message_ui.routing.yml

entity.message.canonical:
  path: '/message/{message}'
  defaults:
  # Calls the view controller, defined the message entity alter hook.
    _entity_view: 'message'
    _title: 'Message Content'
  requirements:
  # Calls the access controller of the entity, $operation 'view'
    _entity_access: 'message.view'

message_ui.add_page:
  path: '/message/add'
  defaults:
    _title: 'Add Message'
    _controller: '\Drupal\message_ui\Controller\MessageController::addPage'
    # appears_on: # Should we define a route for converting MENU_LOCAL_ACTION.
  requirements:
     _entity_create_access: 'message'
  options:
    _admin_route: TRUE

message_ui.add:
  path: '/message/add/{message_template}'
  defaults:
  # Calls the form.add controller, defined in the message entity alter hook.
    _controller: '\Drupal\message_ui\Controller\MessageController::add'
    _title: 'Create Message'
  requirements:
    _entity_create_access: 'message:{message_template}'
  options:
    _admin_route: TRUE
    parameters:
      message_template:
        with_config_overrides: FALSE

entity.message.edit_form:
  path: '/message/{message}/edit'
  defaults:
  # Calls the form.edit controller, defined in the message entity alter hook.
    _entity_form: message.edit
    _title: 'Edit Message'
  requirements:
    _entity_access: 'message.edit'
  options:
    _admin_route: TRUE

entity.message.delete_form:
  path: '/message/{message}/delete'
  defaults:
    # Calls the form.delete controller, defined in the message entity alter hook.
    _entity_form: message.delete
    _title: 'Delete Message'
  requirements:
    _entity_access: 'message.delete'
  options:
    _admin_route: TRUE

message_ui.message_multiple_delete_form:
  path: '/admin/config/message/message_delete_multiple'
  defaults:
    _form: '\Drupal\message_ui\Form\MessageMultipleDeleteForm'
    _title: 'Message multiple deleteForm'
  requirements:
    _permission: 'delete multiple messages'