When simple extraction of the cookie values or parameter values is not sufficient for configuration purposes, you can search the value for a sub-pattern that you define as a "regular expression" (or "regex").
This functionality is suitable for expert users.
- If you are new to software services, start with Software services for beginners before you come here.
- If you want to monitor a well-known software service, start with Autodiscovered Software Services to see if your work has already been done for you.
- If you find you still need to define your own software service, try to use the wizard or a template to walk you through the process. You can always use the manual screens to tweak a software service after you create it with the wizard. See Software Services for details.
The regular expressions used here conform to the Basic POSIX syntax. A full description of the syntax is widely available in numerous online and printed publications. The example below demonstrates a simple use of such a regular expression to extract a substring from a cookie value. For more information, see Regular expression fundamentals.
Regular expressions are symbolic patterns with which you can specify a range of text patterns. A single regular expression can match a wide range of very different text strings. For example, the expression “
. ” is a wildcard that matches any single character and the expression “
.* ” is a wildcard that matches any number of occurrences of any character (in effect, it matches anything).
Regular expressions can be used for finding particular text strings and then extracting certain parts of those text strings: the parts that match a sub-expression. The sub-expression is surrounded by parentheses
() . For example, the expression “
a(b.) ” finds all strings composed of three characters, of which the first one is “
a ”, the second one is “
b ”, and the third one is any character. It will then extract the second and third character. Note, however, that the match has to be based on the regular expression part outside the parentheses and the part inside the parentheses. In other words, the character “
a ” has to be found in the string, even though it is not extracted.
See Regular expression fundamentals for a list of common regular expression symbols and an example of how a regular expression is interpreted.