«No-links please!» Anti-spam WordPress plugin

This astonishing-simple and really-effective anti-SPAM system just works. It definitively protects your WordPress site from SPAM without imposing annoying CAPTCHAs, configurations, third-party services, blockchains, artificial intelligence or unicorns. Oh, just avoid URLs in comments when not logged-in :^)

If your SPAM always contains links this could be your definitive solution.

Why it works

You can't really stop SPAM-bots. Bots try to submit tons of links into your comments in the hope that search engines will index them. Fortunately WordPress already de-index them since years as default but unfortunately bots do their job anyway, shooting in the mass and hoping to find a way to spread their spam via web.

Here is the idea: applying a small "no links please!" netiquette you can pratically kill every SPAM-bot of this kind at their deep intentions, before even reaching your database.

Tl;dr If you do not write links you are a good human.

Features

• The SPAM is just dropped before reaching your database
• It does not annoy the average user (have you said CAPTCHA?)
• It does not need maintainment (have you said public blacklist?)
• It counts how much spam the system has blocked (for your personal satisfaction)
• You can display this counter from your Dashboard or from the [no_links_please_anti_spam_counter] shortcode
• Very lightweight and KISS design (keep it simple and stupid)
• It has not crapware

Known bugs

• None! Only features. asd

Installation

As every WordPress plugin:

1. Download this repository as .zip file (master.zip)
2. Activate the plugin

Customization

To customize the error message put this somewhere in the functions.php of your WordPress theme:

add_filter( 'no_links_please_anti_spam_error', function () {
	return "<b>Error</b>: Sir, please try again removing all the links from your comment. Yes, your comment was just dropped. Apologies, but SPAM is a bad beast.";
} );

To customize the netiquette message put this instead:

add_filter( 'no_links_please_anti_spam_netiquette', function () {
	return "Sir, before submitting just remember to avoid links. Cheers!";
} );

Credits

I would like to thank the veteran unix sysadmin Massimo Nuvoli as my spiritual reference in mastering about Italian profanities, and for his talk about SPAM fighting at Linux Day Torino 2018 as well.