Blinker signals added

mongoengine/base.py

@@ -2,6 +2,8 @@ from queryset import QuerySet, QuerySetManager
 from queryset import DoesNotExist, MultipleObjectsReturned
 from queryset import DO_NOTHING
 
+from mongoengine import signals
+
 import sys
 import pymongo
 import pymongo.objectid
@@ -382,6 +384,8 @@ class TopLevelDocumentMetaclass(DocumentMetaclass):
 class BaseDocument(object):
 
     def __init__(self, **values):
+        signals.pre_init.send(self, values=values)
+
         self._data = {}
         # Assign default values to instance
         for attr_name in self._fields.keys():
@@ -395,6 +399,8 @@ class BaseDocument(object):
             except AttributeError:
                 pass
 
+        signals.post_init.send(self)
+
     def validate(self):
         """Ensure that all fields' values are valid and that required fields
         are present.

mongoengine/document.py

@@ -1,3 +1,4 @@
+from mongoengine import signals
 from base import (DocumentMetaclass, TopLevelDocumentMetaclass, BaseDocument,
                   ValidationError)
 from queryset import OperationError
@@ -75,6 +76,8 @@ class Document(BaseDocument):
                 For example, ``save(..., w=2, fsync=True)`` will wait until at least two servers
                 have recorded the write and will force an fsync on each server being written to.
         """
+        signals.pre_save.send(self)
+
         if validate:
             self.validate()
 
@@ -82,6 +85,7 @@ class Document(BaseDocument):
             write_options = {}
 
         doc = self.to_mongo()
+        created = '_id' not in doc
         try:
             collection = self.__class__.objects._collection
             if force_insert:
@@ -96,12 +100,16 @@ class Document(BaseDocument):
         id_field = self._meta['id_field']
         self[id_field] = self._fields[id_field].to_python(object_id)
 
+        signals.post_save.send(self, created=created)
+
     def delete(self, safe=False):
         """Delete the :class:`~mongoengine.Document` from the database. This
         will only take effect if the document has been previously saved.
 
         :param safe: check if the operation succeeded before returning
         """
+        signals.pre_delete.send(self)
+
         id_field = self._meta['id_field']
         object_id = self._fields[id_field].to_mongo(self[id_field])
         try:
@@ -110,6 +118,8 @@ class Document(BaseDocument):
             message = u'Could not delete document (%s)' % err.message
             raise OperationError(message)
 
+        signals.post_delete.send(self)
+
     @classmethod
     def register_delete_rule(cls, document_cls, field_name, rule):
         """This method registers the delete rules to apply when removing this

mongoengine/signals.py

@@ -0,0 +1,41 @@
+# -*- coding: utf-8 -*-
+
+signals_available = False
+try:
+    from blinker import Namespace
+    signals_available = True
+except ImportError:
+    class Namespace(object):
+        def signal(self, name, doc=None):
+            return _FakeSignal(name, doc)
+
+    class _FakeSignal(object):
+        """If blinker is unavailable, create a fake class with the same
+        interface that allows sending of signals but will fail with an
+        error on anything else.  Instead of doing anything on send, it
+        will just ignore the arguments and do nothing instead.
+        """
+
+        def __init__(self, name, doc=None):
+            self.name = name
+            self.__doc__ = doc
+
+        def _fail(self, *args, **kwargs):
+            raise RuntimeError('signalling support is unavailable '
+                               'because the blinker library is '
+                               'not installed.')
+        send = lambda *a, **kw: None
+        connect = disconnect = has_receivers_for = receivers_for = \
+            temporarily_connected_to = _fail
+        del _fail
+
+# the namespace for code signals.  If you are not mongoengine code, do
+# not put signals in here.  Create your own namespace instead.
+_signals = Namespace()
+
+pre_init = _signals.signal('pre_init')
+post_init = _signals.signal('post_init')
+pre_save = _signals.signal('pre_save')
+post_save = _signals.signal('post_save')
+pre_delete = _signals.signal('pre_delete')
+post_delete = _signals.signal('post_delete')