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Advanced Expressions: Evaluating Text
You can configure an advanced expression to examine text in a request or a
response. For example, a expression can perform string matching on the
following types of data:
• An HTTP header type
• An HTTP header value
• A user or group name in an HTTP request
• A file type in a URL
• A string in an HTTP POST body
You can configure text expressions to be case sensitive or case insensitive and to
use or ignore spaces.You can also configure complex expressions for text, for
example, by skipping x number of bytes before starting a search of a POST body
or by finding a string that occurs after the end of another string.
The rest of this chapter discusses the expression prefixes that extract text and the
operations that you can perform on the extracted text.
In This Chapter
About Text Expressions
Expression Prefixes for Text
Operations on Text
Complex Operations on Text
Note: You can apply complex functions to text expressions. For example, you
can transform a text string to a name-value list. Or, you can perform a match
against a pattern or set of patterns. For information on these advanced text
expressions, see “Advanced Expressions: String Sets, String Patterns, and Data
Formats,” on page 157.