Re: How to recognise url in a block of text

At 10/17/2006 12:39 AM, AYSERVE.NET wrote:

Please, I need help on how to to recognise url in a block of text being retrieved from a database and present it as a link within that text.

Here's an illustration of your problem: Input: Text text http://example.com/directory/filename.html#anchor text text http://www.example.com/filename.php?arg=val&arg=val text text. Output: Text text <a href="http://example.com/directory/filename.html#anchor">http://example.com/directory/filename.html#anchor</a> text text <a href="http://www.example.com/filename.php?arg=val&arg=val">http://www.example.com/filename.php?arg=val&arg=val</a> text text. Method: - find each URL within the text - replace each URL with an anchor tag that includes two copies of the URL, one in the href attribute and one enclosed in the tag. Technique: I'd use Regular Expressions for this:

        PHP - Regular Expression Functions (Perl-Compatible)
        http://php.net/pcre

To write your own regexp to identify URIs, you'll want to read the spec:

        RFC 1738 - Uniform Resource Locators (URL)
        http://www.faqs.org/rfcs/rfc1738.html

Specifically you'll need to know what characters can and cannot occur in an URL, and in what context, so that you can separate an URL from surrounding text and punctuation such as parentheses, periods, commas, etc. If you google "regular expression url" you'll find a lot of examples of regexp's that find URLs, including:

        Regex for URLs by Abigail
        http://foad.org/~abigail/Perl/url2.html

Have fun, Paul