Convert a string url to hyperlink

Question

Works for several links but if I put the same 2x link in the string does not work as do?

function MontarLink($texto)
{
       if (!is_string ($texto))
           return $texto;

    $er = "/(https:\/\/(www\.|.*?\/)?|http:\/\/(www\.|.*?\/)?|www\.)([a-zA-Z0-9]+|_|-)+(\.(([0-9a-zA-Z]|-|_|\/|\?|=|&)+))+/i";

    preg_match_all ($er, $texto, $match);

    foreach ($match[0] as $link)
    {

        //coloca o 'http://' caso o link não o possua
        $link_completo = (stristr($link, "http") === false) ? "http://" . $link : $link;

        $link_len = strlen ($link);

        //troca "&" por "&", tornando o link válido pela W3C
       $web_link = str_replace ("&", "&", $link_completo);
       $texto = str_ireplace ($link, "<a href=\"" . strtolower($web_link) . "\" target=\"_blank\">". (($link_len > 60) ? substr ($web_link, 0, 25). "...". substr ($web_link, -15) : $web_link) ."</a>", $texto);

    }

    return $texto;

}

echo MontarLink("ola mundo www.cade.com.br"); // ESSE FUNCIONA!!!
echo "<br><br>";
echo MontarLink("ola mundo www.cade.com.br outro site www.terra.com.br "); // ESSE FUNCIONA!!!
echo "<br><br>";
echo MontarLink("ola mundo www.cade.com.br mesmo site www.cade.com.br"); // NÃO FUNCIONA!!!

Answer 1

The problem is that when you find the first occurrence, you’re replacing them all, then you get the second repeated occurrence and you have them replaced again, and you go into a chain reaction, messing everything up...

Use the function preg_replace_callback:

function MontarLink($texto)
{
       if (!is_string ($texto))
           return $texto;

    $er = "/(https:\/\/(www\.|.*?\/)?|http:\/\/(www\.|.*?\/)?|www\.)([a-zA-Z0-9]+|_|-)+(\.(([0-9a-zA-Z]|-|_|\/|\?|=|&)+))+/i";

    $texto = preg_replace_callback($er, function($match){
        $link = $match[0];

        //coloca o 'http://' caso o link não o possua
        $link = (stristr($link, "http") === false) ? "http://" . $link : $link;

        //troca "&" por "&", tornando o link válido pela W3C
        $link = str_replace ("&", "&", $link);

        return "<a href=\"" . strtolower($link) . "\" target=\"_blank\">". ((strlen($link) > 60) ? substr ($link, 0, 25). "...". substr ($link, -15) : $link) ."</a>";
    },$texto); 

    return $texto;

}

echo MontarLink("ola mundo www.cade.com.br"); // ESSE FUNCIONA!!!
echo "<br><br>";
echo MontarLink("ola mundo www.cade.com.br outro site www.terra.com.br "); // ESSE FUNCIONA!!!
echo "<br><br>";
echo MontarLink("ola mundo www.cade.com.br mesmo site www.cade.com.br"); // ESSE FUNCIONA!!!

Answer 2

I did some digging and found that answer in Stack Overflow which in addition to solving your text-to-link problem still takes into account various particularities of a URL and even covers links of the type mailto, if anyone still uses them.

The original answer had some silly misconceptions which I fixed and will be making available here:

function makeClickableLinks( $text ) {

    $text = ' ' . html_entity_decode( $text );

    // Full-formed links

    $text = preg_replace(

        '#(((f|ht){1}tps?://)[-a-zA-Z0-9@:%_\+.~\#?&//=]+)#i',

        '<a href="\\1" target=_blank>\\1</a>',

        $text
    );

    // Links without scheme prefix (i.e. http://)

    $text = preg_replace(

        '#([[:space:]()[{}])(www.[-a-zA-Z0-9@:%_\+.~\#?&//=]+)#i',

        '\\1<a href="http://\\2" target=_blank>\\2</a>',

        $text
    );

    // E-mail links (mailto)

    $text = preg_replace(

        '#([_\.0-9a-z-]+@([0-9a-z][0-9a-z-]+\.)+[a-z]{2,3})#i',

        '<a href="mailto:\\1" target=_blank>\\1</a>',

        $text
    );

    return $text;
}

You can use it the same way you’ve been using it:

// Link com prefixo http:// e um mailto:

echo makeClickableLinks('

    This is a test clickable link: http://www.websewak.com  You can also try using an email address like [email protected]'
), '<br />';

// Links sem o prefixo http://

echo makeClickableLinks( 'www.cade.com.br' ), '<br />';

// Mais de um link no mesmo texto

echo makeClickableLinks(

    'ola mundo www.cade.com.br outro site www.terra.com.br'
), '<br />';

// Dois links iguais

echo makeClickableLinks(

    'ola mundo http://www.cade.com.br mesmo site http://www.cade.com.br'
), '<br />';