Instruction manual

Appendix A: Policy Expressions
NetScaler 9000 Series Installation and Configuration Guide - Volume 1 A-3
NSICG60_JAN05
z Operators: Operators identify the operation that an object performs on its
operands.
z Operand: Operands define the values of the corresponding qualifiers.
The components of an expression are illustrated as follows.
Figure A-27 Diagrammatic representation of an expression
Note: For unary operators like EXISTS, NOTEXISTS and CONTENTS, no
operand should be given.
The following sections cover these components in detail.
A.1.1.1 Understanding Qualifiers
As mentioned earlier, the qualifier represents the information within a request
that needs to be tested. Qualifiers are generally components of HTTP requests
and headers.
The generalized format for specifying the qualifiers in expressions is:
[<flow-type>.<protocol>.]qualifier
Where flow-type can be either REQUEST or RESPONSE and protocol can be
HTTP, TCP or IP.
The following examples illustrate this format.
Example
REQUEST.HTTP.URL
In this example, the qualifier tests the contents of a URL.
The commonly used qualifiers are:
z METHOD: This qualifier deals with the HTTP request method, in general
GET and POST, although all HTTP/1.1 standard headers are accepted for
expressions (but not extensions such as the WebDAV method
ìSEARCHî).