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<TITLE>RE: [squid-dev] [RFC] client header mangling</TITLE>
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<P DIR=LTR><SPAN LANG="en-us"><FONT FACE="Calibri">I am trying to understand so bear with me couple seconds.</FONT></SPAN><SPAN LANG="en-us"></SPAN></P>
<P DIR=LTR><SPAN LANG="en-us"><FONT FACE="Calibri">I have seen that there are pages</FONT></SPAN><SPAN LANG="en-us"><FONT FACE="Calibri">\servers</FONT></SPAN><SPAN LANG="en-us"><FONT FACE="Calibri"> which doesn't state about the User-Agent in the Vary response while still taking it into accou</FONT></SPAN><SPAN LANG="en-us"><FONT FACE="Calibri">n</FONT></SPAN><SPAN LANG="en-us"><FONT FACE="Calibri">t.</FONT></SPAN></P>
<P DIR=LTR><SPAN LANG="en-us"></SPAN></P>
<P DIR=LTR><SPAN LANG="en-us"><FONT FACE="Calibri">The caching side of the picture</FONT></SPAN><SPAN LANG="en-us"> <FONT FACE="Calibri">is storing</FONT></SPAN><SPAN LANG="en-us"><FONT FACE="Calibri"> an</FONT></SPAN><SPAN LANG="en-us"><FONT FACE="Calibri"> object which will never be served.</FONT></SPAN></P>
<P DIR=LTR><SPAN LANG="en-us"><FONT FACE="Calibri">The HIT ratio is a whole other story of the picture.</FONT></SPAN></P>
<P DIR=LTR><SPAN LANG="en-us"><FONT FACE="Calibri">Since I am not inside the code but I do try to understand, currently what happens?</FONT></SPAN></P>
<P DIR=LTR><SPAN LANG="en-us"><FONT FACE="Calibri">How many lookups are done for</FONT></SPAN><SPAN LANG="en-us"><FONT FACE="Calibri">\per</FONT></SPAN><SPAN LANG="en-us"><FONT FACE="Calibri"> a request? D</FONT></SPAN><SPAN LANG="en-us"><FONT FACE="Calibri">o we run a</FONT></SPAN><SPAN LANG="en-us"><FONT FACE="Calibri">n object</FONT></SPAN><SPAN LANG="en-us"><FONT FACE="Calibri"> lookup after the response headers was received from the server?</FONT></SPAN></P>
<P DIR=LTR><SPAN LANG="en-us"><FONT FACE="Calibri">Can we predict a Vary object based on the request only?(I assume that it will be an estimated and not absolute</FONT></SPAN><SPAN LANG="en-us"> <FONT FACE="Calibri">certainty</FONT></SPAN><SPAN LANG="en-us"><FONT FACE="Calibri"> if at all)</FONT></SPAN><SPAN LANG="en-us"></SPAN></P>
<P DIR=LTR><SPAN LANG="en-us"><FONT FACE="Calibri">Also let say we have a 1k page ahead, would we want it to be fetched from disk\ram store rathe</FONT></SPAN><SPAN LANG="en-us"><FONT FACE="Calibri">r</FONT></SPAN><SPAN LANG="en-us"><FONT FACE="Calibri"> then from</FONT></SPAN><SPAN LANG="en-us"><FONT FACE="Calibri"> the origin server after we told it we want the object?</FONT></SPAN><SPAN LANG="en-us"></SPAN></P>
<P DIR=LTR><SPAN LANG="en-us"><FONT FACE="Calibri">I am almost sure that lowering the disk and ram stored objects should be a goal by itself if we cannot</FONT></SPAN><SPAN LANG="en-us"> <FONT FACE="Calibri">"</FONT></SPAN><SPAN LANG="en-us"><FONT FACE="Calibri">dig</FONT></SPAN><SPAN LANG="en-us"><FONT FACE="Calibri">"</FONT></SPAN><SPAN LANG="en-us"><FONT FACE="Calibri"> them up from ram or disk later</FONT></SPAN><SPAN LANG="en-us"><FONT FACE="Calibri"> for any use</FONT></SPAN><SPAN LANG="en-us"><FONT FACE="Calibri">.</FONT></SPAN></P>
<P DIR=LTR><SPAN LANG="en-us"></SPAN></P>
<P DIR=LTR><SPAN LANG="en-us"><FONT FACE="Calibri">A request_header_replace can work only for "generic" ones such as without a language preference such as "br" added to some requests by</FONT></SPAN><SPAN LANG="en-us"> <FONT FACE="Calibri">browser add-ons.</FONT></SPAN></P>
<P DIR=LTR><SPAN LANG="en-us"><FONT FACE="Calibri">Now a step further, I can write a tiny</FONT></SPAN><SPAN LANG="en-us"><FONT FACE="Calibri"> ICAP service that will "handle" common Vary headers from FireFox and other browsers</FONT></SPAN><SPAN LANG="en-us"><FONT FACE="Calibri"> to test how it affects caches in general.</FONT></SPAN></P>
<P DIR=LTR><SPAN LANG="en-us"></SPAN></P>
<P DIR=LTR><SPAN LANG="en-us"><FONT FACE="Calibri">Eliezer</FONT></SPAN></P>
<P DIR=LTR><SPAN LANG="en-us"></SPAN></P>
<P DIR=LTR><SPAN LANG="en-us"></SPAN><SPAN LANG="en-us"></SPAN><SPAN LANG="en-us"></SPAN><SPAN LANG="he"><FONT FACE="Arial"><SPAN DIR=RTL>----</SPAN></FONT></SPAN></P>
<P DIR=LTR><SPAN LANG="en-us"></SPAN><SPAN LANG="he-il"><FONT FACE="Calibri">Eliezer Croitoru</FONT></SPAN></P>
<P DIR=LTR><SPAN LANG="he-il"><FONT FACE="Calibri">Linux System Administrator</FONT></SPAN></P>
<P DIR=LTR><SPAN LANG="he-il"><FONT FACE="Calibri">Mobile: +972-5-28704261</FONT></SPAN></P>
<P DIR=LTR><SPAN LANG="he-il"><FONT FACE="Calibri">Email: eliezer@ngtech.co.il</FONT></SPAN></P>
<P DIR=LTR><SPAN LANG="en-us"></SPAN><SPAN LANG="en-us"></SPAN><SPAN LANG="en-us"></SPAN><SPAN LANG="he"></SPAN></P>
<P DIR=LTR><SPAN LANG="en-us"></SPAN><SPAN LANG="he-il"></SPAN></P>
<P DIR=LTR><SPAN LANG="en-us"><FONT FACE="Calibri">-----Original Message-----<BR>
From: squid-dev [<A HREF="mailto:squid-dev-bounces@lists.squid-cache.org">mailto:squid-dev-bounces@lists.squid-cache.org</A>] On Behalf Of Amos Jeffries<BR>
Sent: Tuesday, June 7, 2016 2:10 PM<BR>
To: Squid Developers<BR>
Subject: [squid-dev] [RFC] client header mangling</FONT></SPAN><SPAN LANG="en-us"></SPAN></P>
<P DIR=LTR><SPAN LANG="en-us"><FONT FACE="Calibri">I've been looking at ways to resolve the long Vary discussion going on in squid-users with a patch that we can accept into mainline. What they (joe and Yuri) have at present works, but only with extra request_header_replace config preventing integrity problems.</FONT></SPAN></P>
<P DIR=LTR><SPAN LANG="en-us"></SPAN><SPAN LANG="en-us"></SPAN><SPAN LANG="en-us"></SPAN><SPAN LANG="he"></SPAN></P>
<P DIR=LTR><SPAN LANG="en-us"><FONT FACE="Calibri">One way to make useful progress would be to finally add the recurring request for request_header_access/replace to work on client messages in a pre-cache doCallouts hook rather than only a post-cache hook.</FONT></SPAN></P>
<P DIR=LTR><SPAN LANG="en-us"></SPAN><SPAN LANG="en-us"></SPAN><SPAN LANG="en-us"></SPAN><SPAN LANG="he"></SPAN></P>
<P DIR=LTR><SPAN LANG="en-us"><FONT FACE="Calibri">I am imagining this being done on the adapted request headers after ICAP, eCAP and URL-rewrite have all done their things. And using the same request_header_* directive ACL lists as for outbound traffic.</FONT></SPAN></P>
<P DIR=LTR><SPAN LANG="en-us"></SPAN><SPAN LANG="en-us"></SPAN><SPAN LANG="en-us"></SPAN><SPAN LANG="he"></SPAN></P>
<P DIR=LTR><SPAN LANG="en-us"><FONT FACE="Calibri">Any alternative ideas or objections?</FONT></SPAN></P>
<P DIR=LTR><SPAN LANG="en-us"></SPAN><SPAN LANG="en-us"></SPAN><SPAN LANG="en-us"></SPAN><SPAN LANG="he"></SPAN></P>
<P DIR=LTR><SPAN LANG="en-us"><FONT FACE="Calibri">Amos</FONT></SPAN></P>
<P DIR=LTR><SPAN LANG="en-us"></SPAN><SPAN LANG="en-us"></SPAN><SPAN LANG="en-us"></SPAN><SPAN LANG="he"></SPAN></P>
<P DIR=LTR><SPAN LANG="he"><FONT FACE="Arial"><SPAN DIR=RTL>_______________________________________________</SPAN></FONT></SPAN></P>
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