How to strip out // comments but not http:// url in PHP

Question

I'm adding some minification to our cache.class.php and am running into an edge case that is causing me grief.

I want to remove all comments of the // variety, HOWEVER I don't want to remove URLs...

Given some example text here with carefully crafted cases:

// another comment here

function bookmarksite(title,url){
 if (window.sidebar) // firefox
 window.sidebar.addPanel(title, url, "");
 else if(window.opera &
 elem.setAttribute('href',url);
 elem.setAttribute('title',title);
 elem.setAttribute('rel','sidebar');
 elem.click();
 } 
 else if(document.all)// ie
 window.external.AddFavorite(url, title);
}

I've tried so many variations and hunted on StackOverflow, Google, etc. and what would seem like a task already solved, doesn't seem to be.

This is "close", but still matches //foo.com (omitting the : of course)

s*(?!:)//.*?$ (count it as '/m' multiline)

This ultimately ends up in a PHP line of code like so:

$sBlob = preg_replace("@s*//.*?$@m",'',$sBlob);

Here are some other links of stuff I've found and tried to experiment with varying degrees.

http://stackoverflow.com/questions/4568410/match-comments-with-regex-but-not-inside-a-quote
http://stackoverflow.com/questions/611883/regex-how-to-match-everything-except-a-particular-pattern
http://stackoverflow.com/questions/11863847/regex-to-match-urls-but-not-urls-in-hyperlinks
http://stackoverflow.com/questions/643113/regex-to-strip-comments-and-multi-line-comments-and-empty-lines

Answer 1

We have been using a native jsmin extension http://www.ypass.net/software/php_jsmin/ which does a lot more without any trouble for over two years now. It's much faster than the equivalent PHP solution and is probably tested by a lot more people than a home-grown version. You might want to check it out before going too far down this path.

Comments

I appreciate the pointer, but our files, like many people, is a mixture of
HTML, PHP and JS in one file. This jsmin appears to only work on .js files
right? Also, everything else works great in our minifing method, just this
edge case.

---

My bad. We moved all our JS and CSS to external files for this very reason and created a plugin to combine and minify everything needed by each page into a unique file. While it does cause some duplication across pages, it means that every page loads exactly one JS and CSS file each.

For your situation, I don't know a regular expression that will work in all cases.