Development PHP : linkify user input

I would like to be able to create a link from user input.
The problem is the user input is a textarea and may not always contain a link.

Id like to be able to do this without haveing to have the user mark up their text.

I have the following

PHP:

$output = preg_replace("/(http:\/\/|(www\.))(([^\s<]{4,68})[^\s<]*)/", '<a href="http://$2$3" rel="nofollow">$2$4</a>', $input);

but it has some problems.
if the text to be made into a link is followed by a <br /> then everything after that until the end of the input string is converted into a link, not only that but the <br /> is part of the link text and thus automatically making it useless link.

regular expressions / preg_replace arent really my thing.

anyone care to help me out for a cookie?

 

I'm not great at regexes either, but I think if you change the [^\s<]* to [^\s\<]* it may work - I'm pretty sure the less than sign needs to be escaped. Alternately, you can try

PHP:

<?php
$text = ereg_replace("[[:alpha:]]+://[^<>[:space:]]+[[:alnum:]/]",
                     "<a href=\"\\0\">\\0</a>", $text);
?>

which is from the ereg_replace manual page.

You could just use str_replace to add in a space before <br /> tags before running the regex, too

 

I've fixed the regex.

PHP:

$input = "<span>test</span>www.test.com <br /><div id='test'><a href=\"http://www.test.net\">testing</a></div><br /> http://testing.org.uk ";

$output = preg_replace("/[\s|>]((http:\/\/|www\.)([a-z0-9\_\-]{4,64}([.][a-z]{2,4})+))[\s|\.|\,|\/|<]/i", "<a href=\"http://$1\" rel=\"nofollow\">$1</a>", $input);

echo $output;


[edit] The previous was broken for .co.uk names

 

ok well it works better but it still has issues if there is a line break after the text that is to be linkified.

id do an str_replace for <br /> but the raw newline is going into the DB '\n' so i tried a str_replace on that and it did no good

on data recall the returned data is run through nl2br()

should i linkify on insert or on recall? (that might be a stupid question)

 

You can't string replace a newline character (\n). You can however do it with a regular expression replace.

 

This works for me

PHP:

$input = "
<br />www.test1.com sub.domain.test2.name
<br />
<span>http://sub.domain.test3.org.uk</span><br />
    <div id=\"test\">
        <a href=\"http://www.test.net\">testing</a>
    </div>
<br />
www.test4.uk.net<br />";

$pattern = '{((http://)?([a-zA-Z0-9-.]+)(com|net|co.uk|uk.net|org.uk|name)(?!".*>))}';

$output = preg_replace($pattern, "<a href=\"$1\" rel=\"nofollow\">$1</a>", $input);

echo "<pre>";
echo htmlspecialchars($output);
echo "</pre>";

[edit] Final regex works perfectly

 

So here's what i have i know its messy but right now Im just trying to get ti to work then i will streamline it
But im still not having any luck with it. If the text is followed by a newline it breaks the linkify

PHP:

        $body = mysql_real_escape_string(strip_tags(stripslashes($_POST['post']), '<a></a><b></b><img>'));
        
        $body = preg_replace("/[\n]/",' \n',$body); // strips newline and adds a space buffered newline
        $body = preg_replace("/(http:\/\/|www\.)([a-z0-9\_\.\-]{4,64}[a-z]{2,6})([\s|\/|<])/i", '<a href="http://$2" rel="nofollow">$1$2</a>$3', $body);  // Linkify properly formatted text


should i just pass it through nl2br() then buffer the <br />'s with a space and then linkify it? for simplicity / "Just make it work" sake?

 

This should work correctly now.

PHP:

$input = "
www.test1.com sub.domain.test3.co.uk

www.testt.net blah blah

www.test4.co.uk
text";

$body = mysql_real_escape_string(strip_tags(stripslashes($input), '<a></a><b></b><img>'));

$output = preg_replace("/(http:\/\/|www\.)([a-z0-9\_\.\-]{4,64}[a-z]{2,6})(\\n)*/i", '<a href="http://$2" rel="nofollow">$1$2</a>', $body);

echo "<pre>";
echo htmlspecialchars($output);
echo "</pre>";