/backends/redisd.py b/constance/backends/redisd.py
index dbb2045..c7d522e 100644
--- a/constance/backends/redisd.py
+++ b/constance/backends/redisd.py
@@ -48,7 +48,8 @@ class RedisBackend(Backend):
                 yield key, loads(value)
 
     def set(self, key, value):
+        old_value = self.get(key)
         self._rd.set(self.add_prefix(key), dumps(value))
         signals.config_updated.send(
-            sender=config, updated_key=key, new_value=value
+            sender=config, key=key, old_value=old_value, new_value=value
         )
diff --git a/constance/signals.py b/constance/signals.py
index fad8198..f0c9796 100644
--- a/constance/signals.py
+++ b/constance/signals.py
@@ -1,5 +1,5 @@
 import django.dispatch
 
 config_updated = django.dispatch.Signal(
-    providing_args=['updated_key', 'new_value']
+    providing_args=['key', 'old_value', 'new_value']
 )
diff --git a/docs/index.rst b/docs/index.rst
index 4fd6645..e5a5a3a 100644
--- a/docs/index.rst
+++ b/docs/index.rst
@@ -81,8 +81,8 @@ You can use it as:
     from constance.signals import config_updated
 
     @receiver(config_updated)
-    def constance_updated(sender, updated_key, new_value, **kwargs):
-        print(sender, updated_key, new_value)
+    def constance_updated(sender, key, old_value, new_value, **kwargs):
+        print(sender, key, old_value, new_value)
 
 The sender is the ``config`` object, and the ``updated_key`` and ``new_value``
 are the ones just changed.