Class: ClientWorldModel

Inherits:
Object
  • Object
show all
Defined in:
lib/libowl/client_world_model.rb

Overview

This class abstracts the network details of connecting to a World Model. However, this class does not use a thread to handle networking in the background as in the ClientWorldConnection class, so handleMessage must be called manually. If threads are available then the ClientWorldConnection class is simpler to use.

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(host, port, data_callback = nil, uri_response_callback = nil) ⇒ ClientWorldModel

Returns a new instance of ClientWorldModel.



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# File 'lib/libowl/client_world_model.rb', line 49

def initialize(host, port, data_callback = nil, uri_response_callback = nil)
  @connected = false
  @host = host
  @port = port
  @socket = TCPSocket.open(host, port)
  handshake = ""
  ver_string = "GRAIL client protocol"
  #The handshake is the length of the message, the protocol string, and the version (0).
  handshake << [ver_string.length].pack('N') << ver_string << "\x00\x00"
  #Send a handshake and then receive one
  @socket.send(handshake, 0)
  inshake = @socket.recvfrom(handshake.length)[0]
  while (inshake.length < handshake.length)
    #puts "Waiting for #{handshake.length - inshake.length} byte more of handshake."
    inshake += @socket.recvfrom(handshake.length - inshake.length)[0]
  end

  @connected = true
  for i in 1..handshake.length
    if handshake[i] != inshake[i]
      puts "Handshake failure!"
      puts "For byte i we sent #{handshake[i]} but got #{inshake[i]}"
      @connected = false
    end
  end

  @alias_to_attr_name = {}
  @alias_to_origin_name = {}

  @data_callback = data_callback
  @uri_response_callback = uri_response_callback
end

Instance Attribute Details

#alias_to_attr_name ⇒ Object

Returns the value of attribute alias_to_attr_name.



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# File 'lib/libowl/client_world_model.rb', line 40

def alias_to_attr_name
  @alias_to_attr_name
end

#alias_to_origin_name ⇒ Object

Returns the value of attribute alias_to_origin_name.



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# File 'lib/libowl/client_world_model.rb', line 40

def alias_to_origin_name
  @alias_to_origin_name
end

#connected ⇒ Object (readonly)

Returns the value of attribute connected.



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# File 'lib/libowl/client_world_model.rb', line 41

def connected
  @connected
end

Instance Method Details

#close ⇒ Object 



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# File 'lib/libowl/client_world_model.rb', line 82

def close()
  @socket.close()
  @connected = false
end

#decodeAttributeAlias(inbuff) ⇒ Object

Decode attribute alias message



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# File 'lib/libowl/client_world_model.rb', line 121

def decodeAttributeAlias(inbuff)
  num_aliases = inbuff.unpack('N')[0]
  rest = inbuff[4, inbuff.length - 1]
  for i in 1..num_aliases do
    attr_alias = rest.unpack('N')[0]
    name, rest = splitURIFromRest(rest[4, rest.length - 1])
    #Assign this name to the given alias
    @alias_to_attr_name[attr_alias] = name
  end
end

#decodeDataResponse(inbuff) ⇒ Object 



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# File 'lib/libowl/client_world_model.rb', line 161

def decodeDataResponse(inbuff)
  attributes = []
  object_uri, rest = splitURIFromRest(inbuff)
  ticket = rest.unpack('N')[0]
  total_attributes = rest[4, rest.length - 1].unpack('N')[0]
  rest = rest[8, rest.length]
  #puts "Decoding #{total_attributes} attributes"
  for i in 1..total_attributes do
    name_alias = rest.unpack('N')[0]
    creation_date = unpackuint64(rest[4, rest.length - 1])
    expiration_date = unpackuint64(rest[12, rest.length - 1])
    origin_alias = rest[20, rest.length - 1].unpack('N')[0]
    data_len = rest[24, rest.length - 1].unpack('N')[0]
    data = rest[28, data_len]
    rest = rest[28+data_len, rest.length - 1]
    attributes.push(WMAttribute.new(@alias_to_attr_name[name_alias], data, creation_date, expiration_date, @alias_to_origin_name[origin_alias]))
  end
  return WMData.new(object_uri, attributes, ticket)
end

#decodeOriginAlias(inbuff) ⇒ Object

Decode origin alias message



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# File 'lib/libowl/client_world_model.rb', line 133

def decodeOriginAlias(inbuff)
  num_aliases = inbuff.unpack('N')[0]
  rest = inbuff[4, inbuff.length - 1]
  for i in 1..num_aliases do
    origin_alias = rest.unpack('N')[0]
    name, rest = splitURIFromRest(rest[4, rest.length - 1])
    #Assign this name to the given alias
    @alias_to_origin_name[origin_alias] = name
  end
end

#decodeTicketMessage(inbuff) ⇒ Object

Decode a ticket message or a request complete message.



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# File 'lib/libowl/client_world_model.rb', line 145

def decodeTicketMessage(inbuff)
  return inbuff.unpack('N')[0]
end

#decodeURIResponse(inbuff) ⇒ Object 



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# File 'lib/libowl/client_world_model.rb', line 149

def decodeURIResponse(inbuff)
  uris = []
  if (inbuff != nil)
    rest = inbuff
    while (rest.length > 4)
      name, rest = splitURIFromRest(rest)
      uris.push(name)
    end
  end
  return uris
end

#handleMessage ⇒ Object

Handle a message of currently unknown type



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# File 'lib/libowl/client_world_model.rb', line 88

def handleMessage()
  #puts "Handling message..."
  #Get the message length as n unsigned integer
  inlen = (@socket.recvfrom(4)[0]).unpack('N')[0]
  inbuff = @socket.recvfrom(inlen)[0]
  #Keep reading until the entire packet is read
  #TODO This can block forever if a communication error occurs.
  while (inbuff.length < inlen) 
    inbuff += @socket.recvfrom(inlen-inbuff.length)[0]
  end
  #Byte that indicates message type
  control = inbuff.unpack('C')[0]
  if control == ATTRIBUTE_ALIAS
    decodeAttributeAlias(inbuff[1, inbuff.length - 1])
  elsif control == ORIGIN_ALIAS
    decodeOriginAlias(inbuff[1, inbuff.length - 1])
  elsif control == REQUEST_COMPLETE
    ticket = decodeTicketMessage(inbuff[1, inbuff.length-1])
    #puts "World Model completed request for ticket #{ticket}"
  elsif control == DATA_RESPONSE
    if (@data_callback != nil)
      @data_callback.call(decodeDataResponse(inbuff[1, inbuff.length - 1]))
    end
  elsif control == URI_RESPONSE
    if (@uri_response_callback != nil)
      @uri_response_callback.call(decodeURIResponse(inbuff[1, inbuff.length - 1]))
    end
  end
  #puts "processed message with id #{control}"
  return control
end

#sendRangeRequest(name_pattern, attribute_patterns, ticket, start_time, stop_time) ⇒ Object 



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# File 'lib/libowl/client_world_model.rb', line 199

def sendRangeRequest(name_pattern, attribute_patterns, ticket, start_time, stop_time)
  buff = [RANGE_REQUEST].pack('C')

  buff += [ticket].pack('N')
  buff += strToSizedUTF16(name_pattern)
  buff += [attribute_patterns.length].pack('N')

  attribute_patterns.each{|pattern|
    buff += strToSizedUTF16(pattern)
  }

  buff += packuint64(start_time)
  buff += packuint64(stop_time)

  #Send the message with its length prepended to the front
  @socket.send("#{[buff.length].pack('N')}#{buff}", 0)
end

#sendSnapshotRequest(name_pattern, attribute_patterns, ticket, start_time = 0, stop_time = 0) ⇒ Object 



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# File 'lib/libowl/client_world_model.rb', line 181

def sendSnapshotRequest(name_pattern, attribute_patterns, ticket, start_time = 0, stop_time = 0)
  buff = [SNAPSHOT_REQUEST].pack('C')

  buff += [ticket].pack('N')
  buff += strToSizedUTF16(name_pattern)
  buff += [attribute_patterns.length].pack('N')

  attribute_patterns.each{|pattern|
    buff += strToSizedUTF16(pattern)
  }

  buff += packuint64(start_time)
  buff += packuint64(stop_time)

  #Send the message with its length prepended to the front
  @socket.send("#{[buff.length].pack('N')}#{buff}", 0)
end

#sendStreamRequest(name_pattern, attribute_patterns, update_interval, ticket) ⇒ Object 



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# File 'lib/libowl/client_world_model.rb', line 217

def sendStreamRequest(name_pattern, attribute_patterns, update_interval, ticket)
  buff = [STREAM_REQUEST].pack('C')

  buff += [ticket].pack('N')
  buff += strToSizedUTF16(name_pattern)
  buff += [attribute_patterns.length].pack('N')

  attribute_patterns.each{|pattern|
    buff += strToSizedUTF16(pattern)
  }

  buff += packuint64(0)
  buff += packuint64(update_interval)

  #Send the message with its length prepended to the front
  @socket.send("#{[buff.length].pack('N')}#{buff}", 0)
end

#sendURISearch(name_pattern) ⇒ Object 



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# File 'lib/libowl/client_world_model.rb', line 235

def sendURISearch(name_pattern)
  buff = [URI_SEARCH].pack('C')
  buff += strToUnicode(name_pattern)
  #Send the message with its length prepended to the front
  @socket.send("#{[buff.length].pack('N')}#{buff}", 0)
end