Question

I wan’t developers who embed my webapp to be able to pass a param in the url like ?style=dark which will alter the css accordingly. Is there a better way to keep this setting as the user navigates than appending ?style=dark to all links?

I’ve considered cookies etc. but if one user is viewing two pages which embed my app with different themes then one will override the other.

I’m using Python/Django.

Answer 1

If you neither want to use Cookies nor Sessions and do not want to embed it into URLs, the only alternatives which comes to my mind are:

First the most generic: Use a dummy domain in front. Instead of http://www.example.com use h**p://THEME.example.com/PATH. This even works for HTTPS if you own a wildcard SSL for *.example.com.

A second variant would be to create a Basic-Auth-Handler which uses the Theme as the username with a dummy password. The URL then can look like:

h**p://[e-mail]/PATH

However I am NOT sure what happens if a user connects to the same site with two different themes in the Basic-Auth-case. Also it is somewhat tricky to make the site available for search engines if it is behind an authentication handler. This is because you MUST have an auth-handler today to circumvent the Anti-Phishing-protection in modern browsers.

Note that with both methods you can only have one parameter easily. The password does not count and there are browsers out there which do not accept a wildcard SSL cert *.example.com for PARAM1.PARAM2.example.com.