Regex to exclude a domain

Is it as simple as this?

(!(www\.foobar\.com))

I don't understand your example entirely, but I think you should be quoting the dot at least:

(?:(?!foobar)\.)*

Select allOpen in new window

Well, that foobar domain has different third level domains depending on what type of element we are using from it.

Basically I'm grouping the string in a passive group and using a negative lookahead to filter out foobar and everything that goes after it. That's why I have the dot there so I don't think I want to be escaping that.

--Jose

I have written many regex, but that approach sounds very complicated.

Please show us a few specific examples of strings you are trying to match (or not match) so we can understand why it is so difficult.  Also these examples will give us something to test against.

What about this:

(?<!foobar)\.com

Select allOpen in new window

Correction:

[^/]+?(?<!foobar)\.com

Select allOpen in new window

Kaufmed,

That example filters everything out, not just the foobar elements.

sjklein42,

Well, basically let's say there's 5 elements that make up my site coming from a few different urls.

For example:

http://www.myhomepage.com/home.css    -----  takes 2 seconds to load
http://static.foobar.com/picture.jpg   ------   takes 1 second to load
http://videos.foobar.com/video.flv   -----   takes 4 seconds to load
http://www.adserver.com/ads/for/you.jpg   -----   takes 3 seconds to load
http://www.foobar.com/whatever   -----   takes 3 seconds to load

Very simplified but that's the idea. So my page took 13 seconds to load. I want to filter out all foobar.com stuff.

I would be left with 2 urls for a load time of 5 seconds. That's what I want to do. You can ignore the load time stuff since it's not pertinent to the regex but that's the idea behind wanting to filter out the foobar stuff.

Like I said, depending on the type of element, the subdomain is different so I need the regex to account for that. That's why I grouped foobar. At least that was my thinking. But it's not foolproof and I don't know why.

Does this clarify my problem?

--Jose

Well if you're app is receiving the url including the protocol, then we'd have to modify the pattern a bit. This should handle either scenario, but you can remove the question mark and non-capturing group if you expect you will always receive "http://" to start a URL.

^(?:http://)?[^/]+?(?<!foobar)\.com

Select allOpen in new window

yes, the urls are always fqdn.

This pattern matches all the "foobar" lines but not the others.

(\/\/[^\/]*?\.foobar\.com\/)

Select allOpen in new window

It checks for "//" and then, before it sees the next /, it must see .foobar.com followed by the /.

This "matches" all the foobar lines.   Do you need the expression negated within the pattern itself or can you just use the "else" branch in your program where this is called?  [not seeing any greater context makes it a little hard to guess what you're doing - not even clear what language you're programming in).

This is a pre-built java-based app. I'm not changing its programming. I'm using an option for pattern matching that accepts regex. I don't know exactly which regex it accepts as I'm not familiar with the different types and their differences.

I want to simply negate the pattern match.

Btw, that last example didn't work. Nothing was matched.

Can you tell us whether or not your application is using find() vs. match()? That would make a difference on the pattern construction  : )

Also, pleas note that since you say this is java, you will have to double-up any backslashes which are to be interpreted as regex escapes and not java escapes.

E.g.

// Wrong
^(?:http://)?[^/]+?(?<!foobar)\.com

// Correct
^(?:http://)?[^/]+?(?<!foobar)\\.com

Select allOpen in new window

Here's an example I worked up in Netbeans showing execution of the aforementioned pattern. Note that if I changed

    m.find();

to

    m.match();

the pattern would fail since match() expects to match the entire string to the regex, whereas find() just tries to match it against some substring in the source data.

public static void main(String[] args) {
    String pattern = "^(?:http://)?[^/]+?(?<!foobar)\\.com";

    System.out.println(CheckUrl(pattern, "http://www.myhomepage.com/home.css"));
    System.out.println(CheckUrl(pattern, "http://static.foobar.com/picture.jpg"));
    System.out.println(CheckUrl(pattern, "http://videos.foobar.com/video.flv"));
    System.out.println(CheckUrl(pattern, "http://www.adserver.com/ads/for/you.jpg"));
    System.out.println(CheckUrl(pattern, "http://www.foobar.com/whatever"));
}

public static boolean CheckUrl(String regex, String url) {
    Pattern p = Pattern.compile(regex);  // Find capturing parens in regex
    Matcher m = p.matcher(url);

    return m.find();
}

Select allOpen in new window

untitled.PNG

Oh I see. I don't which one it is using, I don't have that kind of access to the app but given your explanation, I think it's match() because your regex is failing for me.

It didnt completely answer my question but I was able to use it as a base to answer my own question.