CODEWITHSUNDEEP
phpregex
user569322
user569322

Reputation:

PHP replace link in tags like [LINK]

In PHP, I want to make it so that if a user types:

[LINK] url [/LINK]

It will replace it with the anchor tag:

<a href=url>url</a>

How would I show this? I'm not sure how to translate this into regex...

I've tried the following:

[LINK][a-zA-Z0-9_-.]+[/LINK]

But obviously that isn't right :(

Upvotes: 0

Views: 462

Answers (2)

Lawrence Cherone
Lawrence Cherone

Reputation: 46660

Catch links but would always require leading http:// or https:// else the url would be example.com/google.com also you should use preg_replace_callback() as its possible to xss unsanitized input.

Here are some examples:

<?php
//The callback function to pass matches as to protect from xss.
function xss_protect($value){
    if(isset($value[2])){
        return '<a rel="nofollow" href="'.htmlentities($value[1]).'">'.htmlentities($value[2]).'</a>';
    }else{
        return '<a rel="nofollow" href="'.htmlentities($value[1]).'">'.htmlentities($value[1]).'</a>';
    }
}


$link ='[LINK]http://google.com[/LINK]';
$link = preg_replace_callback("/\[LINK\](.*)\[\/LINK\]/Usi", "xss_protect", $link);
echo $link;
?>
<a rel="nofollow" href="http://google.com">google.com</a>

Or Strip the http:// & https:// from the link then append it when outputting.

<?php
$link ='[LINK]google.com[/LINK]';
$link = preg_replace_callback("/\[LINK\](.*)\[\/LINK\]/Usi", "xss_protect", str_replace(array('http://','https://'),'',$link));
echo $link;
?>
<a rel="nofollow" href="http://google.com">google.com</a>

Or A different way to have BB code links, then you can specify Link name from link address, the call back function can be made to handle multiple types of outputs.

<?php
$link ='[LINK=google.com]Google[/LINK]';
$link = preg_replace("/\[LINK=(.*)\](.*)\[\/LINK\]/Usi", "xss_protect", str_replace(array('http://','https://'),'',$link));
echo $link;
?>
<a rel="nofollow" href="http://google.com">Google</a>

Upvotes: 0

flowfree
flowfree

Reputation: 16462

$str = '[LINK]http://google.com[/LINK]';
$str = preg_replace('/\[link\]([^\[\]]+)\[\/link\]/i', '<a href="$1">$1</a>', $str);

echo $str; // <a href="http://google.com">http://google.com</a>

Explanation:

\[link\]    Match "[LINK]"
([^\[\]]+)  Match any character except "[" and "]"
\[\/link\]  Match "[/LINK]"
i           Make it case-insensitive

Upvotes: 1

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