I have a general query around AJAX; apologies in advance if this isn't on-topic for the list, but I figured you guys are experts and would be a good place to start :) If there's a better place for me to post this, please do let me know.
One of the issues we're battling with in the world of mobile is that of transforming proxies: bits of network infrastructure which are typically installed into mobile operator networks and alter the content flowing through them. In the past there have been deployments of this kit which adversely affected a whole load of mobile services (notably by Vodafone here in the UK) and broke them. There are several efforts running concurrently to try and prevent this happening in future[1]. However, it looks to me like the problem is starting to spread beyond the mobile web. Vodafone, for instance, are running a minify proxy on their web traffic: http://www.orbific.com/weblog/2008/10/vodafone-proxy-breaks-some-javascript.html So for the full-fat web, transformation looks like it's becoming an issue; and we suspect that it might be a particular problem for AJAX requests which might be passing around fragments of markup or structured data, and can't be programmatically distinguished from regular web requests. There is a mechanism in HTTP for clients and servers to request that transformation not occur on their content, the "Cache-Control: no- transform" header. Transcoding proxies should respect this; some deployments don't, currently. There are efforts ongoing to put pressure on ISPs to either drop transcoding altogether, or at least configure it responsibly. I'd be interested in hearing any thoughts on technical solutions to this problem; would it, for instance, be reasonable and/or pragmatically defensive to include "Cache-control: no-transform" by default on HTTP requests triggered by AJAX clients or servers? Thanks Tom [1] See http://www.w3.org/TR/ct-guidelines/ and http://wurfl.sourceforge.net/manifesto/
