padrino/padrino-framework · error

Server handler (#{Handlers.join(', ')}) not found.

Error message

Server handler (#{Handlers.join(', ')}) not found.

What it means

Error "Server handler (#{Handlers.join(', ')}) not found." thrown in padrino/padrino-framework.

Source

Thrown at padrino-core/lib/padrino-core/server.rb:80

    # The application the server will run.
    attr_reader :app
    alias wrapped_app app

    attr_reader :options

    # Detects the supported handler to use.
    #
    # @example
    #   detect_rack_handler => <ThinHandler>
    #
    def self.detect_rack_handler
      Handlers.each do |handler|
        return handler if Rackup::Handler.get(handler.to_s.downcase)
      rescue LoadError, NameError
        # Ignored
      end
      raise "Server handler (#{Handlers.join(', ')}) not found."
    end

    # Prepares a directory for pid file.
    #
    def self.prepare_pid(pid)
      pid ||= 'tmp/pids/server.pid'
      FileUtils.mkdir_p(File.dirname(pid))
      File.expand_path(pid)
    end

    # Parses an array of server options.
    #
    def self.parse_server_options(options)
      parsed_server_options = Array(options).flat_map { |option| option.split('=', 2) }
      Utils.symbolize_keys(Hash[*parsed_server_options])
    end

    # Detects Host and Port for Rack server.

View on GitHub (pinned to 167044f3d5)

When it happens

Trigger: Thrown at padrino-core/lib/padrino-core/server.rb:80 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of padrino/padrino-framework@167044f3d5 (2026-08-23). Data as JSON: /api/errors/61b56425f994580c. Report an issue: GitHub.