Citrix Systems Network Router 9.2 User Manual

http header.

INSTANCE(instance 

number)

An HTTP header can occur multiple times in a request 
or a response. This operation returns the header that 
occurs instance number of places before the final 
instance. For example, instance(0) selects the last 
instance of the current type, instance(1) selects the 
next-to-last instance, and so on. This prefix cannot be 
used in bidirectional policies.

The instance number argument cannot exceed 14. 
Following is an example of a request with two headers:

HTTP/1.1 200 OK\r\n

MyHeader: abc\r\n

Content-Length: 200\r\n

MyHeader: def\r\n

\r\n

The following returns a text object that refers to 
"MyHeader: abc\r\n":

http.res.header("MyHeader").instance(1) 

http header.

SUBSTR("string")

Extracts the text that matches the string argument. The 
headers are evaluated from the last instance to the first. 
Following is an example of a request with two headers 
that contain the string “111”:

HTTP/1.1 200 OK\r\n

MyHeader: abc111\r\n

Content-Length: 200\r\n

MyHeader: 111def\r\n

\r\n

The following returns "111" from the last instance of 
MyHeader. This is the header with the value "111def".

http.res.header("MyHeader").

substr("111")