Class: Mikrotik::Protocol::Parser

Inherits:
Object
  • Object
show all
Defined in:
lib/mikrotik/protocol/parser.rb

Overview

Responsible for extracting replies from API sentence data

Constant Summary

PAIR = 
/^(.+)=(.+)$/

Instance Method Summary (collapse)

Constructor Details

- (Parser) initialize

A new instance of Parser



9
10
11
12
13
 
# File 'lib/mikrotik/protocol/parser.rb', line 9

def initialize
  @data = ''
  @data.force_encoding(Encoding::BINARY) if RUBY_VERSION > '1.9'
  reset!
end

Instance Method Details

- (Object) <<(data)

Adds data to the parser buffer and runs the parser



21
22
23
24
25
 
# File 'lib/mikrotik/protocol/parser.rb', line 21

def <<(data)
  @data << data
  success = true
  success = get_sentence while success
end

- (Object) bytes(bits) 



122
123
124
 
# File 'lib/mikrotik/protocol/parser.rb', line 122

def bytes(bits)
  (bits / 8.0).ceil
end

- (Object) get_length 



54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
 
# File 'lib/mikrotik/protocol/parser.rb', line 54

def get_length
  size = get_length_size

  return false unless size

  need = bytes(size + 1)
  return false unless @data.size >= need

  length = nil
  field = @data[0, need].unpack('C*')

  case size
    when 7
      length = field[0] & 0x7f
    when 14
      length = ((field[0] & 0x3f) <<  8) | field[1]
    when 21
      length = ((field[0] & 0x1f) << 16) | field[1] <<  8 | field[2]
    when 28
      length = ((field[0] & 0x0f) << 24) | field[1] << 16 | field[2] << 8 | field[3]
    when 32
      length = field[1..4].pack('C4').unpack('N').first
  end

  if length
    return length
  else
    raise ArgumentError, "Invalid word length"
  end
end

- (Object) get_length_size

Indentifies the size of the length field in bits

Returns:

  • boolean, integer

Raises:

  • (ArgumentError) 


31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
 
# File 'lib/mikrotik/protocol/parser.rb', line 31

def get_length_size
  return false if @data.empty?

  # High bits used for length type
  # Low bits used as first bits of length
  
  # 0xxxxxxx = 7  bit length
  # 10xxxxxx = 14 bit length
  # 110xxxxx = 21 bit length
  # 1110xxxx = 28 bit length
  # 11110000 = 32 bit length follows

  t = @data.unpack('C').first

  return  7 if t &  0b10000000 == 0
  return 14 if t &  0b01000000 == 0
  return 21 if t &  0b00100000 == 0
  return 28 if t &  0b00010000 == 0
  return 32 if t == 0b11110000

  raise ArgumentError, "Invalid length type encoding"
end

- (Object) get_sentence 



102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
 
# File 'lib/mikrotik/protocol/parser.rb', line 102

def get_sentence
  while word = get_word 
    if word.empty?
      Mikrotik.debug [:parser, :got_sentence, @sentence]
      on_sentence(@sentence)
      reset!
      return true
    else
      if word =~ PAIR
        key, value = word.scan(PAIR).flatten
        @sentence[key] = value
      else
        @sentence[word] = nil
      end
    end
  end

  return false
end

- (Object) get_word 



85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
 
# File 'lib/mikrotik/protocol/parser.rb', line 85

def get_word
  return false if @data.empty?
  length_size = bytes(get_length_size + 1)
  length      = get_length
  
  total_size  = length_size + length
  
  if length && @data.size >= total_size
    @data.slice!(0, length_size)
    word = @data.slice!(0, length)
    Mikrotik.debug [:parser, :got_word, word]
    return word
  end

  return false
end

- (Object) reset!

Discards the sentence currently being parsed



16
17
18
 
# File 'lib/mikrotik/protocol/parser.rb', line 16

def reset!
  @sentence = Mikrotik::Protocol::Sentence.new
end

- (Object) sentence {|Mikrotik::Protocol::Sentence| ... }

Fired when the parser extracts a complete API sentence

Yields:



7
 
# File 'lib/mikrotik/protocol/parser.rb', line 7

has_event :sentence