Fixed update of DSObjects

1 files changed, 48 insertions, 3 deletions

diff --git a/common/src/semanticxo/semanticdatastore.py b/common/src/semanticxo/semanticdatastore.py
index 287e977..6ebff24 100644
--- a/common/src/semanticxo/semanticdatastore.py
+++ b/common/src/semanticxo/semanticdatastore.py
@@ -29,7 +29,8 @@ class SemanticDSEntry(object):
 		logging.debug("[SDS] Create entry with parent %s and uid %s", parent, uid)
 		self._resource_uri = OLPC_RESOURCE[uid]
 		self._parent = parent
-		self._parent.add(self._resource_uri, RDF.type, OLPC_TERMS[category])
+		self._type = OLPC_TERMS[category]
+		self._parent.add(self._resource_uri, RDF.type, self._type)
 		self._parent.add(self._resource_uri, OLPC_TERMS['uid'], Literal(uid))
 		
 	def get_resource_uri(self):
@@ -45,6 +46,15 @@ class SemanticDSEntry(object):
 		target_uri = target.get_resource_uri()
 		self._parent.add(self._resource_uri, OLPC_TERMS[link_name], target_uri)
 	
+	def clean(self):
+		'''
+		Erase all the triples associated to this resource
+		'''
+		# remove all
+		self._parent.remove(self._resource_uri, None, None)
+		# add the type again
+		self._parent.add(self._resource_uri, RDF.type, self._type)
+	
 	def parse_metadata(self, metadata):
 		'''
 		Turn metadata about a resource into triples
@@ -108,6 +118,12 @@ class SemanticDSObject(object):
 		'''
 		self._graph.add((s, p, o))
 		
+	def remove(self, s, p, o):
+		'''
+		Remove a raw triple
+		'''
+		self._graph.remove((s, p, o))
+		
 	def create_entry(self, uid=None, category=None):
 		'''
 		Return a new object entry to be added to an instance of SemanticDSObject
@@ -117,7 +133,11 @@ class SemanticDSObject(object):
 		if uid == None:
 			uid = str(uuid.uuid4())
 		return SemanticDSEntry(parent=self, uid=uid, category=category)
-	
+
+	def get_entry(self, uid, category):
+		return SemanticDSEntry(parent=self, uid=uid, category=category)
+		
+
 class SemanticDS(object):
 	'''
 	The Semantic DataStore is an interface to the triple store.		 
@@ -184,7 +204,32 @@ class SemanticDS(object):
 		graph_iri = OLPC_GRAPHS[uid]
 		return SemanticDSObject(graph_iri)
 
-			
+	def get_object_by_content(self, uid):
+		'''
+		Return an object which contains a description about UID
+		'''
+		# First, try to find a graph
+		query_string = """
+			SELECT DISTINCT ?graph WHERE { 
+			GRAPH ?graph {?s <%s> '%s'}. 
+			?graph a <%s>. 
+			}
+		""" % (OLPC_TERMS['uid'], uid, OLPC_TERMS['DataGraph'])
+		sparql = SPARQLWrapper("http://%s/sparql" % self.store_address)
+		sparql.setReturnFormat(Wrapper.JSON)
+		sparql.setQuery(query_string)
+		results = sparql.query().convert()
+		graphs = [result["graph"]["value"] for result in results["results"]["bindings"]]
+		if len(graphs) == 0:
+			return None
+		
+		# Load the object
+		query_string = "CONSTRUCT {?s ?p ?o} WHERE { GRAPH <%s> {?s ?p ?o} }" % graphs[0]
+		sparql = SPARQLWrapper("http://%s/sparql" % self.store_address)
+		sparql.setReturnFormat(Wrapper.XML)
+		sparql.setQuery(query_string)
+		return SemanticDSObject(graphs[0], sparql.query().convert())
+		
 	def get_metadata(self, uid, properties=None):
 		resource_iri = OLPC_RESOURCE[uid]
 		metadata = {}