Module: UrlTracker::SocketCommunication

Included in:
Client, Server
Defined in:
lib/url_tracker/socket_communication.rb

Overview

Implements communication via Unix sockets.

Constant Summary collapse

InvalidSocketError = 
Class.new(StandardError)
MAX_MESSAGE_LENGTH =

Messages received cannot be longer than 1024 bytes

1024
MAX_CONN_QUEUE =

Max connections to be queued before accept

10

Instance Attribute Summary collapse

Instance Method Summary collapse

Instance Attribute Details

#path=(value) ⇒ Object (writeonly)

path to the socket file



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# File 'lib/url_tracker/socket_communication.rb', line 7

def path=(value)
  @path = value
end

Instance Method Details

#bind(path) ⇒ Object

Binds the given path, creating a Unix socket. As with connect, you cannot use this method if already called connect before. After this method is called, the socket will be waiting for connections.



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# File 'lib/url_tracker/socket_communication.rb', line 30

def bind(path)
  raise_socket_error_if { defined? @socket }
  @socket_file = path
  @socket = Socket.new(:UNIX, :SOCK_STREAM, 0)
  @socket.bind addrinfo_for(@socket_file)
  @socket.listen(MAX_CONN_QUEUE)
  true
end

#close_connection ⇒ Object 



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# File 'lib/url_tracker/socket_communication.rb', line 58

def close_connection
  defined?(@socket) && !@socket.closed? && @socket.close
  File.unlink(@socket_file) if defined?(@socket_file) && File.exists?(@socket_file)
end

#connect(path) ⇒ Object

Connects to the Unix socket. Returns true if the connection was successful. Otherwise an exception is thrown. This method cannot be called if bind was already called; neither can you call bind if you call this method.



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# File 'lib/url_tracker/socket_communication.rb', line 20

def connect(path)
  raise_socket_error_if { defined? @socket }
  @socket = Socket.new(:UNIX, :SOCK_STREAM, 0)
  @socket.connect addrinfo_for(path)
  true
end

#next_message ⇒ Object

Waits for a message. Blocks until it is received.



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# File 'lib/url_tracker/socket_communication.rb', line 53

def next_message
  socket = (defined? @current_client) ? @current_client : @socket
  socket.recvfrom(MAX_MESSAGE_LENGTH).first
end

#wait_for_connection ⇒ Object

Waits for a connection in the binded socket



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# File 'lib/url_tracker/socket_communication.rb', line 40

def wait_for_connection
  @current_client = @socket.accept.first
end

#write(message) ⇒ Object

Writes to the socket, returning the number of bytes sent. This method can only be called before connect or wait_for_connection, otherwise you will get an exception



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# File 'lib/url_tracker/socket_communication.rb', line 47

def write(message)
  socket = (defined? @current_client) ? @current_client : @socket
  socket.send(message, 0)
end