diff -r 1817f8946c22 -r faf279e33298 cubicweb/pyramid/resources.py
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/cubicweb/pyramid/resources.py	Mon Sep 26 14:52:12 2016 +0200
@@ -0,0 +1,74 @@
+"""Contains resources classes.
+"""
+from six import text_type
+
+from rql import TypeResolverException
+
+from pyramid.decorator import reify
+from pyramid.httpexceptions import HTTPNotFound
+
+
+class EntityResource(object):
+
+    """A resource class for an entity. It provide method to retrieve an entity
+    by eid.
+    """
+
+    @classmethod
+    def from_eid(cls):
+        def factory(request):
+            return cls(request, None, None, request.matchdict['eid'])
+        return factory
+
+    def __init__(self, request, cls, attrname, value):
+        self.request = request
+        self.cls = cls
+        self.attrname = attrname
+        self.value = value
+
+    @reify
+    def rset(self):
+        req = self.request.cw_request
+        if self.cls is None:
+            return req.execute('Any X WHERE X eid %(x)s',
+                               {'x': int(self.value)})
+        st = self.cls.fetch_rqlst(self.request.cw_cnx.user, ordermethod=None)
+        st.add_constant_restriction(st.get_variable('X'), self.attrname,
+                                    'x', 'Substitute')
+        if self.attrname == 'eid':
+            try:
+                rset = req.execute(st.as_string(), {'x': int(self.value)})
+            except (ValueError, TypeResolverException):
+                # conflicting eid/type
+                raise HTTPNotFound()
+        else:
+            rset = req.execute(st.as_string(), {'x': text_type(self.value)})
+        return rset
+
+
+class ETypeResource(object):
+
+    """A resource for etype.
+    """
+    @classmethod
+    def from_match(cls, matchname):
+        def factory(request):
+            return cls(request, request.matchdict[matchname])
+        return factory
+
+    def __init__(self, request, etype):
+        vreg = request.registry['cubicweb.registry']
+
+        self.request = request
+        self.etype = vreg.case_insensitive_etypes[etype.lower()]
+        self.cls = vreg['etypes'].etype_class(self.etype)
+
+    def __getitem__(self, value):
+        attrname = self.cls.cw_rest_attr_info()[0]
+        return EntityResource(self.request, self.cls, attrname, value)
+
+    @reify
+    def rset(self):
+        rql = self.cls.fetch_rql(self.request.cw_cnx.user)
+        rset = self.request.cw_request.execute(rql)
+        return rset