Working with Cookies

Cookies can be accessed in the request and response objects.

Read

To read a cookie:

self.request.cookies # Dictionary of all client-cookies
self.request.cookies.get("Cookie name") # get a specific cookie

Set

Setting a cookie only requires a key and value for the cookie.

To set a cookie:

self.response.set_cookie(
    "Cookie name", 
    "Cookie Value", 
    expires="Optional time string, default: empty", 
    domain="Optional domain, default: empty",
    path="Optional path, default: /")

If the expiration date is not specified then most browsers will treat this as a Session cookie, which lasts until "removed" by the server.

Delete

When a cookie is deleted, its value is replaced with DELETED and the expiration is set to Jan 1st, 1970. Pycnic ignores cookies that contain DELETED in the value.

To delete a cookie:

self.response.delete_cookie("Cookie name")

Full example

from pycnic.core import WSGI, Handler
from pycnic.errors import HTTP_400, HTTP_401

class Login(Handler):

    def get(self):

        sess_id = self.request.cookies.get("session_id")
        return { "session_id":sess_id }

    def post(self):

        username = self.request.data.get("username")
        password = self.request.data.get("password")

        if not username or not password:
            raise HTTP_400("Username and password are required")

        if username != "foo" or password != "foo":
            raise HTTP_401("Username or password are incorrect")

        # Set a session ID for lookup in a DB or memcache
        self.response.set_cookie("session_id", "1234567890abcdefg")
        return { "message":"Logged in" }

class Logout(Handler):

    def post(self):

        if self.request.cookies.get("session_id"):
            # Clear the cookie
            self.response.delete_cookie("session_id")
            return { "message":"Logged out" }

        return {
            "message":"Already logged out",
            "cookies":self.request.cookies
        }

class app(WSGI):
    routes = [
        ("/login", Login()),
        ("/logout", Logout()),
    ]