Class: Tep::WebSocket::Handshake

Inherits:
Object
  • Object
show all
Defined in:
lib/tep/websocket/handshake.rb

Defined Under Namespace

Classes: Result

Class Method Summary collapse

Class Method Details

.build_response(accept_key, protocol) ⇒ Object

Build the 101 Switching Protocols response. protocol empty

omit Sec-WebSocket-Protocol entirely (spec-correct per

RFC 6455 ยง4.2.2; better than echoing a protocol the server doesn't actually implement).



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# File 'lib/tep/websocket/handshake.rb', line 77

def self.build_response(accept_key, protocol)
  out = "HTTP/1.1 101 Switching Protocols\r\n" +
        "Upgrade: websocket\r\n" +
        "Connection: Upgrade\r\n" +
        "Sec-WebSocket-Accept: " + accept_key + "\r\n"
  if protocol.length > 0
    out = out + "Sec-WebSocket-Protocol: " + protocol + "\r\n"
  end
  out + "\r\n"
end

.check(req) ⇒ Object 



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# File 'lib/tep/websocket/handshake.rb', line 18

def self.check(req)
  out = Tep::WebSocket::Handshake::Result.new

  # Verb must be GET.
  if req.verb != "GET"
    out.valid = false
    out.reason = "bad verb"
    return out
  end

  # Upgrade + Connection headers (downcased per Tep::Request).
  # A missing header reads as nil; treat it as absent ("").
  upgrade = req.headers["upgrade"]
  upgrade = "" if upgrade.nil?
  if Handshake.icontains(upgrade, "websocket") == false
    out.valid = false
    out.reason = "missing/invalid Upgrade"
    return out
  end
  conn = req.headers["connection"]
  conn = "" if conn.nil?
  if Handshake.icontains(conn, "upgrade") == false
    out.valid = false
    out.reason = "missing/invalid Connection"
    return out
  end

  # Sec-WebSocket-Version must be 13.
  ver = req.headers["sec-websocket-version"]
  if ver != "13"
    out.valid = false
    out.reason = "bad/missing Sec-WebSocket-Version"
    return out
  end

  # Sec-WebSocket-Key: 24-char base64 (16-byte nonce).
  key = req.headers["sec-websocket-key"]
  key = "" if key.nil?
  if key.length == 0
    out.valid = false
    out.reason = "missing Sec-WebSocket-Key"
    return out
  end

  out.valid = true
  out.accept_key = Crypto.sp_crypto_websocket_accept(key)

  # Parse Sec-WebSocket-Protocol (comma-separated). Handler
  # gets the offered list; can opt-in via Driver.accept_protocol.
  proto_blob = req.headers["sec-websocket-protocol"]
  proto_blob = "" if proto_blob.nil?
  out.protocols = Handshake.split_csv(proto_blob)
  out
end

.downcase(s) ⇒ Object 



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# File 'lib/tep/websocket/handshake.rb', line 101

def self.downcase(s)
  out = ""
  i = 0
  while i < s.length
    c = s[i]
    if c >= "A" && c <= "Z"
      out = out + (c.ord + 32).chr
    else
      out = out + c
    end
    i += 1
  end
  out
end

.icontains(hay, needle) ⇒ Object

Case-insensitive substring contains. Hand-rolled because Tep::Request normalises header names to lowercase but leaves values as-is, and clients sometimes send Connection: keep-alive, Upgrade capitalised.



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# File 'lib/tep/websocket/handshake.rb', line 92

def self.icontains(hay, needle)
  if hay.length == 0 || needle.length == 0
    return false
  end
  hl = Handshake.downcase(hay)
  nl = Handshake.downcase(needle)
  Tep.str_find(hl, nl, 0) >= 0
end

.split_csv(s) ⇒ Object

Parse comma-separated header value into an Array. Trims whitespace around each entry.



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# File 'lib/tep/websocket/handshake.rb', line 118

def self.split_csv(s)
  out = [""]
  out.delete_at(0)
  if s.length == 0
    return out
  end
  pos = 0
  while pos < s.length
    comma = Tep.str_find(s, ",", pos)
    if comma < 0
      out.push(Handshake.trim(s[pos, s.length - pos]))
      return out
    end
    out.push(Handshake.trim(s[pos, comma - pos]))
    pos = comma + 1
  end
  out
end

.trim(s) ⇒ Object 



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# File 'lib/tep/websocket/handshake.rb', line 137

def self.trim(s)
  i = 0
  while i < s.length && (s[i] == " " || s[i] == "\t")
    i += 1
  end
  j = s.length - 1
  while j >= i && (s[j] == " " || s[j] == "\t")
    j -= 1
  end
  if j < i
    return ""
  end
  s[i, j - i + 1]
end