If-modified-since HTTP compliant!

[Chris]

Hi,

is there a HTTP-compliant implementation of If-Modified-Since-, If-Match,
If-None-Match, If-Range and so on?

I want my PHP-script to act exactly as if it was a static HTML-page
delivered directly from Apache.

I think this isn't easy to implement, especially if you take also weak and
strong validators into account.

Chris

[Janwillem Borleffs]

Chris wrote:

is there a HTTP-compliant implementation of If-Modified-Since-,
If-Match, If-None-Match, If-Range and so on?

I want my PHP-script to act exactly as if it was a static HTML-page
delivered directly from Apache.

I think this isn't easy to implement, especially if you take also
weak and strong validators into account.

To implement support for the if-modified-since header and when running
Apache, you would put something like the following on top of your page:

$request = array_change_key_case(apache_request_headers(), CASE_LOWER);
if (isset($request['if-modified-since'])) {
if (filemtime(__FILE__) > strtotime($request['if-modified-since'])) {
header("HTTP/1.1 304 Not Modified");
exit;
}
}

The key here is the apache_request_headers() function, which is used to
parse the request headers.
JW

[Chris]

On Sun, 7 Aug 2005 14:07:23 +0200 Janwillem Borleffs wrote :

To implement support for the if-modified-since header and when running
Apache, you would put something like the following on top of your page:

Thank you, Janwillem.

There are many examples codes like you posted on the net. They'll probably
all work. The problem is to find a *HTTP-compliant* implementation.

- Chris

[Janwillem Borleffs]

Chris wrote:

There are many examples codes like you posted on the net. They'll
probably all work. The problem is to find a *HTTP-compliant*
implementation.

Then I'm not sure what you mean with HTTP-compliant. IMO, HTTP compliancy is
enforced by sending a response according to HTTP specifications for a
specific header.

If you mean that you would like to have an implementation which works for
all webservers, basically the only difference will be the way you retrieve
the request headers and you will have to test this for each individual
webserver.
JW

[Chris]

On Sun, 7 Aug 2005 15:25:50 +0200 Janwillem Borleffs wrote :

Then I'm not sure what you mean with HTTP-compliant. IMO, HTTP compliancy
is enforced by sending a response according to HTTP specifications for a
specific header.

Yes, that's it. Have a look at the HTTP-RFC, it's a bit more complicated.
There's not only the If-Modified-Since header, but there's also a
If-Match-, If-None-Match-, If-Range-, Vary-, and other headers.

[Janwillem Borleffs]

Chris wrote:

Yes, that's it. Have a look at the HTTP-RFC, it's a bit more
complicated. There's not only the If-Modified-Since header, but
there's also a If-Match-, If-None-Match-, If-Range-, Vary-, and other
headers.

I know, I used the if-modified-since header as an example. What you should
do is determine which headers you want to implement support for, implement
them according to specifications and collect them in a class or a set of
functions. Developers tend to write code only for what they need and most
HTTP headers are seldom used on the PHP programming level
JW

..

[Chris]

On Sun, 7 Aug 2005 16:27:15 +0200 Janwillem Borleffs wrote :

I know, I used the if-modified-since header as an example. What you
should do is determine which headers you want to implement support for,
implement them according to specifications

Sure, I could do that. But my question is still, if someone knows a
finished and ready-to-use code.