class AWS::DynamoDB::Request

# File lib/aws/dynamo_db/request.rb, line 22
def initialize(*args)
  super
  headers["content-type"] = "application/json; amzn-1.0"
end

# File lib/aws/dynamo_db/request.rb, line 29
def add_authorization!(signer)

  self.access_key_id = signer.access_key_id

  headers["x-amz-date"] ||= (headers["date"] ||= Time.now.rfc822)
  headers["host"] ||= host

  raise ArgumentError, "a security token is required" unless
    signer.session_token

  headers["x-amz-security-token"] = signer.session_token

  # compute the authorization
  request_hash = OpenSSL::Digest::SHA256.digest(string_to_sign)
  signature = signer.sign(request_hash)
  headers["x-amzn-authorization"] =
    "AWS3 "+
    "AWSAccessKeyId=#{signer.access_key_id},"+
    "Algorithm=HmacSHA256,"+
    "SignedHeaders=#{headers_to_sign.join(';')},"+
    "Signature=#{signature}"
end

# File lib/aws/dynamo_db/request.rb, line 60
def canonical_headers
  headers_to_sign.map do |name|
    value = headers[name]
    "#{name.downcase.strip}:#{value.strip}\n"
  end.sort.join
end

# File lib/aws/dynamo_db/request.rb, line 52
def headers_to_sign
  headers.keys.select do |header|
    header == "content-encoding" ||
      header == "host" ||
      header =~ %r^x-amz/
  end
end

# File lib/aws/dynamo_db/request.rb, line 67
def string_to_sign
  [http_method,
   "/",
   "",
   canonical_headers,
   body].join("\n")
end