metodologias de programação iv - aula 4, secção 1 - suporte para cache no protocolo http

Suporte para cache no protocolo HTTP

2011-2012

Metodologias de Programação IV

GET /tc/home.html HTTP/1.1Host: www.tribunalconstitucional.pt...

HTTP/1.1 200 OKContent-Type: text/html………


HTTP/1.1 200 OKContent-Type: text/html……… + 40.318 bytes


HTTP/1.1 200 OKContent-Type: text/htmlDate: Sun, 16 Oct 2011 16:20:34 GMTLast-Modified: Sun, 16 Oct 2011 07:49:25 GMT… + 40.318 bytes

Last-Modified: Sun, 16 Oct 2011 07:49:26 GMT

Last-Modified: Thu, 29 Jan 2009 02:09:59 GMT

Last-Modified: Wed, 17 Sep 2003 14:46:36 GMT

Last-Modified: Sat, 06 Feb 2010 19:47:46 GMT

Last-Modified: Thu, 02 Jul 2009 02:19:00 GMT

Last-Modified: Wed, 29 Sep 2010 16:33:13 GMT

//v1.7// Flash Player Version Detection// Detect Client Browser type

Cliente Servidor

Cliente Servidor

...

Proxies

HEAD /tc/home.html HTTP/1.1Host: www.tribunalconstitucional.pt...

HTTP/1.1 200 OKContent-Type: text/htmlDate: Sun, 16 Oct 2011 16:20:34 GMTLast-Modified: Sun, 16 Oct 2011 07:49:25 GMT… + 0 bytes

HTTP/1.1 200 OKConnection: Keep-AliveClient-response-num: 1Keep-Alive: timeout=15, max=100Set-Cookie: AF_SID=b672a03f4a0338f035131f6b8034ff33; path=/Date: Sun, 16 Oct 2011 16:20:34 GMTLast-Modified: Sun, 16 Oct 2011 07:49:25 GMTClient-peer: 65.98.99.99.166:80Client-date: Sun, 16 Oct 2011 16:20:34 GMTContent-Type: text/htmlServer: Apache/1.3.41 (Unix) mod_perl/1.31 mod_ssl/2.8.31 OpenSSL/0.9.8e


420 bytes

HTTP/1.1 200 OKConnection: Keep-AliveClient-response-num: 1Keep-Alive: timeout=15, max=100Set-Cookie: AF_SID=b672a03f4a0338f035131f6b8034ff33; path=/Date: Sun, 16 Oct 2011 16:20:34 GMTLast-Modified: Sun, 16 Oct 2011 07:49:25 GMTClient-peer: 65.98.99.99.166:80Client-date: Sun, 16 Oct 2011 16:20:34 GMTContent-Type: text/htmlServer: Apache/1.3.41 (Unix) mod_perl/1.31 mod_ssl/2.8.31 OpenSSL/0.9.8e


420 bytes

Mas se se tiver alterado em relação à cópia em cache…

GET /tc/home.html...

Cliente Servidor

HEAD ...

HTTP/1.1 200 OK

Cliente Servidor

HEAD ...

GET ...

HTTP/1.1 200 OK

HTTP/1.1 200 OK

HTTP/1.1 200 OKDate: Sun, 16 Oct 2011 16:20:34 GMTLast-Modified: Sun, 16 Oct 2011 07:49:25 GMTServer: Apache/1.3.41 (Unix) mod_perl/1.31 mod_ssl/2.8.31 OpenSSL/0.9.8eSet-Cookie: AF_SID=7896d3ac9d40552973a20a4e6cd7ceac; path=/Keep-Alive: timeout=15, max=100Connection: Keep-AliveTransfer-Encoding: chunkedContent-Type: text/html

GET /tc/home.html HTTP/1.1Host: www.tribunalconstitucional.ptIf-Modified-Since: Fri, 14 Oct 2011 19:08:24 GMT...

+ 40.318 bytes

HTTP/1.1 304 Not modifiedConnection: Keep-AliveKeep-Alive: timeout=15, max=99Date: Sun, 16 Oct 2011 18:26:07 GMTClient-peer: 65.98.99.166:80Etag: "e05af-19db-4a4beb1b“Client-date: Sun, 16 Oct 2011 18:26:06 GMTServer: Apache/1.3.41 (Unix) mod_perl/1.31 mod_ssl/2.8.31 OpenSSL/0.9.8e

GET /tc/home.html HTTP/1.1Host: www.tribunalconstitucional.ptIf-Modified-Since: Sun, 16 Oct 2011 07:49:25 GMT...

299 bytes

Cliente Servidor

GET ...

HTTP/1.1 200 OK

HTTP/1.1 304 Not modified

HEAD If-Modified-Since


“HTTP/1.1 implements a more efficient approach to this problem using two new headers: If-Modified-Since and (...)” (p. 58)


http://bit.ly/oNhktc


Ideal para cacheAlternativa p/ cache

Recolha delistas de recursos

Leituras associadas

Web Application Architecture, Second EditionCap. 3: “Birth of the Web: HTTP”, pp. 49-51 e 58-59.

Krishnamurthy, B.; Mogul, J.; Kristol, D. (1999).Key Differences between HTTP/1.0 and HTTP/1.1. In “WWW8 Conference Refereed Papers”, Eighth International World Wide Web Conference, Toronto Convention Centre, Toronto, Canadá,11 a 14 de Maio, 1999.

http://bit.ly/oNhktc

metodologias de programação iv - aula 4, secção 1 - suporte para cache no protocolo http

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