4 files changed, 37 insertions, 5 deletions
diff --git a/rdflib/plugins/serializers/rdfxml.py b/rdflib/plugins/serializers/rdfxml.py
index 631c8fe0..4242fc05 100644
--- a/rdflib/plugins/serializers/rdfxml.py
+++ b/rdflib/plugins/serializers/rdfxml.py
@@ -46,7 +46,11 @@ class XMLSerializer(Serializer):
             yield prefix, namespace
 
     def serialize(self, stream, base=None, encoding=None, **args):
-        self.base = base
+        # if base is given here, use that, if not and a base is set for the graph use that
+        if base is not None:
+            self.base = base
+        elif self.store.base is not None:
+            self.base = self.store.base
         self.__stream = stream
         self.__serialized = {}
         encoding = self.encoding
@@ -62,6 +66,8 @@ class XMLSerializer(Serializer):
         # If provided, write xml:base attribute for the RDF
         if "xml_base" in args:
             write('   xml:base="%s"\n' % args['xml_base'])
+        elif self.base:
+            write('   xml:base="%s"\n' % self.base)
         # TODO:
         # assert(
         #    namespaces["http://www.w3.org/1999/02/22-rdf-syntax-ns#"]=='rdf')
@@ -163,7 +169,11 @@ class PrettyXMLSerializer(Serializer):
     def serialize(self, stream, base=None, encoding=None, **args):
         self.__serialized = {}
         store = self.store
-        self.base = base
+        # if base is given here, use that, if not and a base is set for the graph use that
+        if base is not None:
+            self.base = base
+        elif store.base is not None:
+            self.base = store.base
         self.max_depth = args.get("max_depth", 3)
         assert self.max_depth > 0, "max_depth must be greater than 0"
 
@@ -184,6 +194,8 @@ class PrettyXMLSerializer(Serializer):
 
         if "xml_base" in args:
             writer.attribute(XMLBASE, args["xml_base"])
+        elif self.base:
+            writer.attribute(XMLBASE, self.base)
 
         writer.namespaces(namespaces.items())
 
diff --git a/rdflib/plugins/serializers/trig.py b/rdflib/plugins/serializers/trig.py
index 6c05ad75..250e1c09 100644
--- a/rdflib/plugins/serializers/trig.py
+++ b/rdflib/plugins/serializers/trig.py
@@ -39,7 +39,7 @@ class TrigSerializer(TurtleSerializer):
             for triple in context:
                 self.preprocessTriple(triple)
 
-            self._contexts[context]=(self.orderSubjects(), self._subjects, self._references)
+            self._contexts[context] = (self.orderSubjects(), self._subjects, self._references)
 
     def reset(self):
         super(TrigSerializer, self).reset()
@@ -49,7 +49,11 @@ class TrigSerializer(TurtleSerializer):
                   spacious=None, **args):
         self.reset()
         self.stream = stream
-        self.base = base
+        # if base is given here, use that, if not and a base is set for the graph use that
+        if base is not None:
+            self.base = base
+        elif self.store.base is not None:
+            self.base = self.store.base
 
         if spacious is not None:
             self._spacious = spacious
diff --git a/rdflib/plugins/serializers/trix.py b/rdflib/plugins/serializers/trix.py
index fceec6bd..0a574493 100644
--- a/rdflib/plugins/serializers/trix.py
+++ b/rdflib/plugins/serializers/trix.py
@@ -29,6 +29,11 @@ class TriXSerializer(Serializer):
         self.writer = XMLWriter(stream, nm, encoding, extra_ns={"": TRIXNS})
 
         self.writer.push(TRIXNS[u"TriX"])
+        # if base is given here, use that, if not and a base is set for the graph use that
+        if base is None and self.store.base is not None:
+            base = self.store.base
+        if base is not None:
+            self.writer.attribute("http://www.w3.org/XML/1998/namespacebase", base)
         self.writer.namespaces()
 
         if isinstance(self.store, ConjunctiveGraph):
@@ -44,6 +49,8 @@ class TriXSerializer(Serializer):
 
     def _writeGraph(self, graph):
         self.writer.push(TRIXNS[u"graph"])
+        if graph.base:
+            self.writer.attribute("http://www.w3.org/XML/1998/namespacebase", graph.base)
         if isinstance(graph.identifier, URIRef):
             self.writer.element(
                 TRIXNS[u"uri"], content=text_type(graph.identifier))
diff --git a/rdflib/plugins/serializers/turtle.py b/rdflib/plugins/serializers/turtle.py
index 1c58ba1b..8a41587c 100644
--- a/rdflib/plugins/serializers/turtle.py
+++ b/rdflib/plugins/serializers/turtle.py
@@ -224,7 +224,11 @@ class TurtleSerializer(RecursiveSerializer):
                   spacious=None, **args):
         self.reset()
         self.stream = stream
-        self.base = base
+        # if base is given here, use that, if not and a base is set for the graph use that
+        if base is not None:
+            self.base = base
+        elif self.store.base is not None:
+            self.base = self.store.base
 
         if spacious is not None:
             self._spacious = spacious
@@ -246,6 +250,8 @@ class TurtleSerializer(RecursiveSerializer):
         self.endDocument()
         stream.write(b("\n"))
 
+        self.base = None
+
     def preprocessTriple(self, triple):
         super(TurtleSerializer, self).preprocessTriple(triple)
         for i, node in enumerate(triple):
@@ -291,6 +297,9 @@ class TurtleSerializer(RecursiveSerializer):
     def startDocument(self):
         self._started = True
         ns_list = sorted(self.namespaces.items())
+
+        if self.base:
+            self.write(self.indent() + '@base <%s> .\n' % self.base)
         for prefix, uri in ns_list:
             self.write(self.indent() + '@prefix %s: <%s> .\n' % (prefix, uri))
         if ns_list and self._spacious: