Re: [PHP] Force refresh of graphic - how?
<[EMAIL PROTECTED]> wrote in message news:[EMAIL PROTECTED] > Thanks for your suggestions. I had been thinking that it > must be the URL that was causing the caching (same URL, > same thing, right? Sounds good...), so I was planning > on trying something along the lines of what you suggest. > But I was thinking, why a random number? Why not just > append the current time value? (time()) ... it won't be > the same for any single user more than once, so that > should force the re-fetch of the graphic, just like the > random would. Shouldn't this work too? (Said he without > having time to test either approach!) Yes, that should work. Steve -- PHP General Mailing List (http://www.php.net/) To unsubscribe, visit: http://www.php.net/unsub.php
Re: [PHP] Force refresh of graphic - how?
Ok, thanks for the tip :)
Justin
on 13/03/03 7:53 PM, Ernest E Vogelsinger ([EMAIL PROTECTED]) wrote:
> At 23:33 12.03.2003, Justin French said:
> [snip]
>> Put this code in your shared library of functions (adapted from manual,
>> untested):
>> > function randNumber($min=1000,$max=9)
>> {
>> // build a seed
>> list($usec, $sec) = explode(' ', microtime());
>> $seed = (float) $sec + ((float) $usec * 10);
>>
>> // seed random generator
>> srand($seed);
>>
>> // return random number
>> return rand($min,$max);
>> }
>> ?>
> [snip]
>
> May I?
>
> It's usually not a good idea to re-seed the randum number generator during
> a single script instance, as this might use the same seed more than once,
> resulting in the identical random sequence...
>
> To avoid reseeding, you could e.g. use a static variable in your
> randNumber() function:
>
> function randNumber($min=1000,$max=9)
> {
> static $is_seeded = false;
> if (!$is_seeded) {
> $is_seeded = true;
> // build a seed
> list($usec, $sec) = explode(' ', microtime());
> $seed = (float) $sec + ((float) $usec * 10);
> // seed random generator
> srand($seed);
> }
> ...
>
> I prefer to add a string generated by uniqid(), such as
>
>
> uniqid() uses the entropy generated by the opsys random device (if
> available) in an attempt to make this truly random.
>
>
>
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Re: [PHP] Force refresh of graphic - how?
Thanks for your suggestions. I had been thinking that it must be the URL that was causing the caching (same URL, same thing, right? Sounds good...), so I was planning on trying something along the lines of what you suggest. But I was thinking, why a random number? Why not just append the current time value? (time()) ... it won't be the same for any single user more than once, so that should force the re-fetch of the graphic, just like the random would. Shouldn't this work too? (Said he without having time to test either approach!) - Mark --- Mark Wilson, Computer Programming Unlimited Web: http://www.cpuworks.com/ Email: [EMAIL PROTECTED] Our motto: "Getting the Job Done" -- PHP General Mailing List (http://www.php.net/) To unsubscribe, visit: http://www.php.net/unsub.php
Re: [PHP] Force refresh of graphic - how?
At 23:33 12.03.2003, Justin French said:
[snip]
>Put this code in your shared library of functions (adapted from manual,
>untested):
>function randNumber($min=1000,$max=9)
>{
>// build a seed
>list($usec, $sec) = explode(' ', microtime());
>$seed = (float) $sec + ((float) $usec * 10);
>
>// seed random generator
>srand($seed);
>
>// return random number
>return rand($min,$max);
>}
>?>
[snip]
May I?
It's usually not a good idea to re-seed the randum number generator during
a single script instance, as this might use the same seed more than once,
resulting in the identical random sequence...
To avoid reseeding, you could e.g. use a static variable in your
randNumber() function:
function randNumber($min=1000,$max=9)
{
static $is_seeded = false;
if (!$is_seeded) {
$is_seeded = true;
// build a seed
list($usec, $sec) = explode(' ', microtime());
$seed = (float) $sec + ((float) $usec * 10);
// seed random generator
srand($seed);
}
...
I prefer to add a string generated by uniqid(), such as
uniqid() uses the entropy generated by the opsys random device (if
available) in an attempt to make this truly random.
--
>O Ernest E. Vogelsinger
(\)ICQ #13394035
^ http://www.vogelsinger.at/
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Re: [PHP] Force refresh of graphic - how?
It's caching an image based on it's URL, so clearly, the browser is not looking for another pic if the URL is the same, based on the settings you have for caching in your browser. Other people's results will vary. The no cache headers on the images SHOULD help, as would no cache headers on the calling HTML file, but the easiest way is to get a random number, and tap it onto the query string: Put this code in your shared library of functions (adapted from manual, untested): Then when calling your images, call them with a random number attached: The browser will (mostly) see a "new" image URL and look at the server for it, rather than looking in cache. Justin on 13/03/03 3:49 AM, Mark Wilson ([EMAIL PROTECTED]) wrote: > I have a PHP page which in turn calls an image-creating PHP program, > like so: > ...(calling page: mypage.php).. > > > > > > > > makepic.php does database lookups using the values of opt1 and opt2, > then creates a graphic (PNG) using that data and returns the graphic. > So far, so good... but the graphic is being cached, so the data is not > always up-to-date, unless I do a shift-reload of the calling page. > I tried adding a "pragma nocache" line to the HEAD of mypage.php, > but that had no effect. I don't want to tell my users to always do a > shift-reload - how can I force either mypage.php to not cache > the graphic, or get makepic.php's output to not be cached > Thanks... replies to [EMAIL PROTECTED] > > -- PHP General Mailing List (http://www.php.net/) To unsubscribe, visit: http://www.php.net/unsub.php
Re: [PHP] Force refresh of graphic - how?
You can use the meta tags to do a refresh of the browser page... example: after content you add the seconds of delay before refresh... More info on the meta tag: http://www.xs4all.nl/~dimaroan/htl/index.html -- Ray On Wed, 2003-03-12 at 09:49, Mark Wilson wrote: > I have a PHP page which in turn calls an image-creating PHP program, > like so: > ...(calling page: mypage.php).. > > > > > > > > makepic.php does database lookups using the values of opt1 and opt2, > then creates a graphic (PNG) using that data and returns the graphic. > So far, so good... but the graphic is being cached, so the data is not > always up-to-date, unless I do a shift-reload of the calling page. > I tried adding a "pragma nocache" line to the HEAD of mypage.php, > but that had no effect. I don't want to tell my users to always do a > shift-reload - how can I force either mypage.php to not cache > the graphic, or get makepic.php's output to not be cached > Thanks... replies to [EMAIL PROTECTED] > > -- PHP General Mailing List (http://www.php.net/) To unsubscribe, visit: http://www.php.net/unsub.php
[PHP] Force refresh of graphic - how?
I have a PHP page which in turn calls an image-creating PHP program, like so: ...(calling page: mypage.php).. makepic.php does database lookups using the values of opt1 and opt2, then creates a graphic (PNG) using that data and returns the graphic. So far, so good... but the graphic is being cached, so the data is not always up-to-date, unless I do a shift-reload of the calling page. I tried adding a "pragma nocache" line to the HEAD of mypage.php, but that had no effect. I don't want to tell my users to always do a shift-reload - how can I force either mypage.php to not cache the graphic, or get makepic.php's output to not be cached Thanks... replies to [EMAIL PROTECTED] -- PHP General Mailing List (http://www.php.net/) To unsubscribe, visit: http://www.php.net/unsub.php
