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Advanced Expressions: Parsing HTTP , TCP, and UDP Data
You can configure advanced expressions to parse the payload for HTTP requests
and responses, including headers and body content. For example, you can ensure
that an HTTP request or response contains a header of a particular type, or you
can extract a particular segment from a URL path. You can also configure
expressions to transform the URL encoding and apply HTML or XML “safe”
coding for subsequent evaluation.
Similarly, you can analyze the payload in a TCP or UDP packet using an
advanced expression. For example, you can extract the source or destination port
and evaluate DNS record types.
In This Chapter
About Evaluating HTTP and TCP Payload
Expressions for HTTP Headers
Expressions for Extracting Segments of URLs
Expressions for Numeric HTTP Payload Data Other Than Dates
Operations for HTTP, HTML, and XML Encoding and “Safe” Characters
Expressions for TCP, UDP, and VLAN Data
XPath and JSON Expressions
Note: You can also use text-based and numeric advanced expressions to
evaluate HTTP request and response data. For more information, see “Advanced
Expressions: Evaluating Text,” on page 63 and “Advanced Expressions: Working
with Dates, Times, and Numbers,” on page 95.