Allow getting a user by id and nickname.

tahrir_api/dbapi.py

@@ -154,18 +154,32 @@ def get_person_email(self, person_id):
                                          id=person_id).one().email
         return None
 
-    def get_person(self, person_email):
+    def get_person(self, person_email=None, id=None, nickname=None):
         """
-        Convience function to retrieve a person object from an email
+        Convenience function to retrieve a person object from an email,
+        id, or nickname.
 
         :type person_email: str
         :param person_email: The email address of a Person in the database
+
+        :type id: str
+        :param id: The id of a Person in the database
+
+        :type nickname: str
+        :param nickname: The nickname of a Person in the database
         """
 
         session = scoped_session(self.session_maker)
-        if self.person_exists(email=person_email):
-            return session.query(Person).filter_by(email=person_email).one()
-        return None
+        query = session.query(Person)
+
+        if person_email and self.person_exists(email=person_email):
+            return query.filter_by(email=person_email).one()
+        elif id and self.person_exists(id=id):
+            return query.filter_by(id=id).one()
+        elif nickname and self.person_exists(nickname=nickname):
+            return query.filter_by(nickname=nickname).one()
+        else:
+            return None
 
     def delete_person(self, person_email):
         """