sessions: addition of KVSession interface

[drjova]

Signed-off-by: Harris Tzovanakis me@drjova.com

Closes #289.

[drjova]

@slint updated

[kpsherva]

small impact: IMO the name indicates that we store sessions for anonymous. I would suggest KVSessionInterfaceStoreAuthenticated, also is it possible to test it?

[diegodelemos]

Working using latest cookiecutter-invenio-instance:

~/invenio-accounts $ git diff
diff --git a/setup.py b/setup.py
index 0eed598..81e41f9 100644
--- a/setup.py
+++ b/setup.py
@@ -75,7 +75,7 @@ install_requires = [
      'email-validator>=1.0.5',
      'future>=0.16.0',
      'invenio-base>=1.2.2',
-    'invenio-i18n>=1.2.0',
+    'invenio-i18n<1.2.0,>=1.1.1',
      'invenio-celery>=1.1.2',
      'invenio-rest>=1.1.3',
      'maxminddb-geolite2>=2017.404',
~/invenio-accounts $ cd ../ && cookiecutter cookiecutter-invenio-instance
$ cd my-site
$ cat my_site/config.py
...
# Sessions
# ========
#: Whether the instance should use SameSite cookies to store client sessions.
SESSION_COOKIE_SAMESITE = 'Strict'
...
$ ./scripts/bootstrap
$ ./scripts/setup
$ pipenv install ../invenio-accounts # the dev version
$ pip env shell
$ pip uninstall flask-kvsession -y
$ pip show flask-kvsession-invenio 
Name: Flask-KVSession-Invenio
Version: 0.6.3
...
$ ./scripts/server

Note: Invenio-i18n version needs to be changed because Invenio 3.2.1 doesn't support it, but this doesn't change anything regarding Flask-KVSession integration

---

We need to:

• Decide what are we going to put as the default value for SameSite cookies on sessions, in the past, we have been always choosing the most secure defaults but I am not sure for this case.
• Address Karolina's message:
  • Regarding the naming, I agree with her.
  • Regarding the tests, should I go ahead and write them?

CC @ppanero.