class T2Server::PortValue

A class to represent an output port data value.



The mime-type we use for an empty value. Note that an empty value is not simply an empty string. It is the complete absence of a value.


The mime-type we use for an error value.



The URI reference of this port value as a String.


The size (in bytes) of the port value.


The mime type of this port value as a String.

Public Instance Methods

empty? → true or false click to toggle source

Is this port value empty?

# File lib/t2-server/port.rb, line 531
def empty?
  @type == EMPTY_TYPE
error? → true or false click to toggle source

Does this port represent an error?

# File lib/t2-server/port.rb, line 523
def error?
inspect → string click to toggle source

Return a printable representation of this port value for debugging purposes.

# File lib/t2-server/port.rb, line 543
def inspect
  @@to_s.bind(self).call.sub!(/>\z/) { " @value=#{value.inspect}, " +
    "@type=#{type.inspect}, @size=#{size.inspect}>"
stream_value(stream) → fixnum click to toggle source
stream_value(stream, range) → fixnum

Stream this port value directly into another stream. The stream passed in may be anything that provides a write method; instances of IO and File, for example. No data is cached by this method.

The number of bytes written to the stream is returned.

# File lib/t2-server/port.rb, line 492
def stream_value(stream, range = nil)
  raise ArgumentError,
    "Stream passed in must provide a write method" unless
      stream.respond_to? :write

  bytes = 0

  value(range) do |chunk|
    bytes += stream.write(chunk)

value → binary blob click to toggle source
value(range) → binary blob
value {|chunk| ...}
value(range) {|chunk| ...}

Get the value of this port from the server.

If no parameters are supplied then this method will simply download and return all the data.

Passing in a block will allow access to the underlying data stream so the data is not stored in memory:

run.output_port("port") do |chunk|
  print chunk

In both cases supplying a Range will download and return the data in that range.

This method does not cache any data.

If this port is an error then this value will be the error message.

# File lib/t2-server/port.rb, line 461
def value(range = nil, &block)
  # The following block is a workaround for Taverna Server versions prior
  # to 2.4.1 and can be removed when support for those versions is no
  # longer required.
  if error? && @size == 0
    value =
    @size = value.size
    range = 0...@size if range.nil? || range.min.nil?
    return value[range]

  return "" if @type == EMPTY_TYPE

  # Check that the range provided is sensible
  unless range.nil?
    range = 0..range.max if range.min < 0
    range = range.min...@size if range.max >= @size
  end, range, &block)
write_value_to_file(filename) → fixnum click to toggle source
write_value_to_file(filename, range) → fixnum

Stream this port value directly to a file. If a range is supplied then just that range of data is downloaded from the server. No data is cached by this method.

# File lib/t2-server/port.rb, line 513
def write_value_to_file(filename, range = nil), "wb") do |file|
    stream_value(file, range)