self.sign

in s3_file/libraries/s3_file.rb [17:50]

• 26 lines of code
• 4 McCabe index (conditional complexity)

    def self.sign(request, params, region, aws_access_key_id, aws_secret_access_key, token = nil)
      url = URI.parse(params[:url])
      content = request.body || ""

      algorithm = "AWS4-HMAC-SHA256"
      service = "s3"
      now = Time.now.utc
      time = now.strftime("%Y%m%dT%H%M%SZ")
      date = now.strftime("%Y%m%d")

      body_digest = Digest::SHA256.hexdigest(content)

      request["date"] = now
      request["host"] = url.host
      request["x-amz-date"] = time
      request["x-amz-security-token"] = token if token
      request["x-amz-content-sha256"] = body_digest

      canonical_query_string = url.query || ""
      canonical_headers = request.each_header.sort.map { |k, v| "#{k.downcase}:#{v.gsub(/\s+/, ' ').strip}" }.join("\n") + "\n" 
      signed_headers = request.each_name.map(&:downcase).sort.join(";")

      canonical_request = [request.method, url.path, canonical_query_string, canonical_headers, signed_headers, body_digest].join("\n")
      scope = format("%s/%s/%s/%s", date, region, service, "aws4_request")
      credential = [aws_access_key_id, scope].join("/")

      string_to_sign = "#{algorithm}\n#{time}\n#{scope}\n#{Digest::SHA256.hexdigest(canonical_request)}"
      signed_hex = sigv4(string_to_sign, aws_secret_access_key, region, date, service)
      auth_string = "#{algorithm} Credential=#{credential}, SignedHeaders=#{signed_headers}, Signature=#{signed_hex}"

      request["Authorization"] = auth_string
      request
    end