mod reports: autoreport spam and autoban spammers.

* Automatically generate a mod report when a comment, forum post, or
  dmail is detected as spam.
* Automatically ban users that receive too many automatic spam reports
  within a short window of time.
* Automatically mark spam dmails as deleted.
* Change ban threshold from 10 spam reports in 24 hours to 10 reports in 1 hour.
* Change ban length from 3 days to forever.

app/logical/spam_detector.rb

@@ -4,6 +4,12 @@
 class SpamDetector
   include Rakismet::Model
 
+  # if a person receives more than 10 automatic spam reports within a 1 hour
+  # window, automatically ban them forever.
+  AUTOBAN_THRESHOLD = 10
+  AUTOBAN_WINDOW = 1.hours
+  AUTOBAN_DURATION = 999999
+
   attr_accessor :record, :user, :user_ip, :content, :comment_type
   rakismet_attrs author: proc { user.name },
                  author_email: proc { user.email },
@@ -24,6 +30,23 @@ class SpamDetector
     false
   end
 
+  def self.is_spammer?(user)
+    return false if user.is_gold?
+
+    automatic_reports = ModerationReport.where("created_at > ?", AUTOBAN_WINDOW.ago).where(creator: User.system)
+
+    dmail_reports = automatic_reports.where(model: Dmail.sent_by(user))
+    comment_reports = automatic_reports.where(model: user.comments)
+    forum_post_reports = automatic_reports.where(model: user.forum_posts)
+
+    report_count = dmail_reports.or(comment_reports).or(forum_post_reports).count
+    report_count >= AUTOBAN_THRESHOLD
+  end
+
+  def self.ban_spammer!(spammer)
+    spammer.bans.create!(banner: User.system, reason: "Spambot.", duration: AUTOBAN_DURATION)
+  end
+
   def initialize(record, user_ip: nil)
     case record
     when Dmail

app/models/comment.rb

@@ -2,13 +2,14 @@ class Comment < ApplicationRecord
   include Mentionable
 
   validate :validate_creator_is_not_limited, :on => :create
-  validate :validate_comment_is_not_spam, on: :create
   validates_presence_of :body, :message => "has no content"
   belongs_to :post
   belongs_to :creator, class_name: "User"
   belongs_to_updater
   has_many :moderation_reports, as: :model
   has_many :votes, :class_name => "CommentVote", :dependent => :destroy
+
+  before_create :autoreport_spam
   after_create :update_last_commented_at_on_create
   after_update(:if => ->(rec) {(!rec.is_deleted? || !rec.saved_change_to_is_deleted?) && CurrentUser.id != rec.creator_id}) do |rec|
     ModAction.log("comment ##{rec.id} updated by #{CurrentUser.name}", :comment_update)
@@ -97,8 +98,10 @@ class Comment < ApplicationRecord
     end
   end
 
-  def validate_comment_is_not_spam
-    errors[:base] << "Failed to create comment" if SpamDetector.new(self).spam?
+  def autoreport_spam
+    if SpamDetector.new(self).spam?
+      moderation_reports << ModerationReport.new(creator: User.system, reason: "Spam.")
+    end
   end
 
   def update_last_commented_at_on_create

app/models/dmail.rb

@@ -1,10 +1,6 @@
 require 'digest/sha1'
 
 class Dmail < ApplicationRecord
-  # if a person sends spam to more than 10 users within a 24 hour window, automatically ban them for 3 days.
-  AUTOBAN_THRESHOLD = 10
-  AUTOBAN_WINDOW = 24.hours
-  AUTOBAN_DURATION = 3
 
   validates_presence_of :title, :body, on: :create
   validate :validate_sender_is_not_banned, on: :create
@@ -12,8 +8,10 @@ class Dmail < ApplicationRecord
   belongs_to :owner, :class_name => "User"
   belongs_to :to, :class_name => "User"
   belongs_to :from, :class_name => "User"
+  has_many :moderation_reports, as: :model
 
   after_initialize :initialize_attributes, if: :new_record?
+  before_create :autoreport_spam
   after_save :update_unread_dmail_count
   after_commit :send_email, on: :create
 
@@ -27,29 +25,6 @@ class Dmail < ApplicationRecord
   scope :sent, -> { where("dmails.owner_id = dmails.from_id") }
   scope :received, -> { where("dmails.owner_id = dmails.to_id") }
 
-  concerning :SpamMethods do
-    class_methods do
-      def is_spammer?(user)
-        return false if user.is_gold?
-
-        spammed_users = sent_by(user).where(is_spam: true).where("created_at > ?", AUTOBAN_WINDOW.ago).distinct.count(:to_id)
-        spammed_users >= AUTOBAN_THRESHOLD
-      end
-
-      def ban_spammer(spammer)
-        spammer.bans.create! do |ban|
-          ban.banner = User.system
-          ban.reason = "Spambot."
-          ban.duration = AUTOBAN_DURATION
-        end
-      end
-    end
-
-    def spam?
-      SpamDetector.new(self).spam?
-    end
-  end
-
   module AddressMethods
     def to_name=(name)
       self.to = User.find_by_name(name)
@@ -72,7 +47,6 @@ class Dmail < ApplicationRecord
           # recipient's copy
           copy = Dmail.new(params)
           copy.owner_id = copy.to_id
-          copy.is_spam = copy.spam?
           copy.save unless copy.to_id == copy.from_id
 
           # sender's copy
@@ -80,8 +54,6 @@ class Dmail < ApplicationRecord
           copy.owner_id = copy.from_id
           copy.is_read = true
           copy.save
-
-          Dmail.ban_spammer(copy.from) if Dmail.is_spammer?(copy.from)
         end
 
         copy
@@ -200,6 +172,13 @@ class Dmail < ApplicationRecord
     owner == to
   end
 
+  def autoreport_spam
+    if is_recipient? && SpamDetector.new(self).spam?
+      self.is_deleted = true
+      moderation_reports << ModerationReport.new(creator: User.system, reason: "Spam.")
+    end
+  end
+
   def update_unread_dmail_count
     return unless saved_change_to_id? || saved_change_to_is_read? || saved_change_to_is_deleted?
 

app/models/forum_post.rb

@@ -14,12 +14,12 @@ class ForumPost < ApplicationRecord
 
   before_validation :initialize_is_deleted, :on => :create
   before_save :update_dtext_links, if: :dtext_links_changed?
+  before_create :autoreport_spam
   after_create :update_topic_updated_at_on_create
   after_update :update_topic_updated_at_on_update_for_original_posts
   after_destroy :update_topic_updated_at_on_destroy
   validates_presence_of :body
   validate :validate_topic_is_unlocked
-  validate :validate_post_is_not_spam, on: :create
   validate :topic_is_not_restricted, :on => :create
   before_destroy :validate_topic_is_unlocked
   after_save :delete_topic_if_original_post
@@ -108,8 +108,10 @@ class ForumPost < ApplicationRecord
     votes.where(creator_id: user.id, score: score).exists?
   end
 
-  def validate_post_is_not_spam
-    errors[:base] << "Failed to create forum post" if SpamDetector.new(self, user_ip: CurrentUser.ip_addr).spam?
+  def autoreport_spam
+    if SpamDetector.new(self, user_ip: CurrentUser.ip_addr).spam?
+      moderation_reports << ModerationReport.new(creator: User.system, reason: "Spam.")
+    end
   end
 
   def validate_topic_is_unlocked

app/models/moderation_report.rb

@@ -7,6 +7,7 @@ class ModerationReport < ApplicationRecord
   validates :creator, uniqueness: { scope: [:model_type, :model_id], message: "have already reported this message." }
 
   after_create :create_forum_post!
+  after_create :autoban_reported_user
 
   scope :user, -> { where(model_type: "User") }
   scope :dmail, -> { where(model_type: "Dmail") }
@@ -54,6 +55,23 @@ class ModerationReport < ApplicationRecord
     updater.update(forum_post_message)
   end
 
+  def autoban_reported_user
+    if SpamDetector.is_spammer?(reported_user)
+      SpamDetector.ban_spammer!(reported_user)
+    end
+  end
+
+  def reported_user
+    case model
+    when Comment, ForumPost
+      model.creator
+    when Dmail
+      model.from
+    else
+      raise NotImplementedError
+    end
+  end
+
   def self.visible(user = CurrentUser.user)
     user.is_moderator? ? all : none
   end