Fastest way to get random php number?

Question

Am I trying to prevent caching by adding '? t = 'to the end of my JS files. What is the fastest way to get such a number? time () or rand () or something else?

Answer 1

time () and mt_rand () are quite similar in terms of efficiency in PHP - you choose one or the other based on what factors you need:

• Just hard to guess: use mt_rand () (e.g. generating a usage salt)
• Get a unique identifier that is hard to guess: use mt_rand (1, 931415926536); (e.g. generating a session id)
• (obvious) save entries: use time () (e.g. prevent caching, logs, etc.)

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(mt_rand() 4 , rand())

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Answer 2

, () .

Answer 3

, - , , HTTP-, URL-. PHP:

<?php
header("Cache-Control: no-cache, must-revalidate"); // HTTP/1.1
header("Expires: Sat, 26 Jul 1997 05:00:00 GMT"); // Date in the past
?>

.htaccess apache ( -):

<FilesMatch "\.js$">
Header set Cache-Control "no-cache, must-revalidate"
Header set Expires "Sat, 26 Jul 1997 05:00:00 GMT"
</FilesMatch>

Answer 4

Try:

'?t=' . mt_rand(time());

Answer 5

rand(), mt_rand().

It uses a well-known random number generator using Mersenne Twister , which will generate random numbers four times faster than the average libc rand () provides.

Answer 6

srand(time());
echo '?t=' . rand();