Refactored relations

uffd/ldaporm.py

@@ -40,6 +40,7 @@ class LDAPSession:
 	def __init__(self):
 		self.__objects = {} # dn -> instance
 		self.__to_delete = []
+		self.__relations = {} # (srccls, srcattr, dn) -> {srcobj, ...}
 
 	def lookup(self, dn):
 		return self.__objects.get(dn)
@@ -50,6 +51,20 @@ class LDAPSession:
 		self.__objects[obj.dn] = obj
 		return obj
 
+	def lookup_relations(self, srccls, srcattr, dn):
+		key = (srccls, srcattr, dn)
+		return self.__relations.get(key, set())
+
+	def update_relations(self, srcobj, srcattr, delete_dns=None, add_dns=None):
+		for dn in (delete_dns or []):
+			key = (type(srcobj), srcattr, dn)
+			self.__relations[key] = self.__relations.get(key, set())
+			self.__relations[key].discard(srcobj)
+		for dn in (add_dns or []):
+			key = (type(srcobj), srcattr, dn)
+			self.__relations[key] = self.__relations.get(key, set())
+			self.__relations[key].add(srcobj)
+
 	def add(self, obj):
 		if obj.ldap_created:
 			raise Exception()
@@ -147,64 +162,46 @@ class LDAPAttribute:
 			values = [values]
 		obj.ldap_setattr(self.name, [self.encode(value) for value in values])
 
-class LDAPRelationBackref:
-	def __init__(self, src, srcattr):
-		self.src = src
+class LDAPBackref:
+	def __init__(self, srccls, srcattr):
+		self.srccls = srccls
 		self.srcattr = srcattr
-		self.key = (self.src, self.srcattr)
-
-	def fetch(self, obj):
-		if self.key not in obj._relation_data:
-			kwargs = {getattr(self.src, self.srcattr).name: obj.dn}
-			values = self.src.ldap_filter_by(**kwargs)
-			obj._relation_data[self.key] = set(values)
-		return obj._relation_data[self.key]
-
-	def add(self, obj, value):
-		self.fetch(obj)
-		obj._relation_data[self.key].add(value)
+		if srccls.ldap_relations is None:
+			srccls.ldap_relations = set()
+		srccls.ldap_relations.add(srcattr)
 
-	def discard(self, obj, value):
-		self.fetch(obj)
-		obj._relation_data[self.key].discard(value)
+	def init(self, obj):
+		if self.srcattr in obj.ldap_relation_data:
+			return
+		# The query instanciates all related objects that in turn add their relations to session
+		self.srccls.ldap_filter_by(**{self.srcattr: obj.dn})
+		obj.ldap_relation_data.add(self.srcattr)
 
 	def __get__(self, obj, objtype=None):
 		if obj is None:
 			return self
-		return LDAPSet(getitems=lambda: self.fetch(obj),
-									 additem=lambda value: getattr(value, self.srcattr).add(obj),
-									 delitem=lambda value: getattr(value, self.srcattr).discard(obj))
+		self.init(obj)
+		return LDAPSet(getitems=lambda: ldap.session.lookup_relations(self.srccls, self.srcattr, obj.dn),
+									 additem=lambda value: value.ldap_attradd(self.srcattr, obj.dn),
+									 delitem=lambda value: value.ldap_attrdel(self.srcattr, obj.dn))
+
+	def __set__(self, obj, values):
+		current = self.__get__(obj)
+		current.clear()
+		for value in values:
+			current.add(value)
 
-class LDAPRelation:
+class LDAPRelation(LDAPAttribute):
 	def __init__(self, name, dest, backref=None):
+		super().__init__(name, multi=True, encode=lambda value: value.dn,
+		                 decode=lambda value: dest.ldap_get(value))
 		self.name = name
 		self.dest = dest
 		self.backref = backref
 
 	def __set_name__(self, cls, name):
 		if self.backref is not None:
-			setattr(self.dest, self.backref, LDAPRelationBackref(cls, name))
-
-	def add(self, obj, destdn):
-		destobj = self.dest.ldap_get(destdn) # Always from cache!
-		obj.ldap_attradd(self.name, destdn)
-		if self.backref is not None:
-			getattr(self.dest, self.backref).add(destobj, obj)
-
-	def discard(self, obj, destdn):
-		destobj = self.dest.ldap_get(destdn) # Always from cache!
-		obj.ldap_attrdel(self.name, destdn)
-		if self.backref is not None:
-			getattr(self.dest, self.backref).discard(destobj, obj)
-	
-	def __get__(self, obj, objtype=None):
-		if obj is None:
-			return self
-		return LDAPSet(getitems=lambda: obj.ldap_getattr(self.name),
-		               additem=lambda value: self.add(obj, value),
-		               delitem=lambda value: self.discard(obj, value),
-		               encode=lambda value: value.dn,
-		               decode=lambda value: self.dest.ldap_get(value))
+			setattr(self.dest, self.backref, LDAPBackref(cls, self.name))
 
 class LDAPModel:
 	ldap_dn_attribute = None
@@ -213,9 +210,10 @@ class LDAPModel:
 	ldap_object_classes = None
 	ldap_filter = None
 	ldap_defaults = None # Populated by LDAPAttribute
+	ldap_relations = None # Populated by LDAPBackref
 
 	def __init__(self, _ldap_dn=None, _ldap_attributes=None, **kwargs):
-		self._relation_data = {}
+		self.ldap_relation_data = set()
 		self.__ldap_dn = _ldap_dn
 		self.__ldap_attributes = {}
 		for key, values in (_ldap_attributes or {}).items():
@@ -229,22 +227,32 @@ class LDAPModel:
 			if not hasattr(self, key):
 				raise Exception()
 			setattr(self, key, value)
+		for name in (self.ldap_relations or []):
+			self.__update_relations(name, add_dns=self.__attributes.get(name, []))
+
+	def __update_relations(self, name, delete_dns=None, add_dns=None):
+		if name in (self.ldap_relations or []):
+			ldap.session.update_relations(self, name, delete_dns, add_dns)
 
 	def ldap_getattr(self, name):
 		return self.__attributes.get(name, [])
 
 	def ldap_setattr(self, name, values):
+		self.__update_relations(name, delete_dns=self.__attributes.get(name, []))
 		self.__changes[name] = [(MODIFY_REPLACE, values)]
 		self.__attributes[name] = values
+		self.__update_relations(name, add_dns=values)
 
-	def ldap_attradd(self, name, item):
-		self.__changes[name] = self.__changes.get(name, []) + [(MODIFY_ADD, [item])]
-		self.__attributes[name].append(item)
+	def ldap_attradd(self, name, value):
+		self.__changes[name] = self.__changes.get(name, []) + [(MODIFY_ADD, [value])]
+		self.__attributes[name].append(value)
+		self.__update_relations(name, add_dns=[value])
 
-	def ldap_attrdel(self, name, item):
-		self.__changes[name] = self.__changes.get(name, []) + [(MODIFY_DELETE, [item])]
-		if item in self.__attributes.get(name, []):
-			self.__attributes[name].remove(item)
+	def ldap_attrdel(self, name, value):
+		self.__changes[name] = self.__changes.get(name, []) + [(MODIFY_DELETE, [value])]
+		if value in self.__attributes.get(name, []):
+			self.__attributes[name].remove(value)
+		self.__update_relations(name, delete_dns=[value])
 
 	def __repr__(self):
 		name = '%s.%s'%(type(self).__module__, type(self).__name__)
@@ -302,8 +310,12 @@ class LDAPModel:
 		return res
 
 	def ldap_reset(self):
+		for name in (self.ldap_relations or []):
+			self.__update_relations(name, delete_dns=self.__attributes.get(name, []))
 		self.__changes = {}
 		self.__attributes = deepcopy(self.__ldap_attributes)
+		for name in (self.ldap_relations or {}):
+			self.__update_relations(name, add_dns=self.__attributes.get(name, []))
 
 	@property
 	def ldap_dirty(self):
@@ -374,6 +386,7 @@ class Group(LDAPModel):
 	gid = LDAPAttribute('gidNumber')
 	name = LDAPAttribute('cn')
 	description = LDAPAttribute('description', default='')
+	member_dns= LDAPAttribute('uniqueMember', multi=True)
 
 	members = LDAPRelation('uniqueMember', User, backref='groups')