Deletes spam comments, posts and local spam accounts. Place into Diasporas root, edit and run. Don't forget to set necessary environment variables.

diaspora_spam.rb

#!/usr/bin/env ruby

# List of spam accounts
spam_accounts = %w(spamacc@podA spamacc@podB spamacc@mypod)

# Delete comments even if spammer isn't a local user or spam isn't on a
# local users account.
# And delete posts of users in spam_accounts that aren't local.
always_delete = true

# Keep empty (%w() or []) to retract spam comments from remote accounts
# for all local users
retract_for = %w(userA userB)

###########################################################################

# Load diaspora environment
ENV['RAILS_ENV'] ||= "production"
require_relative 'config/environment'

local_spammers, remote_spammers = Person.where(diaspora_handle: spam_accounts).partition(&:local?)

# Retract all comments of local spammers and close their accounts
local_spammers.each do |spammer|
  Comment.where(author_id: spammer.id).each do |comment|
    spammer.owner.retract(comment)
   end
   spammer.owner.close_account!
end

# Retract all spam comments on posts of local users and delete the rest
Comment.where(author_id: remote_spammers.map(&:id)).each do |comment|
  post_author = comment.parent.author
  if post_author.local? && (retract_for.include?(post_author.owner.username) || retract_for.empty?)
    post_author.owner.retract(comment)
  elsif always_delete
    comment.destroy
  end
end

# Destroy posts of remote users if wanted
if always_delete
  Post.where(author_id: remote_spammers.map(&:id)).each(&:destroy)
end

The first step towards stopping my pod forever had to be disabling registrations. In the last few years I have got no observable help from anyone, this script is barely qualifying as useful and the spambots are pretty lively. There seem to be no admin-approval option, no antispam measures, hooks, whatever, and everything is slow as hell. Not providing real antispam support just doesn't cut it.

Nevertheless, here's my after-the-fact script, which calls this code above with the modification of

spam_accounts = ARGV[0]

#!/bin/bash
# dewankerer.sh by grin, 2020
# gplv3+ or cc-by-sa-4.0 

# database user, host, dbname
DBU="pora"
DBH="1.7.1.2"
DBDB="pora"

SQL_GET_SPAMMER="SELECT username, getting_started, language, email,
        sign_in_count, last_sign_in_at, last_sign_in_ip, last_seen
  FROM users
  WHERE last_sign_in_ip IN ('51.91.67.153','151.80.230.21','85.113.129.7','178.159.37.139')                                                                          
  ORDER BY username;"

# .pgpass  
psql -h $DBH -U $DBU $DBDB -c "${SQL_GET_SPAMMER}"

psql -h $DBH -U $DBU $DBDB -tA -c "${SQL_GET_SPAMMER}" | awk -F'|' '{ print $1} ' | \
        while read user; do
                echo ">>${user}>>"
                ./z_delete_user.rb "${user}@spora.grin.hu"
        done

or I often replace the SQL above with

SELECT username, getting_started, language, email, 
        sign_in_count, last_sign_in_at, last_sign_in_ip, last_seen
  FROM users
  WHERE sign_in_count=1 AND last_seen+'1 day'::INTERVAL < NOW()
  ORDER BY last_seen ;

to kill accounts older than a week and logged in only once.