Citrix Systems 9.2 manual STR string, Instance to the first, Following is an example of a request

124Citrix NetScaler Policy Configuration and Reference Guide

Operations That Evaluate HTTP Headers

HTTP Header Operation	Description
http header.AFTER_	Extracts the text that follows the first occurrence of the
STR("string")	string argument.The headers are evaluated from the last
	instance to the first.
	Following is an example of a request:
	HTTP/1.1 200 OK\r\n
	MyHeader: 111abc\r\n
	Content-Length: 200\r\n
	MyHeader: 111def\r\n
	\r\n
	The following extracts the string "def" from the last
	instance of MyHeader. This is value "111def".
	http.res.header("MyHeader").after_
	str("111")
	The following extracts the string "c" from the first
	instance of MyHeader. This is the value "abc111".
	http.res.header("MyHeader").after_
	str("1ab")
http header.BEFORE_	Extracts the text that appears prior to the first
STR("string")	occurrence of the input string argument.The headers are
	evaluated from the last instance to the first.
	Following is an example of a request that contains
	headers:
	HTTP/1.1 200 OK\r\n
	MyHeader: abc111\r\n
	Content-Length: 200\r\n
	MyHeader: def111\r\n
	\r\n
	The following extracts the string "def" from the last
	instance of MyHeader. This is the value "def111".
	http.res.header("MyHeader").before_
	str("111")
	The following extracts the string "a" from the first
	instance of MyHeader. This is the value "abc111".
	http.res.header("MyHeader").before_
	str("bc1")