findclass function doesnt work

Here are the docs for those methods:

domain() - Parses and returns up to the specified number of trailing parts of a domain name from the specified expression.

findclass() - The findclass() function finds the member of a class that starts with or matches the beginning of that class member. This function returns the value of that class member. This is similar to the one of class identifier, except that the member is not required to be equal; instead, the member is only required to start with the string and returns the entire member value.

getfield() - The getfield() function splits a string on a character, and returns the string corresponding to the specific field. The function returns an empty string if the value of does not evaluate into a string, or if the specified value is greater than the number of fields the evaluated was split into. If the specified character or string is not found in the evaluated , then it is treated as one field.

Let's break this down

x = domain(http_host,1)
y = findclass(x, myclass)
z = getfield(y, ',', 2)

So, let's say you are passing in the following uri: http://www.test1.com.

x = domain("www.test1.com", 1)
// x will now contain "com" since you specified 
// to return up to 1 trailing part of the domain name.

I don't think this is what you were going for. I believe that since you have the full domain name in the class, you don't need to be extracting the domain from the full host value.

I would try the following:

class myclass {
  www.test1.com,www.yahoo.com
  www.test2.com,www.msn.com
}
redirect to getfield(findclass(http_host, myclass), ',', 2)

Or, you if you want to redirect all domain level requests, you could do the following:

class myclass {
  test1.com,www.yahoo.com
  test2.com,www.msn.com
}
redirect to getfield(findclass(domain(http_host, 2), myclass), ',', 2)

Also, you might want to append the http_uri to the request if you want the uri portion of the redirect to match, otherwise the uri on the original request will be ignored.

-Joe

I tried

 

redirect to getfield(findclass(http_host, myclass), ',', 2)

 

but it didnt work. It doesnt get redirected for some reason.

 

Yeah ... I see the problem. There appears to be a bug in the rule evaluator. The findclass function actually matches a class member if it is a substring of the string to match. An example:

class animals {
    "bee"
    "beaver"
}
findclass("beer", animals) returns "bee"
findclass("be", animals) returns empty string
findclass("bumblebee", animals) returns "bee"
findclass("beaverbee", animals) returns "bee"

This bug prevents your solution from working.

I'm not sure that's the problem here since that would actually result in a redirect to the wrong place, not the lack of a redirect at all...

Correct, and it actually works that way in my tests. I'm using following config:

class hostmap {
    "test1.mm.lab,fernet.mm.lab"
    "test2.mm.lab,gin.mm.lab"
    "test3.mm.lab,rum.mm.lab"
}
rule mapper {
   redirect to "http://" + getfield(findclass(http_host, hostmap), ',', 2) +  http_uri
}
virtual 10.66.66.162:80 unit 1 {
    use rule mapper
}

Sending following request to the VIP:

GET /host.html HTTP/1.1
Host: test1.mm.lab

yields following response:

HTTP/1.0 302 Found
Location: http:///host.html
Connection: close

If I access the VIP with Firefox I get an Alert saying "www.host.html cannot be found, please check the URL and try again" and a blank window. This is what I expect because the URL in the Location header is really invalid.

What is "hotmap"?

 

Something specific to 9.x branch?

Sorry. Got it !

 

How come it is working for you? Can you do me a favor and do exactly what I am doing as mentioned in my original thread on this problem, and see if it works for you pl?

I've already tested configuration almost identical to the one you've posted in the first message in this thread. Results were similar. The only difference was the Location header in the 302 response looked like this:

 

 

Location: http://

 

 

and Firefox did not display the alert, just a blank page.

Sorry, but honestly I am confused now.

 

So do you mean it works for you in IE and not in Firefox? OR it works on both? Or it fails?

I've not tested with IE. As a matter of fact, the browser is irrelevant. All that matters is that BIG-IP actually generates a response. The response is useless because of invalid Location, which is caused by findclass working slightly differently than as documented. So, with "work" I mean that BIG-IP generates the redirect response. I've assumed that your problem was that the redirect (302) response has not been generated at all.

The solution (i.e., redirect based on matching a class member and parsing out the redirect target) cannot work because findclass will never match a class member that is longer than the string to match (as I've explained and demonstrated earlier).

The only way how to achieve what you want (if I understand your goal correctly) is to use a chain of if-else statements like this:

rule redir-map {
   if(http_host == "www.test1.com") {
       redirect to "http://www.yahoo.com"
   } 
   else if(http_host == "www.test2.com") {
       redirect to "http://www.msn.com"
   }

The smart solution using findclass is unfortunately not going to work.