Add funcs to handle email nonces

gratipay/security/authentication/__init__.py

@@ -1 +1,4 @@
+"""Gratipay authentication module.
+"""
+
 from __future__ import absolute_import, division, print_function, unicode_literals

gratipay/security/authentication/email.py

@@ -0,0 +1,59 @@
+import datetime
+import uuid
+
+from aspen.utils import utcnow
+
+class VerificationResult(object):
+    def __init__(self, name):
+        self.name = name
+    def __repr__(self):
+        return "<VerificationResult: %r>" % self.name
+    __str__ = __repr__
+
+#: Signal that the nonce doesn't exist in our database
+NONCE_INVALID = VerificationResult('Invalid')
+
+#: Signal that the nonce exists, but has expired
+NONCE_EXPIRED = VerificationResult('Expired')
+
+#: Signal that the nonce exists, and is valid
+NONCE_VALID   = VerificationResult('Valid')
+
+#: Time for nonce to expire
+NONCE_EXPIRY_MINUTES = 60
+
+def create_signin_nonce(db, email_address):
+    nonce = str(uuid.uuid4())
+    db.run("""
+        INSERT INTO email_auth_nonces (email_address, intent, nonce)
+             VALUES (
+                        %(email_address)s,
+                        'sign-in',
+                        %(nonce)s
+                    )
+    """, locals())
+
+    return nonce
+
+def verify_nonce(db, email_address, nonce):
+    record = db.one("""
+        SELECT email_address, ctime, intent
+          FROM email_auth_nonces
+         WHERE nonce = %(nonce)s
+           AND email_address = %(email_address)s
+    """, locals(), back_as=dict)
+
+    if not record:
+        return NONCE_INVALID
+
+    if utcnow() - record['ctime'] > datetime.timedelta(minutes=NONCE_EXPIRY_MINUTES):
+        return NONCE_EXPIRED
+
+    return NONCE_VALID
+
+def invalidate_nonce(db, email_address, nonce):
+    db.run("""
+        DELETE FROM email_auth_nonces
+         WHERE nonce = %(nonce)s
+           AND email_address = %(email_address)s
+    """, locals())

tests/py/security/authentication/test_email_signin.py

@@ -0,0 +1,77 @@
+# -*- coding: utf-8 -*-
+from __future__ import absolute_import, division, print_function, unicode_literals
+from uuid import UUID
+
+from psycopg2 import IntegrityError
+import pytest
+
+from gratipay.security.authentication.email import create_signin_nonce, verify_nonce, invalidate_nonce
+from gratipay.security.authentication.email import NONCE_VALID, NONCE_INVALID, NONCE_EXPIRED
+from gratipay.testing import Harness
+
+class TestCreateSigninNonce(Harness):
+
+    def setUp(self):
+        alice = self.make_participant('alice')
+        self.add_and_verify_email(alice, '[email protected]')
+
+    def _fetch_rec_from_db(self, nonce):
+        return self.db.one("SELECT * FROM email_auth_nonces WHERE nonce = %s", (nonce, ), back_as=dict)
+
+    def test_inserts_into_db(self):
+        nonce = create_signin_nonce(self.db, '[email protected]')
+        rec = self._fetch_rec_from_db(nonce)
+
+        assert rec['nonce'] == nonce
+        assert rec['intent'] == 'sign-in'
+        assert rec['email_address'] == '[email protected]'
+
+    def test_nonce_is_valid_uuid(self):
+        nonce = create_signin_nonce(self.db, '[email protected]')
+
+        assert UUID(nonce, version=4).__class__ == UUID
+
+
+class TestVerifyNonce(Harness):
+
+    def setUp(self):
+        alice = self.make_participant('alice')
+        self.add_and_verify_email(alice, '[email protected]')
+
+    def test_valid_nonce(self):
+        nonce = create_signin_nonce(self.db, '[email protected]')
+        assert verify_nonce(self.db, '[email protected]',  nonce) == NONCE_VALID
+
+    def test_expired_nonce(self):
+        nonce = create_signin_nonce(self.db, '[email protected]')
+        self.db.run("UPDATE email_auth_nonces SET ctime = ctime - interval '1 day'")
+        assert verify_nonce(self.db, '[email protected]',  nonce) == NONCE_EXPIRED
+
+    def test_invalid_nonce(self):
+        create_signin_nonce(self.db, '[email protected]')
+        assert verify_nonce(self.db, '[email protected]',  "dummy_nonce") == NONCE_INVALID
+
+class TestInvalidateNonce(Harness):
+
+    def setUp(self):
+        alice = self.make_participant('alice')
+        self.add_and_verify_email(alice, '[email protected]')
+
+    def test_deletes_nonce(self):
+        nonce = create_signin_nonce(self.db, '[email protected]')
+        invalidate_nonce(self.db, '[email protected]', nonce)
+
+        assert verify_nonce(self.db, '[email protected]', nonce) == NONCE_INVALID
+
+    def test_only_deletes_one_nonce(self):
+        nonce1 = create_signin_nonce(self.db, '[email protected]')
+        nonce2 = create_signin_nonce(self.db, '[email protected]')
+        invalidate_nonce(self.db, '[email protected]', nonce1)
+
+        assert verify_nonce(self.db, '[email protected]', nonce1) == NONCE_INVALID
+        assert verify_nonce(self.db, '[email protected]', nonce2) == NONCE_VALID
+
+    def test_tolerates_invalidated_nonce(self):
+        nonce = create_signin_nonce(self.db, '[email protected]')
+        invalidate_nonce(self.db, '[email protected]', nonce)
+        invalidate_nonce(self.db, '[email protected]', nonce) # Should not throw an error