How to transform normal text into link

[robertboyle]

Hello,

I am wondering how we could transform a normal text into a link using PHP.

What I mean is:

- the user submits a form with the text http://www.yahoo.com in it,

- when he goes to see his submitted text, I want "http://www.yahoo.com" to be, in HTML, "<a href=http://www.yahoo.com>http://www.yahoo.com</a>", or, in other words, a link to Yahoo.com.

I have been trying for hours...

Any help is fully appreciated.

Thanks.

[grahame]

If his input is in a form element called "URL", then:

$sayvar = htmlspecialchars(stripslashes($_REQUEST[url]));
$result = "<a href=\""$sayvar\">$sayvar</a>";
print $result;

Note - it could be much shorter, but the code above deals with some security issues if you have malicious users.

[robertboyle]

Yes, I knew how to do that, it's easy... but if the submitted element contains other text than just the link, then what do I do?

Example: "Check out http://www.google.com to search the Internet."

How do I transform normal text "http://www.google.com" in a link?

Robert

[masonbarge]

What is the source of the text?

Check out stristr(). I think you can probably write this yourself. I'd do a little more but I don't know how to use a wildcard in stristr(). There might be a better function but that will get you pointed right.

[robertboyle]

Ok, so let me re-explain my problem:

Using a form, the user submits normal text to the server through a textarea. Ex: "I love http://www.google.com because it's simple."

If he submits a link, like in the example above, I want PHP to identify it and transform it into an actual link that the user can click when viewing his submitted text. I want PHP to scan the text, locate "http://" and transform it into "<a href=...>", and add an "</a>" at the end of the link.

Just like on this forum, when you submit a reply containing http://www.google.com, it actually transforms it into a true, clickable link that user can click on when displayed on the thread.

Any ideas?

Thanks.

[ukgeoff]

You are going to have to parse the text using regex to look for a sub-string that is a valid hyperlink.

Trouble is you could find a sub-string that is a valid hyperlink befor you have actually got to the end of the intended hyperlink.

E.g.
http://blah.org and http://blah.org.uk are both valid.

You could of course, having recognised valid start points for a hyperlink assume that it will end with the first space. Having retrieved that sub-string, you could then validate that as a hyperlink.

[masonbarge]

Bah. My feeble braincell just realized.

Code: Select all

$txt = $_POST ['name'];
$urls = explode(" ",$txt);
foreach ($urls as $value) {
$htp = substr($value, 0, 7);
    if ($htp == "http://")  {
                        $link = substr($value, 7);
                        echo ('<a href="' . $value . '">' . $link . '</a>');
    }
}

Piece of cake using explode(). There are some holes in it, but maybe some form validation would fill a few of them. Anything but a space before the citation will completely mess it up, so you might want to strip out some common formatting expressions like quotation marks, tabs. etc.

Also, it would go a long way if you simply tell them to make sure there is a single space before any url.

[robertboyle]

Hi masonbarge,

Indeed, that is a cool code, but it only returns the links, not the whole text in itself. How can I return the whole text (with the links inside)?

Also, can't we find such a code in open source forums like this one (or phpBB). I've been looking into their sources but have found nothing yet.

[masonbarge]

Code: Select all

$txt = $_POST ['name'];
$urls = explode(" ",$txt);
foreach ($urls as $value) {
$htp = substr($value, 0, 7);
    if ($htp == "http://")  {
                        $link = substr($value, 7);
                        echo ('<a href="' . $value . '"> ' . $link . '</a>');
    } else {
            echo " $value";
}

Notice the space in [["_$value" ]]and also [[$value . '">_' ]] .

[robertboyle]

OK, so now the whole text is returned with the link in it. Thanks a lot, MasonBarge! (you might wanna add a final } in the code to close the foreach).

Also, anyone that finds a more secure, more performant code, please post it.

Thanks

Robert