Class: RBus::Auth::StateMachine

Inherits:
Object
  • Object
show all
Defined in:
lib/rbus/auth/state_machine.rb

Overview

Implements a statemachine for Authorization like the one described in the D-Bus specification.

Instance Method Summary collapse

Constructor Details

#initialize(transport) ⇒ StateMachine

Returns a new instance of StateMachine.



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# File 'lib/rbus/auth/state_machine.rb', line 30

def initialize(transport)
  @transport = transport
  @mechanism = FIRST_MECHANISM.new
end

Dynamic Method Handling

This class handles dynamic methods through the method_missing method

#method_missing(symbol, *args) ⇒ Object

send_begin => BEGIN, etc



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# File 'lib/rbus/auth/state_machine.rb', line 139

def method_missing(symbol, *args)
  command = symbol.to_s
  if command.sub!('send_', '')
    line = [command.upcase, hex_encode(args[0])].compact.join(' ')
    @transport.sendline(line)          
  end
end

Instance Method Details

#authorize ⇒ Object

Main entry point, returns guid if succesful, or raises otherwise.



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# File 'lib/rbus/auth/state_machine.rb', line 36

def authorize        
  state = :AUTH
  
  loop do
    case state
      when :AUTH
        command, data, state = @mechanism.auth
        send_auth(command, data)
        
      when :REJECTED
        response = Command.new(@transport.readline)
        case response.command
          when 'REJECTED'
            next_mechanism(response.data)
            state = :AUTH
          else
            raise AuthException
        end 

      when :OK
        response = Command.new(@transport.readline)
        case response.command
          when 'OK'
            send_begin
            return response.data
          when 'REJECTED'
            next_mechanism(response.data)
            state = :AUTH
          when 'DATA'
            send_cancel
            state = :REJECTED
          when 'ERROR'
            send_cancel
            state = :REJECTED
          else
            send_error
            state = :OK
        end

      when :DATA
        response = Command.new(@transport.readline)
        case response.command
          when 'DATA'
            begin
              message, state = @mechanism.data(response.data)
            rescue AuthException => e
              send_cancel
              state = :REJECTED
            else
              send_data(message)
            end
          when 'REJECTED'
            next_mechanism(response.data)
            state = :AUTH
          when 'ERROR'
            send_cancel
            state = :REJECTED
          when 'OK'
            send_begin
            return response.data
          else
            send_error
            state = :DATA
        end
      else
        raise
    end
  end
end

#hex_encode(plain) ⇒ Object

Server expects all data to be encoded in hex



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# File 'lib/rbus/auth/state_machine.rb', line 148

def hex_encode(plain)
  return nil if plain.nil?
  plain.to_s.unpack('H*')[0]
end

#next_mechanism(data) ⇒ Object

Move to next mechanism



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# File 'lib/rbus/auth/state_machine.rb', line 107

def next_mechanism(data)
  if @mechanisms.nil?
    populate_mechanisms(data)
  end
  if @mechanisms.empty?
    raise AuthException
  else
    @mechanism = @mechanisms.shift.new
  end
end

#populate_mechanisms(data) ⇒ Object

Build initial mechanism list



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# File 'lib/rbus/auth/state_machine.rb', line 119

def populate_mechanisms(data)
  server_mechanisms = data.split(' ')
  
  # Find common mechanisms, or try them all if server didn't tell us
  if server_mechanisms.empty?
    mechanisms = MECHANISMS.keys
  else
    mechanisms = (server_mechanisms & MECHANISMS.keys)
  end
  
  @mechanisms = mechanisms.map{|name| MECHANISMS[name]}
end

#send_auth(command, data) ⇒ Object

Send AUTH …



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# File 'lib/rbus/auth/state_machine.rb', line 133

def send_auth(command, data)
  line = ['AUTH', command, hex_encode(data)].compact.join(' ')
  @transport.sendline(line)
end