[erlang-questions] Re: [erlang-questions 29] Re: fun with the new erlang.org!

Raimo Niskanen <>
Thu Mar 31 09:25:09 CEST 2011


On Thu, Mar 31, 2011 at 12:07:55AM +0200, Antoine Koener wrote:
> 
> On Mar 30, 2011, at 13:50 , Steve Vinoski wrote:
> 
> >On Wed, Mar 30, 2011 at 7:41 AM, Raimo Niskanen
> ><> wrote:
> >>On Sat, Mar 26, 2011 at 05:03:56PM +0100, Koener Antoine wrote:
> >>>Cacheability ?
> >>>
> >>>I can reload the page multiples times and still download images.
> >>>
> >>>It seems also that images don't have any 'cache' attributes.
> >>>(I don't recommended using ETags unless you're absolutely sure that
> >>>ETags will be always the
> >>>same on multiple web servers. i.e. some webservers use inode
> >>>information to compute the ETag
> >>>which is different on different servers...thought I don't know how
> >>>erlang-web compute it)
> >>
> >>Please inform a newbie, I just checked HTML4.01 and did not
> >>find any "cache" attribute.
> >
> >He's referring to cache control headers such as Expires, ETag, and
> >Cache-Control. These aren't part of HTML but rather are typically
> >configured for the web server itself. See section 13 of the HTTP 1.1
> >spec:
> >
> >http://www.w3.org/Protocols/rfc2616/rfc2616-sec13.html#sec13
> 
> Exactly Steve,
> 
> Raimo,
> 
> Here's a simple method to determine how 'caching' is handled by the  
> webserver:
> http://www.ircache.net/cgi-bin/cacheability.py?query=http%3A%2F%2Fwww.erlang.org%2Fimages%2Fsearch_bar.jpg&descend=on
> 
> It seems that inets isn't really ideal for serving real web content,  
> because [extracted from the web page]:
> Last-Modified  70 weeks 5 days ago  (Fri, 20 Nov 2009 11:37:29 GMT)  
> validation returned same object
> 
> If-Modified-Since are HTTP headers means:
>  me (web browser talking) please web server give me only content that  
> has changed since this "date", because I don't need to
> retrieve the same content since I already have it...
> 
> Unfortunately inets sends the same content every time a HTTP GET is  
> done, regardless of HTTP headers.
> 
> I hope that this explanation will clarify a bit more.

It seems so, thank you very much. Now I have something to dig into.
Part of the reason why we run Inets on the site is to find out what
problems it has. We supposedly can change web server to Yaws or even
maybe Mochiweb (I do not remember), but would preferably take the
opportunity to fix Inets. I am not on the Inets team so I will take
this to them...

> 
> 
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-- 

/ Raimo Niskanen, Erlang/OTP, Ericsson AB



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