Class: MessageBus::Client

Inherits:
Object
  • Object
show all
Defined in:
lib/message_bus/client.rb

Overview

Represents a connected subscriber and delivers published messages over its connected socket.

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(opts) ⇒ Client

Returns a new instance of Client.

Options Hash (opts):

  • :client_id (String) —

    the unique ID provided by the client

  • :user_id (String, Integer) — default: `nil` —

    the user ID the client was authenticated for

  • :group_ids (Array<String,Integer>) — default: `[]` —

    the group IDs the authenticated client is a member of

  • :site_id (String) — default: `nil` —

    the site ID the client was authenticated for; used for hosting multiple applications or instances of an application against a single message_bus

  • :seq (#to_i) — default: `0` —

    the connection sequence number the client provided when connecting

  • :message_bus (MessageBus::Instance) — default: `MessageBus` —

    a specific instance of message_bus



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# File 'lib/message_bus/client.rb', line 38

def initialize(opts)
  self.client_id = opts[:client_id]
  self.user_id = opts[:user_id]
  self.group_ids = opts[:group_ids] || []
  self.site_id = opts[:site_id]
  self.seq = opts[:seq].to_i
  self.connect_time = Time.now
  @lock = Mutex.new
  @bus = opts[:message_bus] || MessageBus
  @subscriptions = {}
  @chunks_sent = 0
  @async_response = nil
  @io = nil
  @wrote_headers = false
end

Instance Attribute Details

#async_response ⇒ Thin::AsyncResponse? 



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# File 'lib/message_bus/client.rb', line 20

def async_response
  @async_response
end

#cleanup_timer ⇒ MessageBus::TimerThread::Cancelable 



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# File 'lib/message_bus/client.rb', line 18

def cleanup_timer
  @cleanup_timer
end

#client_id ⇒ String 



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# File 'lib/message_bus/client.rb', line 7

def client_id
  @client_id
end

#connect_time ⇒ Time 



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# File 'lib/message_bus/client.rb', line 13

def connect_time
  @connect_time
end

#group_ids ⇒ Array<String,Integer> 



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# File 'lib/message_bus/client.rb', line 11

def group_ids
  @group_ids
end

#headers ⇒ Hash<String => String> 



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# File 'lib/message_bus/client.rb', line 24

def headers
  @headers
end

#io ⇒ IO 



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# File 'lib/message_bus/client.rb', line 22

def io
  @io
end

#seq ⇒ Integer 



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# File 'lib/message_bus/client.rb', line 26

def seq
  @seq
end

#site_id ⇒ String 



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# File 'lib/message_bus/client.rb', line 15

def site_id
  @site_id
end

#use_chunked ⇒ Boolean 



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# File 'lib/message_bus/client.rb', line 28

def use_chunked
  @use_chunked
end

#user_id ⇒ String, Integer 



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# File 'lib/message_bus/client.rb', line 9

def user_id
  @user_id
end

Instance Method Details

#<<(msg) ⇒ void

This method returns an undefined value.

Delivers a message to the client, even if it’s empty



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# File 'lib/message_bus/client.rb', line 121

def <<(msg)
  json = messages_to_json([msg])
  if use_chunked
    write_chunk json
  else
    write_and_close json
  end
end

#allowed?(msg) ⇒ Boolean 



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# File 'lib/message_bus/client.rb', line 133

def allowed?(msg)
  client_allowed = !msg.client_ids || msg.client_ids.length == 0 || msg.client_ids.include?(self.client_id)

  user_allowed = false
  group_allowed = false

  has_users = msg.user_ids && msg.user_ids.length > 0
  has_groups = msg.group_ids && msg.group_ids.length > 0

  if has_users
    user_allowed = msg.user_ids.include?(self.user_id)
  end

  if has_groups
    group_allowed = (
      msg.group_ids - (self.group_ids || [])
    ).length < msg.group_ids.length
  end

  has_permission = client_allowed && (user_allowed || group_allowed || (!has_users && !has_groups))

  return has_permission if !has_permission

  filters_allowed = true

  len = @bus.client_message_filters.length
  while len > 0
    len -= 1
    channel_prefix, blk = @bus.client_message_filters[len]

    if msg.channel.start_with?(channel_prefix)
      filters_allowed = blk.call(msg)
      break if !filters_allowed
    end
  end

  filters_allowed
end

#backlog ⇒ Array<MessageBus::Message> 



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# File 'lib/message_bus/client.rb', line 177

def backlog
  r = []
  new_message_ids = nil

  last_bus_ids = @bus.last_ids(*@subscriptions.keys, site_id: site_id)

  @subscriptions.each do |k, v|
    last_client_id = v.to_i
    last_bus_id = last_bus_ids[k]

    if last_client_id < -1 # Client requesting backlog relative to bus position
      last_client_id = last_bus_id + last_client_id + 1
      last_client_id = 0 if last_client_id < 0
    elsif last_client_id == -1 # Client not requesting backlog
      next
    elsif last_client_id == last_bus_id # Client already up-to-date
      next
    elsif last_client_id > last_bus_id # Client ahead of the bus
      @subscriptions[k] = -1
      next
    end

    messages = @bus.backlog(k, last_client_id, site_id)

    messages.each do |msg|
      if allowed?(msg)
        r << msg
      else
        new_message_ids ||= {}
        new_message_ids[k] = msg.message_id
      end
    end
  end

  # stats message for all newly subscribed
  status_message = nil
  @subscriptions.each do |k, v|
    if v.to_i == -1 || (new_message_ids && new_message_ids[k])
      status_message ||= {}
      @subscriptions[k] = status_message[k] = last_bus_ids[k]
    end
  end

  r << MessageBus::Message.new(-1, -1, '/__status', status_message) if status_message

  r || []
end

#close ⇒ Object

Closes the client connection



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# File 'lib/message_bus/client.rb', line 61

def close
  if cleanup_timer
    # concurrency may nil cleanup timer
    cleanup_timer.cancel rescue nil
    self.cleanup_timer = nil
  end
  ensure_closed!
end

#closed? ⇒ Boolean 



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# File 'lib/message_bus/client.rb', line 95

def closed?
  !@async_response && !@io
end

#deliver_backlog(backlog) ⇒ void

This method returns an undefined value.

Delivers a backlog of messages to the client, if there is anything in it. If chunked encoding/streaming is in use, will keep the connection open; if not, will close it.



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# File 'lib/message_bus/client.rb', line 76

def deliver_backlog(backlog)
  if backlog.length > 0
    if use_chunked
      write_chunk(messages_to_json(backlog))
    else
      write_and_close messages_to_json(backlog)
    end
  end
end

#ensure_first_chunk_sent ⇒ Object

If no data has yet been sent to the client, sends an empty chunk; prevents clients from entering a timeout state if nothing is delivered initially.



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# File 'lib/message_bus/client.rb', line 88

def ensure_first_chunk_sent
  if use_chunked && @chunks_sent == 0
    write_chunk("[]")
  end
end

#subscribe(channel, last_seen_id) ⇒ void

This method returns an undefined value.

Subscribes the client to messages on a channel, optionally from a defined starting point.



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# File 'lib/message_bus/client.rb', line 106

def subscribe(channel, last_seen_id)
  last_seen_id = nil if last_seen_id == ""
  last_seen_id ||= @bus.last_id(channel)
  @subscriptions[channel] = last_seen_id.to_i
end

#subscriptions ⇒ Hash<String => Integer> 



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# File 'lib/message_bus/client.rb', line 114

def subscriptions
  @subscriptions
end

#synchronize { ... } ⇒ void

This method returns an undefined value.

Yields:

  • executed with a lock on the Client instance



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# File 'lib/message_bus/client.rb', line 56

def synchronize
  @lock.synchronize { yield }
end