Cache-Control HTTP Headers

[psymonic]

Hi all im new to this board, hopefully you will be able to help me out here. My question is what exactly does post-check and pre-check do, I used to know this but i forgot and was stupid enough to not comment my code. If anyone has a definite answer ill be thrilled to hear it because endless searchs on google just couldnt help me out this time.

 

Thanks Guys

Simon

[trq]

My question is what exactly does post-check and pre-check do

 

In what context? I don't see anything about them within the http specs.

[psymonic]

Thanks for replying thorpe, most sites dont use post-check or pre-check. Here is a site which mentions them but doesn't use them.

 

http://www.computec.ch/projekte/httprecon/?s=database&t=head_existing&f=cache-control

 

I think when post-check is set to 0 when you submit a form and then click back you are asked if you want to resubmit the form but when its set to 1 and you submit a form and click back, you go back to the previous page without the form being re submitted.

 

regards

 

I was either post-check or pre-check which does that but i think it was post-check, either way i cant remember at all what the other one does.

[psymonic]

bump

[corbin]

http://www.w3.org/Protocols/rfc2616/rfc2616.html

 

 

I've never heard of Pre-Check, Post-Check.

[psymonic]

It seems no one has, however i have a zend study guide and its used it there however it just says its use for caching, but it doesnt say what.

 

Here in a IE blog they are talking about it.

 

http://blogs.msdn.com/ie/archive/2006/06/01/613132.aspx

 

Also can someone please tell me what setting public and private do in cache-control headers.

 

Thanks

 

 

[The Little Guy]

post the relevant code.

[psymonic]

Its not code its a HTTP Resonce from servers, take this very thread for example i got this responce

 

HTTP/1.x 200 OK

Date: Mon, 10 Nov 2008 16:42:35 GMT

Server: Apache/2.2.8 (EL)

Expires: Mon, 26 Jul 1997 05:00:00 GMT

Cache-Control: private

Pragma: no-cache

Last-Modified: Mon, 10 Nov 2008 16:42:35 GMT

Content-Encoding: gzip

Vary: Accept-Encoding

Keep-Alive: timeout=2, max=100

Connection: Keep-Alive

Transfer-Encoding: chunked

Content-Type: text/html; charset=ISO-8859-1

 

 

im asking what the "private" means in: Cache-Control: private

 

and what would happen if you replace private with public to give: Cache-Control: public

 

also I still need to know what: Cache-Control: post-check: 1, pre-check:1

 

would do.

 

Thanks

[premiso]

Not sure what the private vs public is.

 

I am sure that post-check=1 is that after the page has posted it will check for a new version, where as pre-check=1 the moment you load up that page it checks for a new version.

 

I am not 100% on it, but that makes the most logical sense.

[psymonic]

post-check=1 is that after the page has posted it will check for a new version

 

by posted do u mean a form submitted and i though no-cache made it look for a new version of a page.

 

pre-check=1 the moment you load up that page it checks for a new version.

 

whats the point in looking for a new version if the page already has been loaded.

 

This is really confusing. But thanks for your reply.