From:  Valentin Gosu <valentin.gosu@gmail.com>
Date:  19 Dec 2015 06:54:41 Hong Kong Time
Newsgroup:  news.mozilla.org/mozilla.dev.tech.network
Subject:  

Re: devtools re-fetching problem

NNTP-Posting-Host:  63.245.214.181

On 18 December 2015 at 22:56, Tom Tromey  wrote:

> I mentioned this on #necko the other day.
>
> We've had a "re-fetching" problem in devtools for a while now.
>
> The basic issue is that the platform drops the original text of some
> things, like style sheets.  (Instead just the parsed form is preserved.)
>
> So, in order to make some tools work with the source text, devtools
> re-fetches the sources.  However, this is sub-optimal -- maybe the
> sources have changed on the server, leading to confusing results.
>
> We were wondering if there was some way we could solve this problem.
>
> One idea we had is to always cache these things, in a way that would let
> the devtools retrieve them.  Is this possible?
>
> Or ... some other idea here.
>
>
Is the problem that we're not caching these resources? Maybe because of the
response headers?
Or is there another reason that we can't use the previously downloaded
files?


>
> On irc jduell mentioned:
>
>  tromey: I think you want to set the LOAD_ONLY_FROM_CACHE loadflag
> on
>          your network request
>
> ... which isn't really want we want, I think (but which in context made
> perfect sense) --


nsIRequest::LOAD_FROM_CACHE should disable revalidation, and give you what
is in the cache. It falls back on the network if the resource is missing,
but if you combine it with nsICachingChannel::LOAD_ONLY_FROM_CACHE, it
would fail it the resource wasn't cached.

Of course, if the file is not cached at all, this wouldn't work, and a
re-fetch would be necessary :)


> but maybe a Plan B would be to use that to at least
> inform users: "hey, devtools had to re-fetch this, be warned".
>
>