Class ProtocolStack
In: lib/network/protocol/protocolstack.rb
Parent: Object
ProtocolStack dot/f_34.png

The ProtocolStack class implements a stack of input and output filters. It also maintains some interesting state variables that are shared amongst filters.

Remarks:This should have its own configuration file.

Methods

filter_call   new   query   set  

Attributes

binary_on  [RW] 
color_on  [RW] 
conn  [R] 
echo_on  [RW] 
eorec_on  [RW] 
hide_on  [RW] 
terminal  [RW] 
theight  [RW] 
twidth  [RW] 
urgent_on  [RW] 
zmp_on  [RW] 

Public Class methods

new(conn)

Construct a ProtocolStack

conn
The connection associated with this filter

[Source]

# File lib/network/protocol/protocolstack.rb, line 38
  def initialize(conn)
    @conn = conn
    @server = @conn.server
    @filters = []  # Filter order is critical as lowest level protocol is first.
    if @server.service_filters.include? :debugfilter
      @filters << DebugFilter.new(self)
    end
    if @server.service_filters.include? :telnetfilter
      @filters << TelnetFilter.new(self,@server)
    end
    if @server.service_filters.include? :terminalfilter
      @filters << TerminalFilter.new(self)
    end
    if @server.service_filters.include? :colorfilter
      @filters << ColorFilter.new(self)
    end
    if @server.service_filters.include? :filter
      @filters << Filter.new(self)
    end

    # Shared variables to facilitate inter-filter communication.
    @sga_on = false
    @echo_on = false
    @binary_on = false
    @zmp_on = false
    @eorec_on = false
    @color_on = false
    @urgent_on = false
    @hide_on = false
    @terminal = nil
    @twidth = 80
    @theight = 23
  end

Public Instance methods

filter_call(method, args)

A method is called on each filter in the stack in order.

[method] [args]

[Source]

# File lib/network/protocol/protocolstack.rb, line 76
  def filter_call(method, args)
    case method
    when :filter_in, :init
      retval = args
      @filters.each do |v|
        retval = v.send(method,retval)
      end
    when :filter_out
      retval = args
      @filters.reverse_each do |v|
        retval = v.send(method,retval)
      end
    else
      log.error "(#{self.object_id}) ProtocolStack#filter_call unknown method '#{method}',a:#{args.inspect},r:#{retval.inspect}"
    end
    retval
  end
query(attr)

The filter_query method returns state information for the filter.

attr
A symbol representing the attribute being queried.
return
An attr/value pair or false if not defined in this filter

[Source]

# File lib/network/protocol/protocolstack.rb, line 97
  def query(attr)
    case attr
    when :terminal
      retval =  @terminal
    when :termsize
      retval =  [@twidth, @theight]
    when :color
      retval =  @color_on
    when :zmp
      retval =  @zmp_on
    when :echo
      retval =  @echo_on
    when :binary
      retval =  @binary_on
    when :eorec
      retval =  @eorec_on
    when :urgent
      retval =  @urgent_on
    when :hide
      retval =  @hide_on
    when :ip
      retval =  @conn.addr
    when :host
      retval =  @conn.host
    else
      log.error "(#{self.object_id}) ProtocolStack#query unknown setting '#{pair.inspect}'"
      retval = false
    end
    log.debug "(#{self.object_id}) ProtocolStack#query called '#{attr}',r:#{retval.inspect}"
    retval
  end
set(attr, value)

The filter_set method sets state information on the filter.

pair
An attr/value pair [:symbol, value]
return
true if attr not defined in this filter, false if not

[Source]

# File lib/network/protocol/protocolstack.rb, line 132
  def set(attr, value)
    case attr
    when :color
      @color_on = value
      true
    when :urgent
      @urgent_on = value
      true
    when :hide
      @hide_on = value
      true
    when :terminal
      @terminal = value
      true
    when :termsize
      @twidth = value[0]
      @theight = value[1]
      # telnet filter always first except when debugfilter on
      if @server.service_filters.include? :telnetfilter
        if @server.service_filters.include? :debugfilter
          @filters[1].send_naws
        else
          @filters[0].send_naws
        end
      end
      true
    when :init_subneg
      # telnet filter always first except when debugfilter on
      if @server.service_filters.include? :telnetfilter
        if @server.service_filters.include? :debugfilter
          @filters[1].init_subneg
        else
          @filters[0].init_subneg
        end
      end
      true
    else
      log.error "(#{self.object_id}) ProtocolStack#set unknown setting '#{attr}=#{value}'"
      false
    end
    log.debug "(#{self.object_id}) ProtocolStack#set called '#{attr}=#{value}'"
  end

[Validate]