generate config: don't filter unsupported pagespeed directives in .pyconf files

[oschaaf]

This allows templates to declare a list of unsupported pagespeed directives.
These will be filtered out, and a warning will be written for them.

[jeffkaufman]

Mostly good, but I don't like the global variable hack. What if we moved the 'unsupported' check into nginx's write_pagespeed_open?

[oschaaf]

@jeffkaufman: "What if we moved the 'unsupported' check into nginx's write_pagespeed_open"

That is the way I tackled the problem initially, I have reverted the my last commit so you can judge it.
I thought, that adding a global might be worth it, as that would prevent every template from having to reimplement this filter functionality

[jeffkaufman]

prevent every template from having to reimplemented this filter functionality

The code that would be duplicated across templates seems to be just:

if key.lower() in map(str.lower,pagespeed_unsupported):
    warnings.warn("%s not supported, skipping" % key)
    continue

we could pull the tricky part out into a function:

def check_unsupported(unsupported_directives, directive):
     return directive.lower() in map(str.lower, usupported_directives)

I could go either way on that. But I think the global-variable approach is too complicated and doesn't let "what does nginx support" be entirely up to nginx.conf.template.

[oschaaf]

@jeffkaufman
That makes sense to me

re: "I could go either way on that."
I think I am fine with it the way it is now.

[jeffkaufman]

LGTM