Changeset 312

Timestamp:

03/24/08 21:10:57 (5 years ago)

Author:

cleverdevil

Message:

Two changes to the versioning extension:

• Applied a patch resolving ticket 35, so that the extension respects the current transaction.
  
• Added an optional check_concurrency keyword argument to the extension, supporting the usage of SQLAlchemy's built-in optimistic concurrency check.
  

Location:

elixir/trunk

Files:

• elixir/ext/versioned.py (modified) (7 diffs)
• tests/test_versioning.py (modified) (1 diff)

elixir/trunk/elixir/ext/versioned.py

@@ -37 +37 @@
 The acts_as_versioned statement also accepts an optional `ignore` argument 
 that consists of a list of strings, specifying names of fields.  Changes in 
-those fields will not result in a version increment.
+those fields will not result in a version increment.  In addition, you can
+pass in an optional `check_concurrent` argument, which will use SQLAlchemy's
+built-in optimistic concurrency mechanisms. 
 
 Note that relationships that are stored in mapping tables will not be included
@@ -104 +106 @@
                 # the instance was really updated, so we create a new version
                 colvalues = dict(values.items()) 
-                instance.__class__.__history_table__.insert().execute(colvalues) 
+                connection.execute(instance.__class__.__history_table__.insert(), colvalues)
                 instance.version = instance.version + 1
                 instance.timestamp = datetime.now()
@@ -112 +114 @@
         
     def before_delete(self, mapper, connection, instance):
-        instance.__history_table__.delete(
+        connection.execute(instance.__history_table__.delete(
             get_history_where(instance)
-        ).execute()
+        ))
         return EXT_PASS
 
@@ -127 +129 @@
 class VersionedEntityBuilder(object):
         
-    def __init__(self, entity, ignore=[]):
+    def __init__(self, entity, ignore=[], check_concurrent=False):
         entity._descriptor.add_mapper_extension(versioned_mapper_extension)
         self.entity = entity
+        self.check_concurrent = check_concurrent
+        
         # Changes in these fields will be ignored
         entity.__ignored_fields__ = ignore
@@ -140 +144 @@
         self.entity._descriptor.add_column(version_col)
         self.entity._descriptor.add_column(timestamp_col)
+        
+        # add a concurrent_version column to the entity, if required
+        if self.check_concurrent:
+            self.entity._descriptor.version_id_col = 'concurrent_version'
    
     # we copy columns from the main entity table, so we need it to exist first
     def after_table(self):
         entity = self.entity
-
+        
         # look for events
         after_revert_events = []
@@ -153 +161 @@
         # create a history table for the entity
         #TODO: fail more noticeably in case there is a version col
-        columns = [column.copy() for column in entity.table.c 
-                                 if column.name != 'version']
+        columns = [
+            column.copy() for column in entity.table.c 
+            if column.name not in ('version', 'concurrent_version')
+        ]
         columns.append(Column('version', Integer, primary_key=True))
         table = Table(entity.table.name + '_history', entity.table.metadata, 
@@ -222 +232 @@
             differences = {}
             for column in self.c:
-                if column.name == 'version':
+                if column.name in ('version', 'concurrent_version'):
                     continue
                 this = getattr(self, column.name)

elixir/trunk/tests/test_versioning.py

@@ -145 +145 @@
         assert movie.version == 4
         assert movie.versions[-2].description == "description 3"
+
+        # Updates to the history table must be inside the transaction
+        session.begin()
+        movie = Movie(id=3, title='Foo', description='1')
+        session.commit();
+        
+        session.begin()
+        movie.description = '2'
+        session.flush()
+        session.rollback()
+        session.clear()
+        
+        session.begin()
+        movie = Movie.get_by(title='Foo')
+        movie.description = '3'
+        session.commit()
+