Modify headers in Pylons using Middleware

Question

Hi all,

I'm trying to modify a header using Middleware in Pylons to make my application RESTful, basically, if the user request "application/json" via GET that is what he get back.

The question I have is, the variable headers is basically a long list. Looking something like this:

[('Content-Type', 'text/html; charset=utf-8'), ('Pragma', 'no-cache'), ('Cache-Control', 'no-cache'), ('Content-Length','20'), ('Content-Encoding', 'gzip')]

Now, I'm looking to just modify the value based on the request - but are these positions fixed? Will 'Content-Type' always be position headers[0][0]?

Best Regards,

Anders