Akceleracni proxy

[Pavel Kankovsky]

On Sat, 28 Jun 2003, EHP wrote:

> Hlavicka pri primem dotazu do apache:
> GET / HTTP/1.1
> Host: www.domena.cz
> 
> HTTP/1.1 200 OK
> Date: Sat, 28 Jun 2003 15:33:45 GMT
> Server: Apache/1.3.27 (Unix)  (Red-Hat/Linux) PHP/4.2.3
> X-Powered-By: PHP/4.2.3
> X-Accelerated-By: PHPA/1.3.3r2
> Set-Cookie: PHPSESSID=fddb4286011860e888a85330da50c6f3; path=/
> Expires: Sat, 28 Jun 2003 16:34:15 GMT
> Cache-Control: store, cache
> Pragma: cache
> Last-Modified: Sat, 28 Jun 2003 16:33:45 GMT
> Transfer-Encoding: chunked
> Content-Type: text/html
> 
> 
> Hlavicka pri dotazu pres squid:
> GET / HTTP/1.1
> Host: www.domena.cz
> 
> HTTP/1.0 200 OK
> Date: Sat, 28 Jun 2003 15:26:37 GMT
> Server: Apache/1.3.27 (Unix)  (Red-Hat/Linux) PHP/4.2.3
> X-Powered-By: PHP/4.2.3
> X-Accelerated-By: PHPA/1.3.3r2
> Expires: Sat, 28 Jun 2003 16:27:07 GMT
> Cache-Control: store, cache
> Pragma: cache
> Last-Modified: Sat, 28 Jun 2003 16:26:37 GMT
> Content-Type: text/html
> Age: 740
> X-Cache: HIT from domena.cz
> Connection: close

Shledavam tady nekolik podezrelych skutecnosti:

1. Mezi casovymi udaji z obou odpovedi je znacny rozdil (i po zapocteni
   +740 s...viz bod 2) a Squid je znacne pozadu (nebo naopak jde dost 
   napred). Jak jsou nastavene hodiny na obou pocitacich?

2. Hlavicka Age ukazuje, ze stranka je v kesi Squidu uz 740 sekund,
   cili 12 m 20 s. To rozhodne nevypada jako "nekolik dni stara odpoved".
   Na druhou stranu je to mnohem vic nez 30 sekund tvoricich rozdil mezi
   Expires a Date. Urcite nemate Squid nakonfigurovany s nejakou minimalni
   dobou, po kterou drzi udaje v kesi bez ohledu na okolnosti?

3. Odpoved Squidu je HTTP 1.0, ackoli dotaz i "originalni" odpoved
   od Apache je 1.1.

4. Proc vubec nechavate ty stranky ukladat do kese, kdyz do nich
   strkate cookie?

5. Hlavicka Cache-Control zna podle RFC 2616 direktivy no-store a
   no-cache, ale nikoli jejich "antonyma" store a cache. Totez plati
   pro Pragma: cache.


--Pavel Kankovsky aka Peak  [ Boycott Microsoft--http://www.vcnet.com/bms ]
"Resistance is futile. Open your source code and prepare for assimilation."