Changeset 76 for trunk/dbpickle/dbpickle.py

Timestamp:

02/27/07 10:24:21 (3 years ago)

Author:

akaihola

Message:

Added plugin feature to dbpickle.

Files:

• trunk/dbpickle/dbpickle.py (modified) (8 diffs)

trunk/dbpickle/dbpickle.py

@@ -31 +31 @@
 primary key.  ManyToMany and OneToOne relations are not supported.
 
+You can also use you own plugin for pre-processing objects before
+saving them into the database.  This is useful e.g. when a model has
+changed and you're importing objects from an old version of the
+database.  The plugin should be a Python program with a
+`pre_save_hook(obj)` function which returns True if it modified the
+object, otherwise False.
+
+
+Usage example
+=============
+
 Let's suppose your project is using PostgreSQL and the database has
 been populated using the app.
@@ -56 +67 @@
 import logging
 from django.db import models
+from imp import load_source
 
 def dump(filepath):
@@ -72 +84 @@
 
 @transaction.commit_on_success
-def load(filepath):
+def load(filepath, pluginpath=None):
     """
     Unpickle Django objects from the given file and save them into the
     database.
     """
+
+    if pluginpath:
+        plugin = load_source('plugin', pluginpath)
+    else:
+        plugin = None
+
+    pre_save_hook = getattr(plugin, 'pre_save_hook', lambda obj: False)
     
     # unpickle objects from file
@@ -90 +109 @@
     while data:
         key, obj = data.popitem()
-        load_recursive(data, obj)
+        load_recursive(data, obj, pre_save_hook)
 
 
-def load_recursive(data, obj):
+def load_recursive(data, obj, pre_save_hook):
     """
     Save the given object into the database.  If the object has
@@ -109 +128 @@
                                         related_model,
                                         related_pk_val))
-                load_recursive(data, related_obj)
+                load_recursive(data, related_obj, pre_save_hook)
             except KeyError:
                 logging.debug('probably loaded already: '
@@ -116 +135 @@
     logging.info('loading %s' % obj)
     try:
+        pre_save_hook(obj)
         obj.save()
     except Exception, e:
@@ -127 +147 @@
     p.add_option('-l', '--load', action='store_const', const='load', dest='action', help='Load all Django objects from a file')
     p.add_option('-f', '--file', default='djangodb.pickle', help='Specify file path [djangodb.pickle]')
+    p.add_option('-p', '--plugin', help='Use .py plugin for preprocessing objects to load')
     p.add_option('-v', '--verbose' , action='store_true', help='Show verbose output for debugging')
     (opts, args) = p.parse_args()
@@ -134 +155 @@
         dump(opts.file)
     elif opts.action == 'load':
-        load(opts.file)
+        load(opts.file, opts.plugin)
     else:
         print 'Please specify --dump or --load'