Citrix Systems Network Router 9.2 User Manual

You can extract text or a number and treat it like another type of data. For 
example, you can do the following:

•

Extract a string from an HTTP request body and treat it like an HTTP 
header. 

•

Extract a value from one type of request header and insert it in a response 
header of a different type.

After typecasting the data, you can apply any operation that is appropriate for the 
new data type. For example, if you typecast text to an HTTP header, you can 
apply any operation that is applicable to HTTP headers to the returned value.

http header.REGEX_

SELECT(regular expression)

Selects the text that matches the regular expression 
argument in any instance of the http header value. 
The header instances are matched from the last to 
the first.

The following example selects "NS-CACHE-9.0: 
90":

http.req.header("via").regex_

select(re!NS-CACHE-

\d\.\d:\s*\d{1,3}!)