Citrix Systems 9.2 manual Matching Text With Strings in a Set

CHAPTER 9

Advanced Expressions: String Sets,

String Patterns, and Data Formats

You can configure an operation that matches text in a target against a set of strings (an array) or a single string within an array. You can also match a target against a pattern defined in a regular expression. You can use a regular expression to specify wildcard characters in a pattern, such as text, numbers, and spaces.

Finally, you can use typecasting to convert one type of data into another type. For example, you can extract a string from an HTTP request POST body and format it as an HTTP header for the purpose of inserting the header into an HTTP response.

In This Chapter

Matching Text With Strings in a Set

Matching Text With a Pattern

Transforming Text and Numbers into Different Data Types

Matching Text With Strings in a Set

A pattern set compares a target with multiple static strings. A pattern set can be efficient if an expression would otherwise have a large number of Boolean OR operations. A pattern set reduces the overhead that would be required to process the ORs.

For example, you can define a pattern set with the strings “host1” and “host2”, “host3” and compare the target against each string. You can also compare the target with just one particular string in the set. For example, you can define a pattern set with the strings “vserver1”, “vserver2”, vserver3” and compare the target against only the string “vserver1”. For this type of comparison, you specify a unique index that is assigned to each string in the pattern set.

You can use a pattern set in any expression that evaluates HTTP headers or text. For information about expression prefixes for HTTP headers, see “Expressions for HTTP Headers,” on page 115. For information about expression prefixes for text, see “Expression Prefixes for Text,” on page 67.