Citrix Systems 9.2 Benutzerhandbuch

You can use parentheses to control the order of evaluation in a compound 
expression.

You configure compound expressions with the following operators:

•

&&. This operator is a logical AND. For the expression to evaluate to 
TRUE, all components that are joined by the And must evaluate to TRUE. 
Following is an example:

http.req.url.hostname.eq("myHost") && 

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

•

||. This operator is a logical OR. If any component of the expression that is 
joined by the OR evaluates to TRUE, the entire expression is TRUE.

•

!. Performs a logical NOT on the expression.

In some cases, the NetScaler configuration utility offers AND, NOT, and OR 
operators in the Add Expression dialog box. However, these are of limited use. 
Citrix recommends that you use the operators &&, ||, and ! to configure 
compound expressions that use Boolean logic.

You can use parentheses to control the order of evaluation of an expression. The 
following is an example:

http.req.url.contains("myCompany.com") || 

(http.req.url.hostname.eq("myHost") && 

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

The following is another example:

(http.req.header("Content-Type").exists && 

http.req.header("Content-Type").eq("text/html")) || 

(http.req.header("Transfer-Encoding").exists || 

http.req.header("Content-Length").exists)

The following table describes operators that you can use to configure compound 
operations on string data.
String-Based Operations for Compound Advanced Expressions

Operations that produce a string value