Web Features

Evennia is its own webserver and hosts a default website and browser webclient.

Web site

The Evennia website is a Django application that ties in with the MUD database. Since the website shares this database you could, for example, tell website visitors how many players are logged into the game at the moment, how long the server has been up and any other database information you may want. During development you can access the website by pointing your browser to http://localhost:8000.

You may also want to set DEBUG = True in your settings file for debugging the website. You will then see proper tracebacks in the browser rather than just error codes. Note however that this will leak memory a lot (it stores everything all the time) and is not to be used in production. It’s recommended to only use DEBUG for active web development and to turn it off otherwise.

A Django (and thus Evennia) website basically consists of three parts, a view an associated template and an urls.py file. Think of the view as the Python back-end and the template as the HTML files you are served, optionally filled with data from the back-end. The urls file is a sort of mapping that tells Django that if a specific URL is given in the browser, a particular view should be triggered. You are wise to review the Django documentation for details on how to use these components.

Evennia’s default website is located in evennia/web/website. In this folder you’ll find the simple default view as well as subfolders templates and static. Static files are things like images, CSS files and Javascript.

Customizing the Website

You customize your website from your game directory. In the folder web you’ll find folders static, templates, static_overrides and templates_overrides. The first two of those are populated automatically by Django and used to serve the website. You should not edit anything in them - the change will be lost. To customize the website you’ll need to copy the file you want to change from the web/website/template/ or web/website/static/ path to the corresponding place under one of_overrides` directories.

Example: To override or modify evennia/web/website/template/website/index.html you need to add/modify mygame/web/template_overrides/website/index.html.

The detailed description on how to customize the website is best described in tutorial form. See the Web Tutorial for more information.

Overloading Django views

The Python backend for every HTML page is called a Django view. A view can do all sorts of functions, but the main one is to update variables data that the page can display, like how your out-of-the-box website will display statistics about number of users and database objects.

To re-point a given page to a view.py of your own, you need to modify mygame/web/urls.py. An URL pattern is a regular expression that you need to enter in the address field of your web browser to get to the page in question. If you put your own URL pattern before the default ones, your own view will be used instead. The file urls.py even marks where you should put your change.

Here’s an example:

# mygame/web/urls.py

from django.conf.urls import url, include
# default patterns
from evennia.web.urls import urlpatterns

# our own view to use as a replacement
from web.myviews import myview

# custom patterns to add
patterns = [
    # overload the main page view
    url(r'^', myview, name='mycustomview'),
]

urlpatterns = patterns + urlpatterns

Django will always look for a list named urlpatterns which consists of the results of url() calls. It will use the first match it finds in this list. Above, we add a new URL redirect from the root of the website. It will now our own function myview from a new module mygame/web/myviews.py.

If our game is found on http://mygame.com, the regular expression "^" means we just entered mygame.com in the address bar. If we had wanted to add a view for http://mygame.com/awesome, the regular expression would have been ^/awesome.

Look at evennia/web/website/views.py to see the inputs and outputs you must have to define a view. Easiest may be to copy the default file to mygame/web to have something to modify and expand on.

Restart the server and reload the page in the browser - the website will now use your custom view. If there are errors, consider turning on settings.DEBUG to see the full tracebacks - in debug mode you will also log all requests in mygame/server/logs/http_requests.log.

Web client

Evennia comes with a MUD client accessible from a normal web browser. During development you can try it at http://localhost:8000/webclient. The client consists of several parts, all under evennia/web/webclient/:

  • templates/webclient/webclient.html and templates/base.html are the very simplistic django html templates describing the webclient layout. The base.html acts as a header that sets up all the basic stuff the client needs, so one only needs to modify the much cleaner webclient.html.
  • static/webclient/evennia.js is the main evennia javascript library. This handles all communication between Evennia and the client over websockets and via AJAX/COMET if the browser can’t handle websockets. It will make the Evennia object available to the javascript namespace, which offers methods for sending and receiving data to/from the server transparently. This is intended to be used also if swapping out the gui front end.
  • static/webclient/js/evennia.js is the default GUI of the webclient. This handles the input line, the send button and sends text to the right DOM elements in the html file. It makes use of the evennia.js library for all in/out and implements a “telnet-like” interface.
  • static/webclient/css/webclient.css is the CSS file for the client; it also defines things like how to display ANSI/Xterm256 colors etc.
  • The server-side webclient protocols are found in evennia/server/portal/webclient.py and webclient_ajax.py for the two types of connections. You can’t (and should not need to) modify these.

Customizing the web client

Like was the case for the website, you override the webclient from your game directory. You need to add/modify a file in the matching directory location within one of the _overrides directories.

Example: To replace/modify evennia/web/webclient/static/webclient/js/webclient_gui.js you need copy and modify the file at mygame/web/static_overrides/webclient/js/webclient_gui.js.

See the Web Tutorial for more on how to customize the webclient.

The Django ‘Admin’ Page

Django comes with a built-in admin website. This is accessible by clicking the ‘admin’ button from your game website. The admin site allows you to see, edit and create objects in your database from a graphical interface.

The behavior of default Evennia models are controlled by files admin.py in the Evennia package. New database models you choose to add yourself (such as in the Web Character View Tutorial) can/will also have admin.py files. New models are registered to the admin website by a call of admin.site.register(model class, admin class) inside an admin.py file. It is an error to attempt to register a model that has already been registered.

To overload Evennia’s admin files you don’t need to modify Evennia itself. To customize you can call admin.site.unregister(model class), then follow that with admin.site.register in one of your own admin.py files in a new app that you add.

More reading

Evennia relies on Django for its web features. For details on expanding your web experience, the Django documentation or the Django Book are the main resources to look into. In Django lingo, the Evennia is a django “project” that consists of Django “applications”. For the sake of web implementation, the relevant django “applications” in default Evennia are web/website or web/webclient.