Class: Alien::AlienConnection

Inherits:
Object
  • Object
show all
Defined in:
lib/alien/alienconnection.rb

Direct Known Subclasses

AlienReader

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize ⇒ AlienConnection

Returns a new instance of AlienConnection.



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# File 'lib/alien/alienconnection.rb', line 19

def initialize
  @connected = false
  @raise_errors = true
end

Instance Attribute Details

#raise_errors ⇒ Object

Returns the value of attribute raise_errors.



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# File 'lib/alien/alienconnection.rb', line 17

def raise_errors
  @raise_errors
end

Instance Method Details

#close(send_quit = true) ⇒ Object

Close the socket.



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# File 'lib/alien/alienconnection.rb', line 172

def close(send_quit=true)
  if @connected
    if send_quit
      @sock.write("quit\r\n")
      sleep 1
    end
    @sock.close()
  end

  @connected = false
  return true
end

#connect(ipaddress = 'localhost', port = 23) ⇒ Object

Try to open a socket connection to the reader.



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# File 'lib/alien/alienconnection.rb', line 108

def connect(ipaddress='localhost', port=23)
  @connected = false

  #connect to a reader and grab the welcome message...
  begin
    timeout(3) {
      @sock = TCPSocket.new(ipaddress, port)
    }

    s = receive() #Grab the welcome message
    if s.include?("later.")  #Reader is busy. Please call back later.
      raise "Trouble Connecting to #{ipaddress}. (Someone else is talking to the reader.)"
    end
    @connected = true
  rescue RuntimeError
    raise
  rescue Timeout::Error, Errno::ETIMEDOUT
    raise "Trouble Connecting to #{ipaddress}. (No reader at this IP?)"
  rescue Errno::ECONNREFUSED
    raise "Trouble Connecting to #{ipaddress}. (Connection refused.)"
  end

  return @connected
end

#connected ⇒ Object

Returns the connected status of this AlienReader.



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# File 'lib/alien/alienconnection.rb', line 25

def connected
  return @connected
end

#open(ipaddress = "localhost", port = 23, username = "alien", password = "password") ⇒ Object

Execute both the connect and login methods in one call.



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# File 'lib/alien/alienconnection.rb', line 160

def open(ipaddress="localhost", port=23, username="alien", password="password")
  connect(ipaddress,port)

  if @connected
    (username,password)
  end

  return @connected
end

#receive(opts = {}) ⇒ Object

Read from the open socket until a null character is found. Strips off the trailing rn from the response



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# File 'lib/alien/alienconnection.rb', line 32

def receive(opts={})
  timeout = opts.fetch(:timeout, 40).to_i
  wait_for_null = opts.fetch(:wait_for_null, true)

  s = ""

  # Wait for data to become available on the socket
  res = select([@sock], nil, nil, timeout)
  if (res == nil)
    raise "Timeout waiting for reader response." if @raise_errors
  end

  if (wait_for_null)
    # Some readers don't put a null on the end of the 'call back later' message.
    # Check for 'later' to know when to punt on the read.
    begin
      timeout(timeout) {
        char = @sock.recv(1)
        while (char != "\0")
          s << char
          char = @sock.recv(1)
        end
      }
    rescue Timeout::Error
      raise "Timeout waiting for reader response." if @raise_errors
    end

    s.strip!

    if s.include? "Error"
      raise s if @raise_errors
    end

    # If this is a response to a Quit command, the reader will close the socket.
    # If there is an active connection, the reader will reject our attempt to connect.
    # Either way, we're not connected anymore...
    if (s.include? "Goodbye!")
      close(false)
    end

    return s
  else
    # Simply try to read up to 1 kB and return it
    return @sock.recv(1024)
  end
end

#send(msg = "") ⇒ Object

Send a message over an open socket (Alien terse msg format to suppress prompts on reply)



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# File 'lib/alien/alienconnection.rb', line 81

def send (msg="")
  if @connected
    @sock.write "\1#{msg}\r\n" # leading \1 for terse reply
  end
end

#sendreceive(msg = "", opts = {}) ⇒ Object

Send a message over an open socket and wait for a reply



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# File 'lib/alien/alienconnection.rb', line 89

def sendreceive(msg="", opts={})
  timeout = opts.fetch(:timeout, 40)
  wait_for_null = opts.fetch(:wait_for_null, true)

  begin
    if @connected
      send(msg)
      receive(:timeout=>timeout, :wait_for_null=>wait_for_null)
    else
      raise "Not connected to reader."
    end
  rescue
    err = "Error in alienconnection:\nTried to send:\"#{msg}\"\nand got:\n\"" + String($!) +"\""
    raise err
  end
end