On Thu, Aug 19, 2010 at 11:52 AM, 49342) mah@everybody.org wrote:
Why is the mobile redirect left to Javascript? Wouldn't it be better for all concerned if the redirect happened before any PHP was loaded?
Wouldn't it be better for those older phones with little memory if the redirect happened in PHP?
Forget memory -- the extra network and processing time involved in fetching an extra complete HTML+CSS+JS version of the page, then throwing it away and fetching another one, is wasteful and annoying even on highly capable phones!
However, we can't just use a User-Agent check in PHP for this, since 90-something percent of the time the PHP scripts are not being executed: the Squid caches respond to most web requests directly.
So what would be required would be some filtering in the caches to check for particular User-Agents or other settings and send them the redirect directly, or send them through to PHP for possible redirection. (Assuming there's no problem with downstream caching, which I think should usually be ok the way we have things marked -- as long as the redirect responses are marked as private-cache or uncacheable.)
A JavaScript hack was quicker to put in place than the cache-level logic, but it was only ever meant as a stopgap.
-- brion vibber (brion @ pobox.com)