From b23f69b7c727421fd2dab2ff5ccba52fcb26fc7a Mon Sep 17 00:00:00 2001
From: Jeff Jenkins <jeff@qcircles.net>
Date: Thu, 7 Apr 2011 18:55:21 -0400
Subject: [PATCH] Issue 53 -- Separate DB-initated object field setting from
 user intiated

---
 examples/advanced_modeling.py | 36 +++++++++++++++++++++--------------
 examples/hash_field.py        | 30 +++++++++++++++++++++++++++++
 mongoalchemy/document.py      |  6 +++---
 mongoalchemy/fields.py        |  9 ++++++---
 4 files changed, 61 insertions(+), 20 deletions(-)
 create mode 100644 examples/hash_field.py

diff --git a/examples/advanced_modeling.py b/examples/advanced_modeling.py
index b462b44..f75e78e 100644
--- a/examples/advanced_modeling.py
+++ b/examples/advanced_modeling.py
@@ -1,32 +1,40 @@
+'''
+This page is going to go through some more advanced modeling techniques 
+using forward and self-references
+
+'''
+
+
 from mongoalchemy.document import Document, DocumentField
 from mongoalchemy.fields import *
 from datetime import datetime
-
+from pprint import pprint
 class Event(Document):
     name = StringField()
-    children = ListField(DocumentField('Event'), default=[])
-    start = DateTimeField()
+    children = ListField(DocumentField('Event'))
+    begin = DateTimeField()
     end = DateTimeField()
     
     def __init__(self, name, parent=None):
         Document.__init__(self, name=name)
+        self.children = []
         if parent != None:
             parent.children.append(self)
     def __enter__(self):
-        self.start = datetime.utcnow()
+        self.begin = datetime.utcnow()
         return self
     def __exit__(self, exc_type, exc_val, exc_tb):
         self.end = datetime.utcnow()
 
-root = Event('request')
-with Event('main_func', root) as br:
-    with Event('setup', br):
-        pass
-    with Event('handle', br):
-        pass
-    with Event('teardown', br):
+with Event('request') as root:
+    with Event('main_func', root) as br:
+        with Event('setup', br):
+            pass
+        with Event('handle', br):
+            pass
+        with Event('teardown', br):
+            pass
+    with Event('cleanup', root):
         pass
-with Event('cleanup', root):
-    pass
 
-print root.wrap()
+pprint(root.wrap())
diff --git a/examples/hash_field.py b/examples/hash_field.py
new file mode 100644
index 0000000..bc11c34
--- /dev/null
+++ b/examples/hash_field.py
@@ -0,0 +1,30 @@
+from mongoalchemy.document import Document, DocumentField
+from mongoalchemy.fields import *
+from datetime import datetime
+from pprint import pprint
+
+class HashField(StringField):
+    def set_value(self, instance, value, from_db=False):
+        if from_db:
+            super(HashField, self).set_value(instance, value)
+        else:
+            super(HashField, self).set_value(instance, str(hash(value)))
+
+class User(Document):
+    password = HashField()
+    
+from mongoalchemy.session import Session
+session = Session.connect('mongoalchemy-tutorial')
+session.clear_collection(User)
+
+user = User(password='pw')
+print user.password
+user.password = 'newpw'
+print user.password
+
+session.insert(user)
+
+loaded_user = session.query(User).one()
+
+print loaded_user.password
+print loaded_user.password
\ No newline at end of file
diff --git a/mongoalchemy/document.py b/mongoalchemy/document.py
index 524c127..6946c2a 100644
--- a/mongoalchemy/document.py
+++ b/mongoalchemy/document.py
@@ -116,7 +116,7 @@ class Document(object):
         fields which couldn't be mapped can be retrieved (and edited) using
         :func:`~Document.get_extra_fields` '''
     
-    def __init__(self, retrieved_fields=None, **kwargs):
+    def __init__(self, retrieved_fields=None, loading_from_db=False, **kwargs):
         ''' :param retrieved_fields: The names of the fields returned when loading \
                 a partial object.  This argument should not be explicitly set \
                 by subclasses
@@ -141,7 +141,7 @@ def __init__(self, retrieved_fields=None, **kwargs):
                 continue
             
             if name in kwargs:
-                setattr(self, name, kwargs[name])
+                getattr(cls, name).set_value(self, kwargs[name], from_db=loading_from_db)
                 continue
         
         for k in kwargs:
@@ -315,7 +315,7 @@ def unwrap(cls, obj, fields=None):
         
         if fields != None:
             params['retrieved_fields'] = fields
-        obj = cls(**params)
+        obj = cls(loading_from_db=True, **params)
         obj.__mark_clean()
         return obj
     
diff --git a/mongoalchemy/fields.py b/mongoalchemy/fields.py
index 28dc3c9..e2db1ae 100644
--- a/mongoalchemy/fields.py
+++ b/mongoalchemy/fields.py
@@ -183,9 +183,7 @@ def __get__(self, instance, owner):
         
     
     def __set__(self, instance, value):
-        instance._field_values[self.name] = value
-        if self.on_update != 'ignore':
-            instance._dirty[self.name] = self.on_update
+        self.set_value(instance, value)
     
     def __delete__(self, instance):
         if self.name not in instance._field_values:
@@ -193,6 +191,11 @@ def __delete__(self, instance):
         del instance._field_values[self.name]
         instance._dirty[self.name] = '$unset'
     
+    def set_value(self, instance, value, from_db=False):
+        instance._field_values[self.name] = value
+        if self.on_update != 'ignore':
+            instance._dirty[self.name] = self.on_update
+    
     def dirty_ops(self, instance):
         op = instance._dirty.get(self.name)
         if op == '$unset':