Measure string size in Bytes in php

Question

I am doing a real estate feed for a portal and it is telling me the max length of a string should be 20,000 bytes (20kb), but I have never run across this before.

How can I measure byte size of a varchar string. So I can then do a while loop to trim it down.

Answer 1

You can use mb_strlen() to get the byte length using a encoding that only have byte-characters, without worring about multibyte or singlebyte strings. For example, as drake127 saids in a comment of mb_strlen, you can use '8bit' encoding:

<?php
    $string = 'Cién ca?ones por banda';
    echo mb_strlen($string, '8bit');
?>

You can have problems using strlen function since php have an option to overload strlen to actually call mb_strlen. See more info about it in http://php.net/manual/en/mbstring.overload.php

For trim the string by byte length without split in middle of a multibyte character you can use:

mb_strcut(string $str, int $start [, int $length [, string $encoding ]] )