How can i cache the result of rand()? - php

Question

I want to cache the result of rand() for 5 minutes.
<?php
$sec = 300;
$expires = gmdate("D, d M Y H:i:s", time() + $sec) . " GMT";
header("Expires: $expires");
header("Pragma: cache");
header("Cache-Control: max-age=$sec");
echo "Test " . rand(1, 10);
Unfortunately, i don't know why my code doesn't work. Everytime i call the php file in my browser the random number is different.
Does anybody has an idea what the problem is?
Edit:
The headers are sent correctly, but everytime I reload the page, the Expires header changes.
When i print $_SERVER, The HTTP_CACHE_CONTROL header says no-cache.
Could that be the problem?

Answer 1

Ok, everyone here suggesting alternatives, including javascript, cookies, etc but that does NOT answer the question.
The question is to cache using headers for that explicitly a 304 NOT Modified response exists...
<?php
$sec = 300;
if(isset($_SERVER['HTTP_IF_MODIFIED_SINCE']))
{
$if_modified=time($_SERVER['HTTP_IF_MODIFIED_SINCE']);
if($if_modified>time()-$sec)
{
Header("HTTP/1.1 304 Not Modified");
exit();
}
}
$expires = gmdate("D, d M Y H:i:s", time() + $sec) .' '. date_default_timezone_get();
$modified= gmdate("D, d M Y H:i:s", time()) . ' '.date_default_timezone_get();
header("Expires: $expires");
header("Last-Modified: $modified");
header("Pragma: cache");
header("Cache-Control: max-age=$sec");
echo "Test " . rand(1, 10);
There you go.
Caching random numbers with headers.

Answer 2

I want to cache the result of rand() for 5 minutes.It can be possible throw javascript code. But it store in cookie
// this fun call after every 5 miniute
setInterval(function(){
generate_and_cookie_random_fun();
}, 5000);
// this fun generate random number and sotre it to cookie
function generate_and_cookie_random_fun(){
var random_number = Math.floor(Math.random() * 6) + 1 ;
setCookie('name_of_cookie',random_number ,7); // here 7 mean seven days
}
// below code for cookie
function setCookie(name,value,days) {
var expires = "";
if (days) {
var date = new Date();
date.setTime(date.getTime() + (days*24*60*60*1000));
expires = "; expires=" + date.toUTCString();
}
document.cookie = name + "=" + (value || "") + expires + "; path=/";
}
function getCookie(name) {
var nameEQ = name + "=";
var ca = document.cookie.split(';');
for(var i=0;i < ca.length;i++) {
var c = ca[i];
while (c.charAt(0)==' ') c = c.substring(1,c.length);
if (c.indexOf(nameEQ) == 0) return c.substring(nameEQ.length,c.length);
}
return null;
}
function eraseCookie(name) {
document.cookie = name+'=; Max-Age=-99999999;';
}

Answer 3

The simple way is to store it into cookie and check that if cookie exists to show the stored number, otherwise generate new.
Something like this:
<?php
setcookie("random_number", rand(1, 10), time() + 300);
if(isset($_COOKIE['random_number'])) {
echo $_COOKIE['random_number'];
} else {
setcookie("random_number", rand(1, 10), time() + 300);
}