Filtering sources

You can limit which items of sources will be stored in the database by specifying a filter expression in the “Filter” field of a source on the Settings page.

The filter expression can take one of the following forms:

1. An atomic filter: a Perl-compatible regular expression, as accepted by PHP, between forward slashes (/). For example, /reg(ular expression|ex)/ will keep only items whose title or content matches the regular expression between the slashes (i.e. contain the phrase “regular expression” or “regex”). Learn more about regular expressions on https://www.regular-expressions.info/.
2. A field-specific filter: an atomic filter preceded by one of the field names below and a colon:
   • title:/regex/ will keep only items whose title matches the regular expression between the slashes.
   • content:/regex/ will keep only items whose content matches the regular expression between the slashes.
   • url:/regex/ will keep only items whose URL matches the regular expression between the slashes. For example, url:/^https:\/\/www\.bbc\.co\.uk\/sport\// will match all articles in sport section of BBC news.
   • author:/regex/ will keep only items which have an author that matches the regular expression between the slashes.
   • category:/regex/ will keep only items which have a category that matches the regular expression between the slashes.
3. A negated filter is either an atomic filter or a field-specific filter preceded by an exclamation mark (!). It will only keep items would not be kept by the filter after the exclamation mark.