Handling Web Requests

  • [code]
  • [webportal]
  • [dispatcher]
  • [plugins]

When the Web Portal sends a JSON-based request to the game engine API port, several things happen:

  1. The JSON text is converted into a Web Request object.
  2. The request object is added to the Dispatcher’s dispatch queue.
  3. When it gets to that item in the queue, the Dispatcher will ask each plugin if it’s interested in that request.
  4. If a plugin returns a request handler object, the Dispatcher will call handle in the handler and then stop asking other plugins if they want the command.
  5. If no plugins handle the command, the Dispatcher will log an error.

Handling Web Requests

If a plugin wants to handle a web request, it must implement the get_web_request_handler method in its plugin module. This method is given a request object and and can return either nil (if the plugin doesn’t want the request) or a request handler class (if it does).

def self.get_web_request_handler(request)
   case request.cmd
   when "events"
     return EventsRequestHandler
   return nil

Web Request Class

The WebRequest class embodies a request from the Web Portal. It provides a number of useful methods, including a way to look up the enactor from the authorization information and to get the requested command and arguments out of the request.


Request Handler Classes

The plugin dispatchd returns a Request Handler. Like a Command Handler, it implements a handle method to gather the desired data and return it to the Web Portal.

For example:

class EventsRequestHandler
  def handle(request)
    events = Event.all.map { |e| {
      id: e.id,
      title: e.title,
      events: events,
      calendar_url: "#{AresMUSH::Game.web_portal_url}/events/ical"

Verifying Login

Like anything on the web, people spoofing the Web Portal with manual commands is a concern. If a request is going to act on the database, always make sure that it’s coming from a properly-logged-in character by calling check_login:

    error = WebHelpers.check_login(request)
    return error if error

If a request behaves differently for logged-in characters versus non, you can pass true to check_login to allow anonymous connections. Someone who isn’t logged in at all will be okay, but a spoofer pretending to be someone else will not.

For example: The forum allows anonymous access to certain categories but not others. So the call to check_login is followed immediately by a call to verify that the enactor has permissions for the requested category. An anonymous connection could read the Announcements board but not the Admin one.

    error = WebHelpers.check_login(request, true)
    return error if error
    if (!Forum.can_read_category?(request.enactor, category))
      return { error: t('forum.cannot_access_category') }