Method set_new_identity for change identity (#237)

Author: achernetsky

aiohttp_session/__init__.py

@@ -68,6 +68,13 @@ def invalidate(self):
         self._changed = True
         self._mapping = {}
 
+    def set_new_identity(self, identity):
+        if not self._new:
+            raise RuntimeError(
+                "Can't change identity for a session which is not new")
+
+        self._identity = identity
+
     def __len__(self):
         return len(self._mapping)
 

docs/reference.rst

@@ -90,7 +90,7 @@ Session
    .. attribute:: identity
 
       Client's identity. It may be cookie name or database
-      key. Read-only property.
+      key. Read-only property. For change use :func:`Session.set_new_identity`.
 
    .. attribute:: new
 
@@ -130,6 +130,13 @@ Session
       Call this when you want to invalidate the session (dump all
       data, and -- perhaps -- set a clearing cookie).
 
+   .. method:: set_new_identity(identity)
+
+      Call this when you want to change the :py:attr:`identity`.
+
+      .. warning::
+
+         Never change :py:attr:`identity` of a session which is not new.
 
 .. _aiohttp-session-storage:
 

tests/test_session_dict.py

@@ -1,3 +1,4 @@
+import pytest
 import time
 
 from aiohttp_session import Session
@@ -31,6 +32,22 @@ def test_create3():
     assert s.created is not None
 
 
+def test_set_new_identity_ok():
+    s = Session(identity=1, data=None, new=True)
+    assert s.new
+    assert s.identity == 1
+
+    s.set_new_identity(2)
+    assert s.new
+    assert s.identity == 2
+
+
+def test_set_new_identity_for_not_new_session():
+    s = Session(identity=1, data=None, new=False)
+    with pytest.raises(RuntimeError):
+        s.set_new_identity(2)
+
+
 def test__repr__():
     s = Session('test_identity', data=None, new=True)
     assert str(s) == \