This improvement introduces a new URL filter plugin "urlfilter-fast" (naming debatable) which is in use at Common Crawl since 2013 to apply a long list of filters.
- an exact (suffix) match against the host name is done to retrieve host/domain-specific regex rules
- applies a regular expression against the path (and query) component of the URL
What makes it faster than urlfilter-regex for common cases:
- regexes are selected by host name or it's domain suffix, so there are usually fewer rules to be checked. That's similar to
NUTCH-1838but any domain suffix can be matched including subdomain.domain.com, com or . for global rules. The selection by host name suffix is considerably fast.
- regexes are applied only to the path component (optionally including the query) and not the entire URL.
Matching against a shorter string can make a huge difference for more complex regular expressions.
- the rule to deny everything from a host or domain gets special treatment to be fast
More details about the rule format are found in the plugin's README.