Better cookie handling for Pyramid

cookie.py

"""Cookie utility methods

This module implements a minimal API to consistently and reliably manage
browser cookies. This has two advantages over using the WebOb API:

1. Using a minimal API allows for more simpler calls specifying the intention
   instead of implementation details. For example you must specify a cookie
   must be long-lasting isntead of proving an exact expiration time.
2. The implementation works for views that directly return a response object,
   removing the need to add (multiple) response callbacks.
"""
import datetime


PERSISTENT_COOKIE_TTL = datetime.timedelta(days=365 * 10)


def _update_cookies(request, response):
    for change in request._cookie_changes:
        if change[0] == 'set':
            (name, value, type, parent_domain) = change[1:]
            domain = request.parent_domain if parent_domain else None
            max_age = PERSISTENT_COOKIE_TTL if type == 'persistent' else None
            response.set_cookie(name, value, max_age=max_age, domain=domain)
        elif change[0] == 'delete':
            (name, parent_domain) = change[1:]
            domain = request.parent_domain if parent_domain else None
            response.delete_cookie(name, domain=domain)


def _prepare_request(request):
    if not hasattr(request, '_cookie_changes'):
        request._cookie_changes = []
        request.add_response_callback(_update_cookies)


def set_cookie(request, name, value, type='session', parent_domain=True):
    """Set/update a HTTP cookie.

    :param request: Pyramid request object
    :param str name: cookie name
    :param str value: cookie value
    :param type: the desired cookie type. Must be one of ``session`` to set
       a session cookie or ``persistent`` for long-lasting cookies.
    :param bool parent_domain: If set to True set the cookie for the parent
       domain of the current site.
    """
    _prepare_request(request)
    request._cookie_changes.append(('set', name, value, type, parent_domain))
    request.cookies[name] = value


def delete_cookie(request, name, parent_domain=True):
    """Delete a HTTP cookie.

    :param request: Pyramid request object
    :param str name: cookie name
    :param bool parent_domain: If set to True set the cookie for the parent
       domain of the current site.
    """
    _prepare_request(request)
    request._cookie_changes.append(('delete', name, parent_domain))


__all__ = ['delete_cookie', 'set_cookie']