Here is a quick example of the use:

require_once 'php-spam-filter/spamfilter.php';
$text = "Do you want to purchase some [url=shadywebsite.ca]Canadian viagra[/url] from me?";

// Search in a specific blacklist (absolute paths can be used instead)
$filter = new SpamFilter(['blacklist-trading.txt']);
$result = $filter->check_text($text);
if ($result)
{
    echo "You like talking about economics and trading, right? Go away!";
}


// Search in all available blacklists
$filter = new SpamFilter();

$result = $filter->check_text($text);
if ($result)
{
    // Result contains the matched word (not the matched regular expression)
    // In our example, $result will contain the value "viagra".
    echo "There is a special place in hell reserved for people who talk about '$result' on my blog!";
}
else
{
	echo "Your comment is clean from all known spam!";
}

There is an additional function named spam_check_url(), but is currently just an alias for spam_check_text() until I have it wired up as I want it.

An example use of this library can be seen in IQAndreas/jekyll-static-comments.

The blacklists are stored as a submodule just to ease in updating the lists via automated scripts. For details on the formatting to use in the blacklists, see blacklists/README.md.

License

Pre-emptively released under GPLv3, but I may change this in the future to suit the needs of others.

I hate writing documentation.