implement match_local_id

Implement MongoDB version of function to look for an existing persistent
NameId for a user.

Author: fredrikt

src/saml2/mongo_store.py

@@ -5,6 +5,8 @@
 from pymongo.mongo_replica_set_client import MongoReplicaSetClient
 import pymongo.uri_parser
 import pymongo.errors
+from saml2.saml import NAMEID_FORMAT_PERSISTENT
+
 from saml2.eptid import Eptid
 from saml2.mdstore import InMemoryMetaData
 from saml2.mdstore import metadata_modules
@@ -163,6 +165,20 @@ def find_local_id(self, name_id):
             return item[self.mdb.primary_key]
         return None
 
+    def match_local_id(self, userid, sp_name_qualifier, name_qualifier):
+        """
+        Look for an existing persistent NameID matching userid,
+        sp_name_qualifier and name_qualifier.
+        """
+        filter = {"name_id.sp_name_qualifier": sp_name_qualifier,
+                  "name_id.name_qualifier": name_qualifier,
+                  "name_id.format": NAMEID_FORMAT_PERSISTENT,
+                  }
+        res = self.mdb.get(value=userid, **filter)
+        if not res:
+            return None
+        return from_dict(res[0]["name_id"], ONTS, True)
+
     def remove_remote(self, name_id):
         cnid = to_dict(name_id, MMODS, True)
         self.mdb.remove(name_id=cnid)