Match and replace with the captured/matched characters

Question

I currently have a code that finds and replaces urls into complete html links. It works fine but now i need to update it so that if there is image url then it should convert it into a html img tag and display it. Function im using now is...

function auto_link_text($text) {

   $pattern  = '#\b(([\w-]+://?|www[.])[^\s()<>]+(?:\([\w\d]+\)|([^[:punct:]\s]|/)))#';
   $callback = create_function('$matches', '
       $url       = array_shift($matches);
       $url_parts = parse_url($url);



       return sprintf(\'<a rel="nowfollow" target="_blank" href="%s">%s</a>\', $url, $url);
   ');

   return preg_replace_callback($pattern, $callback, $text);
}

Got it from... How to add anchor tag to a URL from text input

Here is an example of the text i would to it to go through...

asdf
http://google.com/
asfd
http://yahoo.com/logo.jpg
http://www.apple.com/sdfsd.php?page_id=13&id=18210&status=active#1
http://youtube.com/logo.png

like it updated function to output...

asdf
<a rel="nowfollow" target="_blank" href="http://google.com/">http://google.com/</a>
asfd
<img src="http://yahoo.com/logo.jpg" class="example">
<a rel="nowfollow" target="_blank" href="http://www.apple.com/sdfsd.php?page_id=13&id=18210&status=active#1">http://www.apple.com/sdfsd.php?page_id=13&id=18210&status=active#1</a>
<img src="http://youtube.com/logo.png" class="example">

Big thanks in advance!

I think it is better to make a new function for the image tag. Putting this much operation into one single function would make it messy. You can even make an object and then make two separate methods for simple-url-parsing and image-to-tag-conversion — Mostafa Talebi, Jul 12 '14 at 12:35

score 0 · Answer 1 · edited May 23 '17 at 10:32

Here is the nice post about the best suitable regex pattern for valid URL. I picked one from there to group all the URLs.

Online demo

Steps to follow:

simply extract the url.
put a check on the url and based on your own logic substitute the tag as shown in demo.

sample code: (get all the valid urls in groups. get it from index 1)

$re = "/(([A-Za-z]{3,9}:(?:\\/\\/)?(?:[-;:&=\\+\\$,\\w]+@)?[A-Za-z0-9.-]+|(?:www.|[-;:&=\\+\\$,\\w]+@)[A-Za-z0-9.-]+)((?:\\/[\\+~%\\/.\\w-_]*)?\\??(?:[-\\+=&;%@.\\w_]*)#?(?:[\\w]*))?)/";
$str = "...";

preg_match_all($re, $str, $matches);

sample code: (substitute anchor tag (or what ever you want to add))

$re = "/(([A-Za-z]{3,9}:(?:\\/\\/)?(?:[-;:&=\\+\\$,\\w]+@)?[A-Za-z0-9.-]+|(?:www.|[-;:&=\\+\\$,\\w]+@)[A-Za-z0-9.-]+)((?:\\/[\\+~%\\/.\\w-_]*)?\\??(?:[-\\+=&;%@.\\w_]*)#?(?:[\\w]*))?)/";
$str = "...";
$subst = '<a href="$1">$1</a>';

$result = preg_replace($re, $subst, $str);

Thanks but its mostly Greek to me. I could not get it to meet my requirements. Off topic but what is a good source to learn regex? — najamd, Jul 14 '14 at 10:28

Casimir et Hippolyte · Accepted Answer · 2014-07-12T14:00:51.490

You can use this for example:

function create_anchor_tag($url, $text = false) {
    if ($text===false) $text = $url;
    return '<a rel="no-follow" target="_blank" href="' . $url . '">'
         . $text . '</a>'; 
}

function create_image_tag($url) {
    return '<img src="' . $url . '"/>';
}

function auto_link_text($text) {
    $pattern = '~\b(?:(?:ht|f)tps?://|www\.)\S+(?<=[\PP?])~i';

    $callback = function ($m) {
        $img_ext = array('jpg', 'jpeg', 'gif', 'png');
        $path = parse_url($m[0], PHP_URL_PATH);
        $ext = substr(strrchr($path, '.'), 1);

        if (in_array(strtolower($ext), $img_ext))
            return create_image_tag($m[0]);
        return create_anchor_tag($m[0]); 
    };

    return preg_replace_callback($pattern, $callback, $text);
}

I used several functions to make it more clea[rn], but you can easily adapt it as you like.

Worked perfectly and easy to work with for my skill level. :) Thanks allot! — najamd, Jul 14 '14 at 10:26

Match and replace with the captured/matched characters

2 Answers2