Question

What is the MOST correct way according to WP ideology to replace user text in the post content?

Example: I want to replace [b] User Text[/b] To <strong> User text</strong> when text rendered in the browser

Do I need filter?
Do I need Short code API? Or it is perfectly fine to use PHP text replacing functions?

A small code sample will be highly appreciated.

Answer 1

I would use the Shortcode API, then your code for the functions.php would look something like this:

<?php
function shortcode_b_replace($atts, $content = null) {
    return '<strong>'.$content.'</strong>';
}
add_shortcode("b", "shortcode_b_replace");
?>