I'm with the code:
function addhttp($url){
if(!preg_match('~^(http)s?://~i', $url)){
$url = 'http://'.$url;
}
return $url;
}
It will add HTTP if the URL you entered does not contain it, but what I'm in doubt is the ~ issue you have at the beginning and then at the end ~ i . I would like to know what this is for.
PCRE (Perl Compatible Regular Expressions) regular expressions require delimiters that are a pair of non-alphanumeric characters where one is at the beginning and another at the end. It is also common to use the / bar as a delimiter if your regex needs to capture some you need to escape it.
'~^(http)s?://~i <---- modificador PCRE
--^ ^----
inicio fim
The letter i or any other after demilitarization is one of PCRE modifiers , i means that the expression will be parsed as case insensitive, ie it does not differentiate lowercase capitals that would be the equivalent of [a-zA-Z] .