Initial stab at AMF parsing. Handles strings, numbers, booleans, and …

…objects (hashes).
threedaymonk · Jun 28, 2008 · b8d15de · b8d15de
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diff --git a/lib/net/rtmp/amf.rb b/lib/net/rtmp/amf.rb
@@ -0,0 +1,79 @@
+require 'net/rtmp/packet'
+require 'stringio'
+
+module Net
+class RTMP
+class AMF
+
+  EndOfPacket = Class.new
+
+  DT_NUMBER       = 0x00
+  DT_BOOLEAN      = 0x01
+  DT_STRING       = 0x02
+  DT_OBJECT       = 0x03
+  DT_MOVIECLIP    = 0x04
+  DT_NULL_VALUE   = 0x05
+  DT_UNDEFINED    = 0x06
+  DT_REFERENCE    = 0x07
+  DT_ECMA_ARRAY   = 0x08
+  DT_OBJECT_END   = 0x09
+  DT_STRICT_ARRAY = 0x0a
+  DT_DATE         = 0x0b
+  DT_LONG_STRING  = 0x0c
+  DT_UNSUPPORTED  = 0x0d
+  DT_RECORD_SET   = 0x0e
+  DT_XML_OBJECT   = 0x0f
+  DT_TYPED_OBJECT = 0x10 
+
+  def initialize
+    @elements = []
+  end
+
+  def parse(data)
+    @elements = recursive_parse(StringIO.new(data))
+  end
+
+  def to_a
+    @elements
+  end
+
+private
+
+  def recursive_parse(io)
+    elements = []
+    until (e = next_element(io)) == EndOfPacket
+      elements << e
+    end
+    elements
+  end
+
+  def next_element(io)
+    data_type = io.read(1).unpack('C')[0]
+    case data_type
+    when DT_NUMBER
+      io.read(8).unpack('G')[0]
+    when DT_BOOLEAN
+      io.read(1).unpack('C')[0] != 0
+    when DT_OBJECT
+      hash = {}
+      until (key = read_length_prefixed_data(io)) == ''
+        hash[key] = next_element(io)
+      end
+      hash
+    when DT_STRING, DT_LONG_STRING
+      read_length_prefixed_data(io)
+    when DT_OBJECT_END
+      EndOfPacket
+    else
+      read_length_prefixed_data(io)
+    end 
+  end
+
+  def read_length_prefixed_data(io)
+    length = io.read(2).unpack('n')[0]
+    io.read(length)
+  end
+
+end
+end
+end
diff --git a/test/test_amf.rb b/test/test_amf.rb
@@ -0,0 +1,80 @@
+$:.unshift(File.join(File.dirname(__FILE__), '..', 'lib'))
+require 'net/rtmp/amf'
+require 'test/unit'
+require 'mocha'
+
+class AMFTest < Test::Unit::TestCase
+
+  SAMPLE = %w[
+    02 00 07 63 6f 6e 6e 65   63 74 00 3f f0 00 00 00
+    00 00 00 03 00 03 61 70   70 02 00 c5 6f 6e 64 65
+    6d 61 6e 64 3f 5f 66 63   73 5f 76 68 6f 73 74 3d
+    63 70 34 38 31 38 34 2e   65 64 67 65 66 63 73 2e
+    6e 65 74 26 61 75 74 68   3d 64 61 45 63 49 61 4b
+    61 51 64 66 61 69 63 5a   63 42 61 5f 61 4c 61 39
+    64 59 62 68 64 43 61 43   63 33 64 39 2d 62 69 7a
+    77 51 42 2d 63 43 70 2d   46 6e 72 44 43 71 42 6e
+    4e 44 6f 47 75 77 46 26   61 69 66 70 3d 76 30 30
+    31 26 73 6c 69 73 74 3d   73 65 63 75 72 65 2f 36
+    6d 75 73 69 63 2f 41 4d   49 5f 65 36 64 30 31 62
+    66 36 33 39 66 65 33 37   62 65 33 61 34 32 65 34
+    32 33 66 39 66 33 38 34   32 35 5f 62 30 30 63 37
+    33 64 32 5f 36 6d 5f 6c   61 6d 61 63 71 5f 74 68
+    75 00 08 66 6c 61 73 68   56 65 72 02 00 0d 4c 4e
+    58 20 39 2c 30 2c 31 32   34 2c 30 00 06 73 77 66
+    55 72 6c 02 00 31 68 74   74 70 3a 2f 2f 77 77 77
+    2e 62 62 63 2e 63 6f 2e   75 6b 2f 65 6d 70 2f 70
+    6c 61 79 65 72 2e 73 77   66 3f 72 65 76 69 73 69
+    6f 6e 3d 33 37 30 34 00   05 74 63 55 72 6c 02 00
+    df 72 74 6d 70 3a 2f 2f   38 34 2e 35 33 2e 31 37
+    37 2e 31 34 30 3a 31 39   33 35 2f 6f 6e 64 65 6d
+    61 6e 64 3f 5f 66 63 73   5f 76 68 6f 73 74 3d 63
+    70 34 38 31 38 34 2e 65   64 67 65 66 63 73 2e 6e
+    65 74 26 61 75 74 68 3d   64 61 45 63 49 61 4b 61
+    51 64 66 61 69 63 5a 63   42 61 5f 61 4c 61 39 64
+    59 62 68 64 43 61 43 63   33 64 39 2d 62 69 7a 77
+    51 42 2d 63 43 70 2d 46   6e 72 44 43 71 42 6e 4e
+    44 6f 47 75 77 46 26 61   69 66 70 3d 76 30 30 31
+    26 73 6c 69 73 74 3d 73   65 63 75 72 65 2f 36 6d
+    75 73 69 63 2f 41 4d 49   5f 65 36 64 30 31 62 66
+    36 33 39 66 65 33 37 62   65 33 61 34 32 65 34 32
+    33 66 39 66 33 38 34 32   35 5f 62 30 30 63 37 33
+    64 32 5f 36 6d 5f 6c 61   6d 61 63 71 5f 74 68 75
+    00 04 66 70 61 64 01 00   00 0c 63 61 70 61 62 69
+    6c 69 74 69 65 73 00 40   2e 00 00 00 00 00 00 00
+    0b 61 75 64 69 6f 43 6f   64 65 63 73 00 40 99 9c
+    00 00 00 00 00 00 0b 76   69 64 65 6f 43 6f 64 65
+    63 73 00 40 6f 80 00 00   00 00 00 00 0d 76 69 64
+    65 6f 46 75 6e 63 74 69   6f 6e 00 3f f0 00 00 00
+    00 00 00 00 07 70 61 67   65 55 72 6c 02 00 31 68
+    74 74 70 3a 2f 2f 77 77   77 2e 62 62 63 2e 63 6f
+    2e 75 6b 2f 69 70 6c 61   79 65 72 62 65 74 61 2f
+    65 70 69 73 6f 64 65 2f   62 30 30 63 37 33 66 63
+    00 00 09
+  ].map{ |b| b.to_i(16) }.pack('C*')
+
+  def test_should_extract_elements_from_sample
+    amf = Net::RTMP::AMF.new
+    amf.parse(SAMPLE)
+    expected = [
+      "connect",
+      1.0,
+      {
+        "capabilities" => 15.0,
+        "videoFunction" => 1.0,
+        "audioCodecs" => 1639.0,
+        "app" =>
+          "ondemand?_fcs_vhost=cp48184.edgefcs.net&auth=daEcIaKaQdfaicZcBa_aLa9dYbhdCaCc3d9-bizwQB-cCp-FnrDCqBnNDoGuwF&aifp=v001&slist=secure/6music/AMI_e6d01bf639fe37be3a42e423f9f38425_b00c73d2_6m_lamacq_thu",
+        "videoCodecs" => 252.0,
+        "swfUrl" => "http://www.bbc.co.uk/emp/player.swf?revision=3704",
+        "pageUrl" => "http://www.bbc.co.uk/iplayerbeta/episode/b00c73fc",
+        "tcUrl" =>
+          "rtmp://84.53.177.140:1935/ondemand?_fcs_vhost=cp48184.edgefcs.net&auth=daEcIaKaQdfaicZcBa_aLa9dYbhdCaCc3d9-bizwQB-cCp-FnrDCqBnNDoGuwF&aifp=v001&slist=secure/6music/AMI_e6d01bf639fe37be3a42e423f9f38425_b00c73d2_6m_lamacq_thu",
+        "fpad" => false,
+        "flashVer" => "LNX 9,0,124,0"
+      }
+    ]
+    assert_equal expected, amf.to_a
+  end
+
+end