GET root node; initial bootstrap data set.

data/bootstrap/simple_layout.trig

@@ -0,0 +1,9 @@
+# Bootstrap data for simple RDF store layout.
+
+PREFIX ldp: <http://www.w3.org/ns/ldp#>
+PREFIX fcrepo: <http://fedora.info/definitions/v4/repository#>
+
+<urn:fcsystem:root>
+  a ldp:RDFSource , ldp:Container , ldp:BasicContainer ,
+    fcrepo:RepositoryRoot , fcrepo:Resource , fcrepo:Container ;
+  .

lakesuperior/model/ldpr.py

@@ -151,9 +151,16 @@ class Ldpr(metaclass=ABCMeta):
         store_mod = import_module(
                 'lakesuperior.store_layouts.rdf.{}'.format(
                         self.rdf_store_layout))
+        # Ideally, _rdf_store_cls should not be a class member, but
+        # `_find_parent_or_create_pairtree` is using it at the moment. That
+        # should be fixed some time.
         self._rdf_store_cls = getattr(store_mod, Translator.camelcase(
                 self.rdf_store_layout))
-        self.rdfly = self._rdf_store_cls(self.urn)
+
+        self._urn = nsc['fcres'][uuid] if self.uuid is not None \
+                else self._rdf_store_cls.ROOT_NODE_URN
+
+        self.rdfly = self._rdf_store_cls(self._urn)
 
         # Same thing coud be done for the filesystem store layout, but we
         # will keep it simple for now.
@@ -169,8 +176,7 @@ class Ldpr(metaclass=ABCMeta):
 
         @return rdflib.URIRef
         '''
-        return nsc['fcres'][self.uuid]
-
+        return self._urn
 
     @property
     def uri(self):

lakesuperior/store_layouts/rdf/base_rdf_layout.py

@@ -59,6 +59,7 @@ class BaseRdfLayout(metaclass=ABCMeta):
     - Methods starting with `ask_` return a boolean value.
     '''
 
+    ROOT_NODE_URN = nsc['fcsystem'].root
     # N.B. This is Fuseki-specific.
     UNION_GRAPH_URI = URIRef('urn:x-arq:UnionGraph')
 

lakesuperior/util/translator.py

@@ -2,6 +2,7 @@ from flask import request
 from rdflib.term import URIRef
 
 from lakesuperior.core.namespaces import ns_collection as nsc
+from lakesuperior.store_layouts.rdf.base_rdf_layout import BaseRdfLayout
 
 
 class Translator:
@@ -66,6 +67,8 @@ class Translator:
 
         @return rdflib.term.URIRef
         '''
+        if urn == BaseRdfLayout.ROOT_NODE_URN:
+            urn = nsc['fcres']
         return URIRef(Translator.globalize_string(str(urn)))
 
 
@@ -74,22 +77,25 @@ class Translator:
         '''
         Globalize a graph.
         '''
+        from lakesuperior.model.ldpr import Ldpr
         q = '''
         CONSTRUCT {{ ?s ?p ?o . }} WHERE {{
           {{
             ?s ?p ?o .
-            FILTER STRSTARTS(str(?s), "{0}") .
+            FILTER (
+              STRSTARTS(str(?s), "{0}")
+              ||
+              STRSTARTS(str(?o), "{0}")
+              ||
+              STRSTARTS(str(?s), "{1}")
+              ||
+              STRSTARTS(str(?o), "{1}")
+            ) .
           }}
-          UNION
-          {{
-            ?s ?p ?o .
-            FILTER STRSTARTS(str(?o), "{0}") .
-          }}
-        }}'''.format(nsc['fcres'])
+        }}'''.format(nsc['fcres'], BaseRdfLayout.ROOT_NODE_URN)
         flt_g = g.query(q)
 
         for t in flt_g:
-            print('Triple: {}'.format(t))
             global_s = Translator.globalize_term(t[0])
             global_o = Translator.globalize_term(t[2]) \
                     if isinstance(t[2], URIRef) \