Regular-expression pattern element. Optional in
Regular-expression pattern string.
<expression> element can be empty or contain a simple search string or a regular-expression pattern. The pattern is applied to the entire request string.
A match always occurs when
<expression> is empty or not specified; this is equivalent to specifying
The implementation is based on the Java package java.util.regex, which provides a regular-expression syntax similar to Perl’s.
The expression string must not contain literal < and & characters. These reserved characters can be encoded with
<, respectively, or the entire string can be enclosed in an XML
All characters between the
</expression> tags are passed to the regular expression parser, including characters outside the optional
CDATA section. Care should be taken to avoid extra whitespace.