Specifying URL regular expressions (url_regex)
Entries of type url_regex within the configuration files use regular expressions to perform a match.
The following table offers examples to illustrate how to create a valid url_regex.
Value | Description |
---|---|
x | Matches the character x. |
. | Match any character. |
^ | Specifies beginning of line. |
$ | Specifies end of line. |
[xyz] | A character class. In this case, the pattern matches either x, y, or z. |
[abj-oZ] | A character class with a range. This pattern matches a, b, any letter from j through o, or Z. |
[^A-Z] | A negated character class. For example, this pattern matches any character except those in the class. |
r* | Zero or more r’s, where r is any regular expression. |
r+ | One or more r’s, where r is any regular expression. |
r? | Zero or one r, where r is any regular expression. |
r{2,5} | From two to five r’s, where r is any regular expression. |
r{2,} | Two or more r’s, where r is any regular expression. |
r{4} | Exactly 4 r’s, where r is any regular expression. |
"[xyz]\"images" | The literal string [xyz]"images" |
\X | If X is a, b, f, n, r, t, or v, then the ANSI-C interpretation of \x; Otherwise, a literal X. This is used to escape operators such as *. |
\0 | A NULL character. |
\123 | The character with octal value 123. |
\x2a | The character with hexadecimal value 2a. |
(r) | Matches an r; where r is any regular expression. You can use parentheses to override precedence. |
rs | The regular expression r, followed by the regular expression s. |
r|s | Either an r or an s. |
#<n># | Inserts an end node causing regular expression matching to stop when reached. The value n is returned. |