How to replace plain URLs with links?

Question

I am using the function below to match URLs inside a given text and replace them for HTML links. The regular expression is working great, but currently I am only replacing t

Answer 1

Keep it simple! Say what you cannot have, rather than what you can have :)

As mentioned above, URLs can be quite complex, especially after the '?', and not all of them start with a 'www.' e.g. maps.bing.com/something?key=!"£$%^*()&lat=65&lon&lon=20

So, rather than have a complex regex that wont meet all edge cases, and will be hard to maintain, how about this much simpler one, which works well for me in practise.

Match

http(s):// (anything but a space)+

www. (anything but a space)+

Where 'anything' is [^'"<>\s] ... basically a greedy match, carrying on to you meet a space, quote, angle bracket, or end of line

Also:

Remember to check that it is not already in URL format, e.g. the text contains href="..." or src="..."

Add ref=nofollow (if appropriate)

This solution isn't as "good" as the libraries mentioned above, but is much simpler, and works well in practise.

if html.match( /(href)|(src)/i )) {
    return html; // text already has a hyper link in it
    }

html = html.replace( 
            /\b(https?:\/\/[^\s\(\)\'\"\<\>]+)/ig, 
            "$1" 
            );

html = html.replace( 
            /\s(www\.[^\s\(\)\'\"\<\>]+)/ig, 
            "$1" 
            );

html = html.replace( 
             /^(www\.[^\s\(\)\'\"\<\>]+)/ig, 
            "$1" 
            );

return html;