Nekonote Framework provides routing for Error Pages.

Error Routes

There are the following four type’s Error Routes.

Directives For Error Routes

Each route can be set the directives below. Almost directives are the same as route.yml.

You may also set custom fields in route_error.yml.

Configuring Error Routes

You can configure or turning off Error Routes on route_error.yml.

The following is the default.

preference/environment_name/route_error.yml

# This route is used when any route does not match a URL.
missing_route:
    handler: ErrorHandler
    execute: missing_route
    template: error
    layout: error

# This route is used when a HTTP method in request does not much the value set in "method" directive in route.yml.
wrong_http_method:
    handler: ErrorHandler
    execute: wrong_http_method
    template: error
    layout: error

# This route is used when a fatal error raised in your program.
# The exception object will be set to the property named @error.
fatal:
    handler: ErrorHandler
    execute: fatal
    template: error
    layout: error

# This route is used when a request file does not exist under the "public" directory.
not_found:
    handler: ErrorHandler
    execute: not_found
    template: error
    layout: error

Your application structure will contain ErrorHandler class in the handler/ directory to control the above routes.

handler/error.rb

class ErrorHandler < BaseHandler
    def missing_route
        @subject = 'Invalid URL'
        @msg     = 'The URL does not match any route'
        @detail  = %('#{Nekonote::Env.get :REQUEST_URI}' does not match any route.)
    end

    def wrong_http_method
        @subject = 'Unacceptable HTTP method'
        @msg     = 'You have accessed with the unacceptable HTTP method.'
    end

    def fatal
        @subject = 'Server Error'
        @msg     = 'You can not access this page temporary.'
    end

    def not_found
        @subject = 'No such resource'
        @msg     = %('#{Nekonote::Env.get :REQUEST_URI}' was not found on the server.)
    end

    # It will be called at last
    def __post
        # assign values to templates
        list = {}
        list['subject'] = @subject if defined?(@subject)
        list['msg']     = @msg     if defined?(@msg)
        list['detail']  = @detail  if defined?(@detail)
        __assign list

        # change the response code to not 500 but 200
        __set_code 200
    end
end

ShowExceptions And ‘fatal’ Route

While ShowExceptions is enabled, the request will not be forwarded to fatal route. ShowExceptions shows exception details on your web blowser instead. More information for exception handling is 15. Exception Handling.

Please try not to be raised any exception in the Handler class for fatal route.

Turning Off Error Routes

It’s possible to comment out the directives then error routes does not be used.

preference/your_environment/route_error.yml

#fatal:
#    handler: ErrorHandler
#    execute: fatal
#    layout: error

While not_found route has not been set, the response will be output Not Found: /path/to/request with HTTP response code 404.