Problem with kc-access/kc-state cookie, which has more than 4093 bytes

[jangaraj]

As a user I have a lot of assigned groups, so my access token can have more than 4093 bytes. Also, token encryption adds some additional bytes. The problem is that (encrypted) access/refresh token is stored in the cookie (kc-access/kc-state) and the browser may have a problem to write more than 4093 bytes per single cookie - it will result in the infinite loop of issuing access token between keycloak-proxy and IDP because cookie value is not available.

Solution:
If the length of cookie data for the kc-access cookie is larger than 4093 bytes, then set more cookies in the browser, (kc_access, kc-access-1, kc-access-2, ...) so the single cookie will store max 4093 bytes. Also when keycloak-proxy reads kc-access cookie, it will read all cookies with prefix kc-access_ and it will combine them into one value internally.

Reference for the constant 4093 - http://browsercookielimits.squawky.net/.

Any better ideas how to solve this browser cookie size limit?

WIP: master...jangaraj:divided-access-cookie