Class: Vivarium::HttpDecoder

Inherits:
Object
  • Object
show all
Defined in:
lib/vivarium/http_decoder.rb

Overview

Decodes payloads captured from OpenSSL ‘SSL_write` into a human-readable one-liner. Auto-detects HTTP/1.x request/response lines and HTTP/2 binary frames; HPACK-decompresses HEADERS / CONTINUATION when the `http-2` gem is available, otherwise reports frame types only.

HPACK decompressor state is kept per pid. This is sufficient for the common “one HTTPS connection per process” case; with multiple concurrent TLS connections per pid the HPACK table can diverge and decoding may fail — in that case the decompressor for that pid is reset on the next decode error.

Constant Summary collapse

HTTP1_METHODS = 
%w[GET POST PUT PATCH DELETE HEAD OPTIONS TRACE CONNECT].freeze
HTTP2_PREFACE = 
"PRI * HTTP/2.0\r\n\r\nSM\r\n\r\n".b
H2_FRAME_HEADER_SIZE = 
9
H2_FLAG_END_HEADERS = 
0x04
H2_FLAG_PADDED = 
0x08
H2_FLAG_PRIORITY = 
0x20
FRAME_TYPE_NAMES = 
{
  0x0 => "DATA",
  0x1 => "HEADERS",
  0x2 => "PRIORITY",
  0x3 => "RST_STREAM",
  0x4 => "SETTINGS",
  0x5 => "PUSH_PROMISE",
  0x6 => "PING",
  0x7 => "GOAWAY",
  0x8 => "WINDOW_UPDATE",
  0x9 => "CONTINUATION"
}.freeze

Instance Method Summary collapse

Constructor Details

#initialize ⇒ HttpDecoder

Returns a new instance of HttpDecoder.



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# File 'lib/vivarium/http_decoder.rb', line 40

def initialize
  @hpack_available = load_http2_gem
  @decompressors = {}
  @continuation = {}
end

Instance Method Details

#hpack_available? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/vivarium/http_decoder.rb', line 46

def hpack_available?
  @hpack_available
end

#render(pid:, data:, data_len:) ⇒ Object 



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# File 'lib/vivarium/http_decoder.rb', line 50

def render(pid:, data:, data_len:)
  data = data.to_s.b
  data_len = data_len.to_i

  return "data_len=0" if data_len <= 0
  return "len=#{data_len} <no-capture>" if data.empty?

  if (summary = http1_summary(data))
    kind, line = summary
    return "http/1.x #{kind}: #{line}#{truncation_note(data, data_len)}"
  end

  rest = data
  preface_note = ""
  if rest.start_with?(HTTP2_PREFACE)
    preface_note = "preface "
    rest = rest.byteslice(HTTP2_PREFACE.bytesize..) || "".b
  end

  frames = parse_h2_frames(rest)
  if frames.empty?
    if !preface_note.empty?
      return "h2 preface only#{truncation_note(data, data_len)}"
    end
    return "binary len=#{data_len}#{truncation_note(data, data_len)}"
  end

  rendered = frames.map { |f| render_h2_frame(pid, f) }.join(" | ")
  "h2 #{preface_note}#{rendered}#{truncation_note(data, data_len)}"
end