Class: AgoraDynamicKey::Sign

Inherits:
Object
  • Object
show all
Defined in:
lib/dynamic_key/sign.rb

Defined Under Namespace

Classes: InvalidToken

Constant Summary collapse

MAX_SIZE = 
1024
SHA256 = 
OpenSSL::Digest.new("sha256")

Class Method Summary collapse

Class Method Details

.decode(string) ⇒ Object 



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# File 'lib/dynamic_key/sign.rb', line 46

def decode string
  docode!
rescue
  false
end

.decode!(string) ⇒ Object

Raises:



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# File 'lib/dynamic_key/sign.rb', line 52

def decode! string
  version = string[0..2]
  raise InvalidToken, "can't match version" unless version == VERSION
  appId = string[3..3+31]
  content = string[3+32..-1]
  content_binary = Base64.strict_decode64(content)
  uint16_sign_size = content_binary.unpack("v")[0]
  sign = content_binary[2, uint16_sign_size].unpack "H*"
  offset = uint16_sign_size + 2
  uint32_channel_name, uint32_uid = content_binary[offset..offset+1].unpack("VV")
  offset = offset + 8
  uint16_message_size = content_binary[offset..offset+1].unpack("v")[0]
  offset = offset + 2
  message = content_binary[offset..offset+uint16_message_size]
  salt, expired_ts = message[0..7].unpack("V*")
  privileges_size = message[8..9].unpack("v")[0]
  message[10..-1].unpack("vV"*privileges_size)
  true
end

.encode(option) ⇒ Object 



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# File 'lib/dynamic_key/sign.rb', line 15

def encode option
  encode! option
rescue
  false 
end

.encode!(option) ⇒ Object 



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# File 'lib/dynamic_key/sign.rb', line 21

def encode! option
  # pack message
  message = [option.salt, option.expired_ts].pack "VV" # pack into uint16 with little endian
  message << parse_map_uint32(option.privileges)

  # generate signature
  to_sign = "#{option.app_id}#{option.channel_name}#{option.uid}#{message}"

  sign = OpenSSL::HMAC.new(option.app_certificate, SHA256).update(to_sign).digest

  crc32_channel_name = Zlib::crc32(option.channel_name) & 0xffffffff
  crc32_uid = Zlib::crc32("#{option.uid}") & 0xffffffff

  uint32_channel_name = [crc32_channel_name].pack "V"
  uint32_uid = [crc32_uid].pack "V"

  uint16_sign_size = [sign.size].pack "v"

  uint16_message_size = [message.size].pack "v"
  # generate content
  content = "#{uint16_sign_size}#{sign}#{uint32_channel_name}#{uint32_uid}#{uint16_message_size}#{message}"
  # final content
  "#{AccessToken::VERSION}#{option.app_id}#{Base64.strict_encode64(content)}"
end