discourse/app/models/topic.rb

893 lines
29 KiB
Ruby

require_dependency 'slug'
require_dependency 'avatar_lookup'
require_dependency 'topic_view'
require_dependency 'rate_limiter'
require_dependency 'text_sentinel'
require_dependency 'text_cleaner'
require_dependency 'archetype'
class Topic < ActiveRecord::Base
include ActionView::Helpers::SanitizeHelper
include RateLimiter::OnCreateRecord
include HasCustomFields
include Trashable
extend Forwardable
def_delegator :featured_users, :user_ids, :featured_user_ids
def_delegator :featured_users, :choose, :feature_topic_users
def_delegator :notifier, :watch!, :notify_watch!
def_delegator :notifier, :tracking!, :notify_tracking!
def_delegator :notifier, :regular!, :notify_regular!
def_delegator :notifier, :muted!, :notify_muted!
def_delegator :notifier, :toggle_mute, :toggle_mute
attr_accessor :allowed_user_ids
def self.max_sort_order
2**31 - 1
end
def featured_users
@featured_users ||= TopicFeaturedUsers.new(self)
end
def trash!(trashed_by=nil)
update_category_topic_count_by(-1) if deleted_at.nil?
super(trashed_by)
update_flagged_posts_count
end
def recover!
update_category_topic_count_by(1) unless deleted_at.nil?
super
update_flagged_posts_count
end
rate_limit :default_rate_limiter
rate_limit :limit_topics_per_day
rate_limit :limit_private_messages_per_day
validates :title, :presence => true,
:topic_title_length => true,
:quality_title => { :unless => :private_message? },
:unique_among => { :unless => Proc.new { |t| (SiteSetting.allow_duplicate_topic_titles? || t.private_message?) },
:message => :has_already_been_used,
:allow_blank => true,
:case_sensitive => false,
:collection => Proc.new{ Topic.listable_topics } }
validates :category_id,
:presence => true,
:exclusion => {
:in => Proc.new{[SiteSetting.uncategorized_category_id]}
},
:if => Proc.new { |t|
(t.new_record? || t.category_id_changed?) &&
!SiteSetting.allow_uncategorized_topics &&
(t.archetype.nil? || t.archetype == Archetype.default) &&
(!t.user_id || !t.user.staff?)
}
before_validation do
if SiteSetting.title_sanitize
self.title = sanitize(title.to_s, tags: [], attributes: []).strip.presence
end
self.title = TextCleaner.clean_title(TextSentinel.title_sentinel(title).text) if errors[:title].empty?
end
belongs_to :category
has_many :posts
has_many :topic_allowed_users
has_many :topic_allowed_groups
has_many :allowed_group_users, through: :allowed_groups, source: :users
has_many :allowed_groups, through: :topic_allowed_groups, source: :group
has_many :allowed_users, through: :topic_allowed_users, source: :user
has_one :top_topic
belongs_to :user
belongs_to :last_poster, class_name: 'User', foreign_key: :last_post_user_id
belongs_to :featured_user1, class_name: 'User', foreign_key: :featured_user1_id
belongs_to :featured_user2, class_name: 'User', foreign_key: :featured_user2_id
belongs_to :featured_user3, class_name: 'User', foreign_key: :featured_user3_id
belongs_to :featured_user4, class_name: 'User', foreign_key: :featured_user4_id
belongs_to :auto_close_user, class_name: 'User', foreign_key: :auto_close_user_id
has_many :topic_users
has_many :topic_links
has_many :topic_invites
has_many :invites, through: :topic_invites, source: :invite
has_many :revisions, foreign_key: :topic_id, class_name: 'TopicRevision'
# When we want to temporarily attach some data to a forum topic (usually before serialization)
attr_accessor :user_data
attr_accessor :posters # TODO: can replace with posters_summary once we remove old list code
attr_accessor :participants
attr_accessor :topic_list
attr_accessor :meta_data
attr_accessor :include_last_poster
# The regular order
scope :topic_list_order, -> { order('topics.bumped_at desc') }
# Return private message topics
scope :private_messages, -> { where(archetype: Archetype.private_message) }
scope :listable_topics, -> { where('topics.archetype <> ?', [Archetype.private_message]) }
scope :by_newest, -> { order('topics.created_at desc, topics.id desc') }
scope :visible, -> { where(visible: true) }
scope :created_since, lambda { |time_ago| where('created_at > ?', time_ago) }
scope :secured, lambda { |guardian=nil|
ids = guardian.secure_category_ids if guardian
# Query conditions
condition = if ids.present?
["NOT c.read_restricted or c.id in (:cats)", cats: ids]
else
["NOT c.read_restricted"]
end
where("category_id IS NULL OR category_id IN (
SELECT c.id FROM categories c
WHERE #{condition[0]})", condition[1])
}
# Helps us limit how many topics can be starred in a day
class StarLimiter < RateLimiter
def initialize(user)
super(user, "starred:#{Date.today.to_s}", SiteSetting.max_stars_per_day, 1.day.to_i)
end
end
before_create do
self.bumped_at ||= Time.now
self.last_post_user_id ||= user_id
if !@ignore_category_auto_close and self.category and self.category.auto_close_hours and self.auto_close_at.nil?
set_auto_close(self.category.auto_close_hours)
end
end
attr_accessor :skip_callbacks
after_create do
unless skip_callbacks
changed_to_category(category)
if archetype == Archetype.private_message
DraftSequence.next!(user, Draft::NEW_PRIVATE_MESSAGE)
else
DraftSequence.next!(user, Draft::NEW_TOPIC)
end
end
end
before_save do
unless skip_callbacks
if (auto_close_at_changed? and !auto_close_at_was.nil?) or (auto_close_user_id_changed? and auto_close_at)
self.auto_close_started_at ||= Time.zone.now if auto_close_at
Jobs.cancel_scheduled_job(:close_topic, {topic_id: id})
true
end
if category_id.nil? && (archetype.nil? || archetype == Archetype.default)
self.category_id = SiteSetting.uncategorized_category_id
end
end
end
after_save do
save_revision if should_create_new_version?
unless skip_callbacks
if auto_close_at and (auto_close_at_changed? or auto_close_user_id_changed?)
Jobs.enqueue_at(auto_close_at, :close_topic, {topic_id: id, user_id: auto_close_user_id || user_id})
end
end
end
# TODO move into PostRevisor or TopicRevisor
def save_revision
if first_post_id = posts.where(post_number: 1).pluck(:id).first
number = PostRevision.where(post_id: first_post_id).count + 2
PostRevision.create!(
user_id: acting_user.id,
post_id: first_post_id,
number: number,
modifications: changes.extract!(:category_id, :title)
)
Post.where(id: first_post_id).update_all(version: number)
end
end
def should_create_new_version?
!new_record? && (category_id_changed? || title_changed?)
end
def self.top_viewed(max = 10)
Topic.listable_topics.visible.secured.order('views desc').limit(max)
end
def self.recent(max = 10)
Topic.listable_topics.visible.secured.order('created_at desc').limit(max)
end
def self.count_exceeds_minimum?
count > SiteSetting.minimum_topics_similar
end
def best_post
posts.order('score desc').limit(1).first
end
# all users (in groups or directly targetted) that are going to get the pm
def all_allowed_users
# TODO we should probably change this from 3 queries to 1
User.where('id in (?)', allowed_users.select('users.id').to_a + allowed_group_users.select('users.id').to_a)
end
# Additional rate limits on topics: per day and private messages per day
def limit_topics_per_day
apply_per_day_rate_limit_for("topics", :max_topics_per_day)
limit_first_day_topics_per_day if user.added_a_day_ago?
end
def limit_private_messages_per_day
return unless private_message?
apply_per_day_rate_limit_for("pms", :max_private_messages_per_day)
end
def fancy_title
sanitized_title = if SiteSetting.title_sanitize
sanitize(title.to_s, tags: [], attributes: []).strip.presence
else
title.gsub(/['&\"<>]/, {
"'" => '&#39;',
'&' => '&amp;',
'"' => '&quot;',
'<' => '&lt;',
'>' => '&gt;',
})
end
return unless sanitized_title
return sanitized_title unless SiteSetting.title_fancy_entities?
# We don't always have to require this, if fancy is disabled
# see: http://meta.discourse.org/t/pattern-for-defer-loading-gems-and-profiling-with-perftools-rb/4629
require 'redcarpet' unless defined? Redcarpet
Redcarpet::Render::SmartyPants.render(sanitized_title)
end
def new_version_required?
title_changed? || category_id_changed?
end
# Returns hot topics since a date for display in email digest.
def self.for_digest(user, since, opts=nil)
opts = opts || {}
score = "#{ListController.best_period_for(since)}_score"
topics = Topic
.visible
.secured(Guardian.new(user))
.joins("LEFT OUTER JOIN topic_users ON topic_users.topic_id = topics.id AND topic_users.user_id = #{user.id.to_i}")
.where(closed: false, archived: false)
.where("COALESCE(topic_users.notification_level, 1) <> ?", TopicUser.notification_levels[:muted])
.created_since(since)
.listable_topics
.includes(:category)
if !!opts[:top_order]
topics = topics.joins("LEFT OUTER JOIN top_topics ON top_topics.topic_id = topics.id")
.order(TopicQuerySQL.order_top_for(score))
end
if opts[:limit]
topics = topics.limit(opts[:limit])
end
# Remove category topics
category_topic_ids = Category.pluck(:topic_id).compact!
if category_topic_ids.present?
topics = topics.where("topics.id NOT IN (?)", category_topic_ids)
end
# Remove muted categories
muted_category_ids = CategoryUser.where(user_id: user.id, notification_level: CategoryUser.notification_levels[:muted]).pluck(:category_id)
if muted_category_ids.present?
topics = topics.where("topics.category_id NOT IN (?)", muted_category_ids)
end
topics
end
# Using the digest query, figure out what's new for a user since last seen
def self.new_since_last_seen(user, since, featured_topic_ids)
topics = Topic.for_digest(user, since)
topics.where("topics.id NOT IN (?)", featured_topic_ids)
end
def meta_data=(data)
custom_fields.replace(data)
end
def meta_data
custom_fields
end
def update_meta_data(data)
custom_fields.update(data)
save
end
def reload(options=nil)
@post_numbers = nil
super(options)
end
def post_numbers
@post_numbers ||= posts.order(:post_number).pluck(:post_number)
end
def age_in_minutes
((Time.zone.now - created_at) / 1.minute).round
end
def has_meta_data_boolean?(key)
meta_data_string(key) == 'true'
end
def meta_data_string(key)
custom_fields[key.to_s]
end
def self.listable_count_per_day(sinceDaysAgo=30)
listable_topics.where('created_at > ?', sinceDaysAgo.days.ago).group('date(created_at)').order('date(created_at)').count
end
def private_message?
archetype == Archetype.private_message
end
# Search for similar topics
def self.similar_to(title, raw, user=nil)
return [] unless title.present?
return [] unless raw.present?
similar = Topic.select(sanitize_sql_array(["topics.*, similarity(topics.title, :title) + similarity(p.raw, :raw) AS similarity", title: title, raw: raw]))
.visible
.where(closed: false, archived: false)
.secured(Guardian.new(user))
.listable_topics
.joins("LEFT OUTER JOIN posts AS p ON p.topic_id = topics.id AND p.post_number = 1")
.limit(SiteSetting.max_similar_results)
.order('similarity desc')
# Exclude category definitions from similar topic suggestions
exclude_topic_ids = Category.pluck(:topic_id).compact!
if exclude_topic_ids.present?
similar = similar.where("topics.id NOT IN (?)", exclude_topic_ids)
end
similar
end
def update_status(status, enabled, user)
TopicStatusUpdate.new(self, user).update! status, enabled
end
# Atomically creates the next post number
def self.next_post_number(topic_id, reply = false)
highest = exec_sql("select coalesce(max(post_number),0) as max from posts where topic_id = ?", topic_id).first['max'].to_i
reply_sql = reply ? ", reply_count = reply_count + 1" : ""
result = exec_sql("UPDATE topics SET highest_post_number = ? + 1#{reply_sql}
WHERE id = ? RETURNING highest_post_number", highest, topic_id)
result.first['highest_post_number'].to_i
end
# If a post is deleted we have to update our highest post counters
def self.reset_highest(topic_id)
result = exec_sql "UPDATE topics
SET highest_post_number = (SELECT COALESCE(MAX(post_number), 0) FROM posts WHERE topic_id = :topic_id AND deleted_at IS NULL),
posts_count = (SELECT count(*) FROM posts WHERE deleted_at IS NULL AND topic_id = :topic_id),
last_posted_at = (SELECT MAX(created_at) FROM POSTS WHERE topic_id = :topic_id AND deleted_at IS NULL)
WHERE id = :topic_id
RETURNING highest_post_number", topic_id: topic_id
highest_post_number = result.first['highest_post_number'].to_i
# Update the forum topic user records
exec_sql "UPDATE topic_users
SET last_read_post_number = CASE
WHEN last_read_post_number > :highest THEN :highest
ELSE last_read_post_number
END,
seen_post_count = CASE
WHEN seen_post_count > :highest THEN :highest
ELSE seen_post_count
END
WHERE topic_id = :topic_id",
highest: highest_post_number,
topic_id: topic_id
end
# This calculates the geometric mean of the posts and stores it with the topic
def self.calculate_avg_time(min_topic_age=nil)
builder = SqlBuilder.new("UPDATE topics
SET avg_time = x.gmean
FROM (SELECT topic_id,
round(exp(avg(ln(avg_time)))) AS gmean
FROM posts
WHERE avg_time > 0 AND avg_time IS NOT NULL
GROUP BY topic_id) AS x
/*where*/")
builder.where("x.topic_id = topics.id AND
(topics.avg_time <> x.gmean OR topics.avg_time IS NULL)")
if min_topic_age
builder.where("topics.bumped_at > :bumped_at",
bumped_at: min_topic_age)
end
builder.exec
end
def changed_to_category(cat)
return true if cat.blank? || Category.find_by(topic_id: id).present?
Topic.transaction do
old_category = category
if category_id.present? && category_id != cat.id
Category.where(['id = ?', category_id]).update_all 'topic_count = topic_count - 1'
end
success = true
if self.category_id != cat.id
self.category_id = cat.id
success = save
end
if success
CategoryFeaturedTopic.feature_topics_for(old_category)
Category.where(id: cat.id).update_all 'topic_count = topic_count + 1'
CategoryFeaturedTopic.feature_topics_for(cat) unless old_category.try(:id) == cat.try(:id)
else
return false
end
end
true
end
def add_moderator_post(user, text, opts={})
new_post = nil
Topic.transaction do
creator = PostCreator.new(user,
raw: text,
post_type: Post.types[:moderator_action],
no_bump: opts[:bump].blank?,
topic_id: self.id)
new_post = creator.create
increment!(:moderator_posts_count)
new_post
end
if new_post.present?
# If we are moving posts, we want to insert the moderator post where the previous posts were
# in the stream, not at the end.
new_post.update_attributes(post_number: opts[:post_number], sort_order: opts[:post_number]) if opts[:post_number].present?
# Grab any links that are present
TopicLink.extract_from(new_post)
end
new_post
end
# Changes the category to a new name
def change_category(name)
# If the category name is blank, reset the attribute
if name.blank?
cat = Category.find_by(id: SiteSetting.uncategorized_category_id)
else
cat = Category.find_by(name: name)
end
return true if cat == category
return false unless cat
changed_to_category(cat)
end
def remove_allowed_user(username)
user = User.find_by(username: username)
if user
topic_user = topic_allowed_users.find_by(user_id: user.id)
if topic_user
topic_user.destroy
else
false
end
end
end
# Invite a user to the topic by username or email. Returns success/failure
def invite(invited_by, username_or_email, group_ids=nil)
if private_message?
# If the user exists, add them to the topic.
user = User.find_by_username_or_email(username_or_email)
if user && topic_allowed_users.create!(user_id: user.id)
# Notify the user they've been invited
user.notifications.create(notification_type: Notification.types[:invited_to_private_message],
topic_id: id,
post_number: 1,
data: { topic_title: title,
display_username: invited_by.username }.to_json)
return true
end
end
if username_or_email =~ /^.+@.+$/
# NOTE callers expect an invite object if an invite was sent via email
invite_by_email(invited_by, username_or_email, group_ids)
else
false
end
end
def invite_by_email(invited_by, email, group_ids=nil)
Invite.invite_by_email(email, invited_by, self, group_ids)
end
def email_already_exists_for?(invite)
invite.email_already_exists and private_message?
end
def grant_permission_to_user(lower_email)
user = User.find_by(email: lower_email)
topic_allowed_users.create!(user_id: user.id)
end
def max_post_number
posts.maximum(:post_number).to_i
end
def move_posts(moved_by, post_ids, opts)
post_mover = PostMover.new(self, moved_by, post_ids)
if opts[:destination_topic_id]
post_mover.to_topic opts[:destination_topic_id]
elsif opts[:title]
post_mover.to_new_topic(opts[:title], opts[:category_id])
end
end
# Updates the denormalized statistics of a topic including featured posters. They shouldn't
# go out of sync unless you do something drastic live move posts from one topic to another.
# this recalculates everything.
def update_statistics
feature_topic_users
update_action_counts
Topic.reset_highest(id)
end
def update_flagged_posts_count
PostAction.update_flagged_posts_count
end
def update_action_counts
PostActionType.types.keys.each do |type|
count_field = "#{type}_count"
update_column(count_field, Post.where(topic_id: id).sum(count_field))
end
end
def posters_summary(options = {})
@posters_summary ||= TopicPostersSummary.new(self, options).summary
end
def participants_summary(options = {})
@participants_summary ||= TopicParticipantsSummary.new(self, options).summary
end
# Enable/disable the star on the topic
def toggle_star(user, starred)
Topic.transaction do
TopicUser.change(user, id, {starred: starred}.merge( starred ? {starred_at: DateTime.now, unstarred_at: nil} : {unstarred_at: DateTime.now}))
# Update the star count
exec_sql "UPDATE topics
SET star_count = (SELECT COUNT(*)
FROM topic_users AS ftu
WHERE ftu.topic_id = topics.id
AND ftu.starred = true)
WHERE id = ?", id
if starred
StarLimiter.new(user).performed!
else
StarLimiter.new(user).rollback!
end
end
end
def make_banner!(user)
# only one banner at the same time
previous_banner = Topic.where(archetype: Archetype.banner).first
previous_banner.remove_banner!(user) if previous_banner.present?
self.archetype = Archetype.banner
self.add_moderator_post(user, I18n.t("archetypes.banner.message.make"))
self.save
MessageBus.publish('/site/banner', banner)
end
def remove_banner!(user)
self.archetype = Archetype.default
self.add_moderator_post(user, I18n.t("archetypes.banner.message.remove"))
self.save
MessageBus.publish('/site/banner', nil)
end
def banner
post = self.posts.order(:post_number).limit(1).first
{
html: post.cooked,
key: self.id
}
end
def self.starred_counts_per_day(sinceDaysAgo=30)
TopicUser.starred_since(sinceDaysAgo).by_date_starred.count
end
# Even if the slug column in the database is null, topic.slug will return something:
def slug
unless slug = read_attribute(:slug)
return '' unless title.present?
slug = Slug.for(title).presence || "topic"
if new_record?
write_attribute(:slug, slug)
else
update_column(:slug, slug)
end
end
slug
end
def title=(t)
slug = (Slug.for(t.to_s).presence || "topic")
write_attribute(:slug, slug)
write_attribute(:title,t)
end
# NOTE: These are probably better off somewhere else.
# Having a model know about URLs seems a bit strange.
def last_post_url
"/t/#{slug}/#{id}/#{posts_count}"
end
def self.url(id, slug, post_number=nil)
url = "#{Discourse.base_url}/t/#{slug}/#{id}"
url << "/#{post_number}" if post_number.to_i > 1
url
end
def url(post_number = nil)
self.class.url id, slug, post_number
end
def relative_url(post_number=nil)
url = "/t/#{slug}/#{id}"
url << "/#{post_number}" if post_number.to_i > 1
url
end
def clear_pin_for(user)
return unless user.present?
TopicUser.change(user.id, id, cleared_pinned_at: Time.now)
end
def re_pin_for(user)
return unless user.present?
TopicUser.change(user.id, id, cleared_pinned_at: nil)
end
def update_pinned(status, global=false)
update_column(:pinned_at, status ? Time.now : nil)
update_column(:pinned_globally, global)
end
def draft_key
"#{Draft::EXISTING_TOPIC}#{id}"
end
def notifier
@topic_notifier ||= TopicNotifier.new(self)
end
def muted?(user)
if user && user.id
notifier.muted?(user.id)
end
end
def auto_close_hours=(num_hours)
@ignore_category_auto_close = true
set_auto_close( num_hours )
end
def self.auto_close
Topic.where("NOT closed AND auto_close_at < ? AND auto_close_user_id IS NOT NULL", 1.minute.ago).each do |t|
t.auto_close
end
end
def auto_close(closer = nil)
if auto_close_at && !closed? && !deleted_at && auto_close_at < 5.minutes.from_now
closer ||= auto_close_user
if Guardian.new(closer).can_moderate?(self)
update_status('autoclosed', true, closer)
end
end
end
# Valid arguments for the auto close time:
# * An integer, which is the number of hours from now to close the topic.
# * A time, like "12:00", which is the time at which the topic will close in the current day
# or the next day if that time has already passed today.
# * A timestamp, like "2013-11-25 13:00", when the topic should close.
# * A timestamp with timezone in JSON format. (e.g., "2013-11-26T21:00:00.000Z")
# * nil, to prevent the topic from automatically closing.
def set_auto_close(arg, by_user=nil)
if arg.is_a?(String) && matches = /^([\d]{1,2}):([\d]{1,2})$/.match(arg.strip)
now = Time.zone.now
self.auto_close_at = Time.zone.local(now.year, now.month, now.day, matches[1].to_i, matches[2].to_i)
self.auto_close_at += 1.day if self.auto_close_at < now
elsif arg.is_a?(String) && arg.include?('-') && timestamp = Time.zone.parse(arg)
self.auto_close_at = timestamp
self.errors.add(:auto_close_at, :invalid) if timestamp < Time.zone.now
else
num_hours = arg.to_i
self.auto_close_at = (num_hours > 0 ? num_hours.hours.from_now : nil)
end
unless self.auto_close_at.nil?
self.auto_close_started_at ||= Time.zone.now
if by_user && by_user.staff?
self.auto_close_user = by_user
else
self.auto_close_user ||= (self.user.staff? ? self.user : Discourse.system_user)
end
else
self.auto_close_started_at = nil
end
self
end
def read_restricted_category?
category && category.read_restricted
end
def acting_user
@acting_user || user
end
def acting_user=(u)
@acting_user = u
end
def secure_group_ids
@secure_group_ids ||= if self.category && self.category.read_restricted?
self.category.secure_group_ids
end
end
def has_topic_embed?
TopicEmbed.where(topic_id: id).exists?
end
def expandable_first_post?
SiteSetting.embeddable_host.present? && SiteSetting.embed_truncate? && has_topic_embed?
end
private
def update_category_topic_count_by(num)
if category_id.present?
Category.where(['id = ?', category_id]).update_all("topic_count = topic_count " + (num > 0 ? '+' : '') + "#{num}")
end
end
def limit_first_day_topics_per_day
apply_per_day_rate_limit_for("first-day-topics", :max_topics_in_first_day)
end
def apply_per_day_rate_limit_for(key, method_name)
RateLimiter.new(user, "#{key}-per-day:#{Date.today.to_s}", SiteSetting.send(method_name), 1.day.to_i)
end
end
# == Schema Information
#
# Table name: topics
#
# id :integer not null, primary key
# title :string(255) not null
# last_posted_at :datetime
# created_at :datetime
# updated_at :datetime
# views :integer default(0), not null
# posts_count :integer default(0), not null
# user_id :integer
# last_post_user_id :integer not null
# reply_count :integer default(0), not null
# featured_user1_id :integer
# featured_user2_id :integer
# featured_user3_id :integer
# avg_time :integer
# deleted_at :datetime
# highest_post_number :integer default(0), not null
# image_url :string(255)
# off_topic_count :integer default(0), not null
# like_count :integer default(0), not null
# incoming_link_count :integer default(0), not null
# bookmark_count :integer default(0), not null
# star_count :integer default(0), not null
# category_id :integer
# visible :boolean default(TRUE), not null
# moderator_posts_count :integer default(0), not null
# closed :boolean default(FALSE), not null
# archived :boolean default(FALSE), not null
# bumped_at :datetime not null
# has_summary :boolean default(FALSE), not null
# vote_count :integer default(0), not null
# archetype :string(255) default("regular"), not null
# featured_user4_id :integer
# notify_moderators_count :integer default(0), not null
# spam_count :integer default(0), not null
# illegal_count :integer default(0), not null
# inappropriate_count :integer default(0), not null
# pinned_at :datetime
# score :float
# percent_rank :float default(1.0), not null
# notify_user_count :integer default(0), not null
# subtype :string(255)
# slug :string(255)
# auto_close_at :datetime
# auto_close_user_id :integer
# auto_close_started_at :datetime
# deleted_by_id :integer
# participant_count :integer default(1)
# word_count :integer
# excerpt :string(1000)
# pinned_globally :boolean default(FALSE), not null
#
# Indexes
#
# idx_topics_front_page (deleted_at,visible,archetype,category_id,id)
# idx_topics_user_id_deleted_at (user_id)
# index_topics_on_bumped_at (bumped_at)
# index_topics_on_id_and_deleted_at (id,deleted_at)
#