Thanks Markus. If the header was respected, would you consider it an appropriate mechanism to avoid problems with these proxies? If so I guess I'm wondering whether it'd be prudent to start asking AJAX library authors to include it.
We mobile web folks seem to be seeing this problem sooner than the broader web, but if we can be the "canaries in the coal mine" for you and get preventative measures in place to stop you feeling the pain we've gone through...? Or is there something about AJAX which adding this header in would adversely affect? On Dec 17, 1:53 pm, Markus Peter <w...@spin.de> wrote: > On 17.12.2008, at 11:47, Tom Hume wrote: > > > 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? > > We're sending this header currently on a large German site - > unfortunately, I've not encountered/heard of a transforming proxy yet > which actually respects this header (on the other hand, a proxy which > is coded carefully enough to actually respect the header would usually > also be coded carefully enough not to include any bugs in the > transformation, that's probably why I never encountered a proxy where > the header did actually help to circumvent a problem). > > This issue is worse than it appears on first sight, because many > transforming proxies are actually buggy and cause errors in JavaScript > code, not only in AJAX data requests. So far I've only once managed to > get a mobile carrier to actually fix his bugs. > > Common problems are, that some of them truncate or remove parts of > JavaScript files if they contain strings like "</" or // - even in a > string/regexp! These are obviously oversimplified, regexp-based buggy > comment filters at work. > > That's the reason why we for example use a locally patched version of > jQuery where all occurrences of // and </ in strings are hidden from > those proxies by using <\/ and \/\/ instead, which usually goes > through. I submitted a jQuery feature request months ago where I > requested whether anti-transforming-proxy changes like this could be > done in the official version of jQuery so I need not always patch it > myself, unfortunately it has been ignored so far. > > -- > Markus Peter - w...@spin.de -http://www.spin-ag.de/-http://www.spin.de/ > SPiN AG, Bischof-von-Henle-Str. 2b, 93051 Regensburg, HRB 6295 > Regensburg > Aufsichtsratsvors.: Dr. Christian Kirnberger, Vorstände: F. Rott, P. > Schmid
