Added StatusSimilarityService to check against spamming same statuses over and over

• Added:
- StatusSimilarityService to check against spamming same statuses over and over
- StatusSimilarityService check to PostStatusService and EditStatusService

app/services/edit_status_service.rb

@@ -25,6 +25,7 @@ class EditStatusService < BaseService
 
  return idempotency_duplicate if idempotency_given? && idempotency_duplicate?
 
+ validate_similarity!
  validate_links!
  validate_media!
  preprocess_attributes!
@@ -92,6 +93,10 @@ class EditStatusService < BaseService
  raise GabSocial::ValidationError, I18n.t('media_attachments.validations.images_and_video') if @media.size > 1 && hasVideoOrGif
  end
 
+ def validate_similarity!
+ raise GabSocial::NotPermittedError if StatusSimilarityService.new.call?(@text, @account.id)
+ end
+
  def validate_links!
  raise GabSocial::LinkBlockedError if LinkBlock.block?(@text)
  end

app/services/post_status_service.rb

@@ -34,6 +34,7 @@ class PostStatusService < BaseService
 
  return idempotency_duplicate if idempotency_given? && idempotency_duplicate?
 
+ validate_similarity!
  validate_links!
  validate_media!
  validate_group!
@@ -159,6 +160,10 @@ class PostStatusService < BaseService
  raise GabSocial::ValidationError, I18n.t('media_attachments.validations.images_and_video') if @media.size > 1 && hasVideoOrGif
  end
 
+ def validate_similarity!
+ raise GabSocial::NotPermittedError if StatusSimilarityService.new.call?(@text, @account.id)
+ end
+
  def validate_links!
  raise GabSocial::NotPermittedError if LinkBlock.block?(@text)
  end

app/services/status_similarity_service.rb

+# frozen_string_literal: true
+
+require 'similar_text'
+
+class StatusSimilarityService < BaseService
+ def call?(status_text = "", account_id = nil)
+ @status_text = status_text
+ @account_id = account_id
+
+ # Not alike if no status_text or no account
+ # : todo : come up with solution for same image spamming
+ return false if @status_text.length == 0 || @account_id.nil?
+
+ alike?
+ end
+
+ private
+
+ def alike?
+ last_status_text = nil
+ key = "last_status_from_account:#{@account_id}"
+
+ Redis.current.with do |conn|
+ last_status_text = conn.get(key) || ""
+ conn.setex(key, 300, @status_text)
+ end
+
+ if last_status_text.nil? || last_status_text.empty? || last_status_text.length == 0
+ return false
+ end
+
+ likeness = last_status_text.similar(@status_text)
+
+ likeness > 85
+ end
+
+end

[Rubicon]

Rails provides a blank? method (and present?, which is just !blank?) on all classes. It’s got some specialized logic depending on the class of the receiver. For strings, it makes sure that it’s not empty (empty? is a C function that does length == 0), and also that it’s not whitespace only.

https://rubyapi.org/2.6/o/string#method-i-empty-3F

https://github.com/rails/rails/blob/main/activesupport/lib/active_support/core_ext/object/blank.rb

[Rubicon]

Should do similar with comments, but be sure to strip out tags before comparing similarity (but somehow not flag people saying “yes!” or other common legitimate relies). It seems like the bots actually use the UI, because they always include the correct tags in the beginning of their replies.