module Roda::RodaPlugins::HmacPaths::RequestMethods

def hmac_path(opts=OPTS, &block)

block does not matches and routing continues after the call.
block matches and is yielded to, and the result of the block is returned. Otherwise, the
rest of the path considering the flags in the second segment and the given options, the
Looks at the first segment of the remaining path, and if it contains a valid HMAC for the 
def hmac_path(opts=OPTS, &block)
  orig_path = remaining_path
  mpath = matched_path
  on String do |submitted_hmac|
    rpath = remaining_path
    if submitted_hmac.bytesize == 64
      on String do |flags|
        if flags.bytesize >= 1
          if flags.include?('n') ^ !scope.hmac_path_namespace(opts).nil?
            # Namespace required and not provided, or provided and not required.
            # Bail early to avoid unnecessary HMAC calculation.
            @remaining_path = orig_path
            return
          end
          if flags.include?('m')
            rpath = "#{env['REQUEST_METHOD'].to_s.upcase}:#{rpath}"
          end
          if flags.include?('p')
            rpath = "#{rpath}?#{env["QUERY_STRING"]}"
          end
          if hmac_path_valid?(mpath, rpath, submitted_hmac, opts)
            if flags.include?('t')
              on Integer do |int|
                if int >= Time.now.to_i
                  always(&block)
                else
                  # Return from method without matching
                  @remaining_path = orig_path
                  return
                end
              end
            else
              always(&block)
            end
          end
        end
        # Return from method without matching
        @remaining_path = orig_path
        return
      end
    end
    # Return from method without matching
    @remaining_path = orig_path
    return
  end
end

def hmac_path_valid?(root, path, hmac, opts=OPTS)

Determine whether the provided hmac matches. 
def hmac_path_valid?(root, path, hmac, opts=OPTS)
  if Rack::Utils.secure_compare(scope.hmac_path_hmac(root, path, opts), hmac)
    true
  elsif old_secret = roda_class.opts[:hmac_paths_old_secret]
    opts = opts.dup
    opts[:secret] = old_secret
    Rack::Utils.secure_compare(scope.hmac_path_hmac(root, path, opts), hmac)
  else
    false
  end
end