Citrix Systems 9.2 manual Transforming Text and Numbers into Different Data Types, First

Chapter 9 Advanced Expressions: String Sets, String Patterns, and Data Formats 169

Operations That Apply Regular Expressions to Text and HTTP Headers

Regular Expression Operation	Description
http header.REGEX_	Selects the text that matches the regular expression
SELECT(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}!)

Transforming Text and Numbers into Different Data Types

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.