Citrix Systems Network Router 9.2 User Manual

Following is an example that evaluates to TRUE if a response body of 1024 bytes 
contains the string “https”, and this string occurs after the string “start string” and 
before the string “end string”:

http.res.body(1024).after_str("start_string").before_str("end_

string").contains("https")

You can apply any text operation to the payload body. For information on 

operations that you can apply to text, see 

One common method of evaluating HTTP traffic is to examine the headers in a 
request or a response. A header can perform a number of functions, including the 
following:

•

Provide cookies that contain data about the sender.

•

Identify the type of data that is being transmitted.

•

Identify the route that the data has traveled (the Via header). 

As noted in the section 

, the EXISTS operation identifies if a request or a response contains a 

particular object. Following is a request-time example that determines if a 
particular header type exists:

http.req.header("myHeader").exists

You can configure expressions to identify almost any data in a header, including 
header types and values, and almost any type of information in a Cookie header.

Note that if the same operation is used to evaluate header and text data, 

the header-based operation always overrides any text-based operation.