Citrix Systems 9.2 manual Matching Text With a Pattern

164 Citrix NetScaler Policy Configuration and Reference Guide

show policy patset pattern_name

Where patternName is the name of a pattern that you want to view.

4.Configure the pattern set as part of an expression.

For example, you can configure it in a policy rule. For more information, see “Creating or Modifying an Advanced Policy,” on page 14. Following is an example that uses the pattern set myPatSet, and returns TRUE if the value of the HTTP header named myHeader contains any of the strings that you defined earlier in this procedure:

add cache policy testPatSet -rule http.req.header("myHeader").contains_index("myPatSet1") - action cache

Matching Text With a Pattern

In addition to matching text with a set of patterns, you can define an arbitrary pattern that uses wildcards. In most types of expressions, you should avoid using wildcards. For example, the following expression is legal but may have unexpected results:

http.req.url.path.contains("/*.jpeg")

Note that this expression would not, for example, match the following URL: http://10.102.58.201/icon.jpeg

Following is an example of a regular expression that matches a URL that contains the file name suffix, “.jpeg”:

http.req.url.regex_match(re/*.jpeg/)

In general, for simple pattern matching, it is preferable to use the CONTAINS or EQ operation to perform a partial string match. For example, the following expressions check the file name extension:

http.req.url.suffix.contains("jpeg")

http.req.url.suffix.eq("jpeg")

However, if you need to match more complex patterns in text, you can define a regular expression. For example, the following example selects "text" from "text/ plain":

http.res.header("content-type").before_regex(re#/#)

The NetScaler supports regular expression syntax as described on the following Web site:

http://www.pcre.org/pcre.txt

For an introduction to regular expressions, see the following URLs: