Class: PrivateMessageTopicTrackingState

Inherits:
Object
  • Object
show all
Includes:
TopicTrackingStatePublishable
Defined in:
app/models/private_message_topic_tracking_state.rb

Overview

This class is used to mirror unread and new status for private messages between server and client.

On the server side, this class has two main responsibilities. The first is to query the database for the initial state of a user’s unread and new private messages. The second is to publish message_bus messages to notify the client of various topic events.

On the client side, we have a ‘PrivateMessageTopicTrackingState` class as well which will load the initial state into memory and subscribes to the relevant message_bus messages. When a message is received, it modifies the in-memory state based on the message type. The filtering for new and unread topics is done on the client side based on the in-memory state in order to derive the count of new and unread topics efficiently.

Constant Summary collapse

CHANNEL_PREFIX = 
"/private-message-topic-tracking-state"
NEW_MESSAGE_TYPE = 
"new_topic"
UNREAD_MESSAGE_TYPE = 
"unread"
READ_MESSAGE_TYPE = 
"read"
GROUP_ARCHIVE_MESSAGE_TYPE = 
"group_archive"

Class Method Summary collapse

Class Method Details

.group_channel(group_id) ⇒ Object 



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# File 'app/models/private_message_topic_tracking_state.rb', line 210

def self.group_channel(group_id)
  "#{CHANNEL_PREFIX}/group/#{group_id}"
end

.new_and_unread_sql(user) ⇒ Object 



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# File 'app/models/private_message_topic_tracking_state.rb', line 38

def self.new_and_unread_sql(user)
  sql = report_raw_sql(user, skip_unread: true)
  sql << "\nUNION ALL\n\n"
  sql << report_raw_sql(user, skip_new: true)
end

.publish_group_archived(topic:, group_id:, acting_user_id: nil) ⇒ Object 



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# File 'app/models/private_message_topic_tracking_state.rb', line 180

def self.publish_group_archived(topic:, group_id:, acting_user_id: nil)
  return unless topic.private_message?

  message = {
    message_type: GROUP_ARCHIVE_MESSAGE_TYPE,
    topic_id: topic.id,
    payload: {
      group_ids: [group_id],
      acting_user_id: acting_user_id,
    },
  }.as_json

  MessageBus.publish(self.group_channel(group_id), message, group_ids: [group_id])
end

.publish_new(topic) ⇒ Object 



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# File 'app/models/private_message_topic_tracking_state.rb', line 151

def self.publish_new(topic)
  return unless topic.private_message?

  message = {
    message_type: NEW_MESSAGE_TYPE,
    topic_id: topic.id,
    payload: {
      last_read_post_number: nil,
      highest_post_number: 1,
      group_ids: topic.allowed_groups.pluck(:id),
      created_by_user_id: topic.user_id,
    },
  }.as_json

  topic
    .allowed_users
    .pluck(:id)
    .each do |user_id|
      MessageBus.publish(self.user_channel(user_id), message, user_ids: [user_id])
    end

  topic
    .allowed_groups
    .pluck(:id)
    .each do |group_id|
      MessageBus.publish(self.group_channel(group_id), message, group_ids: [group_id])
    end
end

.publish_read(topic_id, last_read_post_number, user, notification_level = nil) ⇒ Object 



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# File 'app/models/private_message_topic_tracking_state.rb', line 195

def self.publish_read(topic_id, last_read_post_number, user, notification_level = nil)
  self.publish_read_message(
    message_type: READ_MESSAGE_TYPE,
    channel_name: self.user_channel(user.id),
    topic_id: topic_id,
    user: user,
    last_read_post_number: last_read_post_number,
    notification_level: notification_level,
  )
end

.publish_unread(post) ⇒ Object 



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# File 'app/models/private_message_topic_tracking_state.rb', line 98

def self.publish_unread(post)
  topic = post.topic
  return unless topic.private_message?

  scope = TopicUser.tracking(post.topic_id).includes(user: %i[user_stat user_option])

  allowed_group_ids = topic.allowed_groups.pluck(:id)

  group_ids =
    if post.post_type == Post.types[:whisper]
      [Group::AUTO_GROUPS[:staff]]
    else
      allowed_group_ids
    end

  if group_ids.present?
    scope =
      scope.joins("INNER JOIN group_users gu ON gu.user_id = topic_users.user_id").where(
        "gu.group_id IN (?)",
        group_ids,
      )
  end

  # Note: At some point we may want to make the same peformance optimisation
  # here as we did with the other topic tracking state, where we only send
  # one 'unread' update to all users, not a more accurate unread update to
  # each individual user with their own read state.
  #
  # cf. f6c852bf8e7f4dea519425ba87a114f22f52a8f4
  scope
    .select(%i[user_id last_read_post_number notification_level])
    .each do |tu|
      if tu.last_read_post_number.nil? &&
           topic.created_at < tu.user.user_option.treat_as_new_topic_start_date
        next
      end

      message = {
        topic_id: post.topic_id,
        message_type: UNREAD_MESSAGE_TYPE,
        payload: {
          last_read_post_number: tu.last_read_post_number,
          highest_post_number: post.post_number,
          notification_level: tu.notification_level,
          group_ids: allowed_group_ids,
          created_by_user_id: post.user_id,
        },
      }

      MessageBus.publish(self.user_channel(tu.user_id), message.as_json, user_ids: [tu.user_id])
    end
end

.report(user) ⇒ Object 



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# File 'app/models/private_message_topic_tracking_state.rb', line 26

def self.report(user)
  sql = new_and_unread_sql(user)

  DB.query(
    sql + "\n\n LIMIT :max_topics",
    {
      max_topics: TopicTrackingState::MAX_TOPICS,
      min_new_topic_date: Time.at(SiteSetting.min_new_topics_time).to_datetime,
    },
  )
end

.report_raw_sql(user, skip_unread: false, skip_new: false) ⇒ Object 



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# File 'app/models/private_message_topic_tracking_state.rb', line 44

def self.report_raw_sql(user, skip_unread: false, skip_new: false)
  unread =
    if skip_unread
      "1=0"
    else
      first_unread_pm_at = DB.query_single(<<~SQL, user_id: user.id).first
      SELECT
        LEAST(
          MIN(user_stats.first_unread_pm_at),
          MIN(group_users.first_unread_pm_at)
        )
      FROM group_users
      JOIN groups ON groups.id = group_users.group_id
      JOIN user_stats ON user_stats.user_id = :user_id
      WHERE group_users.user_id = :user_id;
      SQL

      <<~SQL
      #{TopicTrackingState.unread_filter_sql(whisperer: user.whisperer?)}
      #{first_unread_pm_at ? "AND topics.updated_at > '#{first_unread_pm_at}'" : ""}
      SQL
    end

  new =
    if skip_new
      "1=0"
    else
      TopicTrackingState.new_filter_sql
    end

  sql = +<<~SQL
    SELECT
      DISTINCT topics.id AS topic_id,
      u.id AS user_id,
      last_read_post_number,
      tu.notification_level,
      #{TopicTrackingState.highest_post_number_column_select(user.whisperer?)},
      ARRAY(SELECT group_id FROM topic_allowed_groups WHERE topic_allowed_groups.topic_id = topics.id) AS group_ids
    FROM topics
    JOIN users u on u.id = #{user.id.to_i}
    JOIN user_stats AS us ON us.user_id = u.id
    JOIN user_options AS uo ON uo.user_id = u.id
    LEFT JOIN group_users gu ON gu.user_id = u.id
    LEFT JOIN topic_allowed_groups tag ON tag.topic_id = topics.id AND tag.group_id = gu.group_id
    LEFT JOIN topic_users tu ON tu.topic_id = topics.id AND tu.user_id = u.id
    LEFT JOIN topic_allowed_users tau ON tau.topic_id = topics.id AND tau.user_id = u.id
    #{skip_new ? "" : "LEFT JOIN dismissed_topic_users ON dismissed_topic_users.topic_id = topics.id AND dismissed_topic_users.user_id = #{user.id.to_i}"}
    WHERE (tau.topic_id IS NOT NULL OR tag.topic_id IS NOT NULL) AND
      topics.archetype = 'private_message' AND
      ((#{unread}) OR (#{new})) AND
      topics.deleted_at IS NULL
  SQL
end

.user_channel(user_id) ⇒ Object 



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# File 'app/models/private_message_topic_tracking_state.rb', line 206

def self.user_channel(user_id)
  "#{CHANNEL_PREFIX}/user/#{user_id}"
end