Val Petruchek on Web-Development » php

British PHP

val — Thu, 22 Aug 2013 20:02:21 +0000

val — Wed, 03 Aug 2011 09:00:51 +0000

Problem: get number of days in certain month with PHP, if $m – is a month and $y – is an year.

First solution, hacker-style (source):

(31 - (($m - 1) % 7 % 2) - ((($m == 2) << !!($y % 4)))) ?>

This solution doesn’t work properly for years divisible by 100, and non-divisible by 400 (years 1900 and 2100 are not leap)

Second solution, canonical:

date("t",mktime(0,0,0,$m,1,$y));

This solution works only for dates which can be presented as unix timestamps, therefore it’s not good (depends on PHP version and OS.)

Third solution, proper:

function days_in_month($y,$m) {//by val petruchek http://petruchek.com $d = 31; while(!checkdate($m,$d,$y)) $d--; return $d; }

This solution is based on built-in PHP function checkdate() which validates Gregorian date without unix timestamps.

val — Mon, 16 Aug 2010 12:29:51 +0000

Code snippet to output number of bytes with unknown capacity:

function format_filesize($bytes) { if ($bytes == 0) return '0.00 B';


    $s = array('B', 'Kb', 'MB', 'GB', 'TB', 'PB');

    $e = floor(log($bytes)/log(1024));

return sprintf('%.2f '.$s[$e], ($bytes/pow(1024, floor($e)))); }

I don’t know the author of this code.

val — Tue, 10 Aug 2010 06:48:11 +0000

If you have multiple IP addresses and you want to make curl request using non-default IP, you can do it by setting CURLOPT_INTERFACE option:

curl_setopt ($ch, CURLOPT_INTERFACE, '11.22.33.44');

This will work only if you really have that another IP. If you do not have extra IPs, and your only IP is banned already, you need proxies.

If you want to forge your IP address, curl is wrong tool, too.