4. Overview of your new Game Dir

Until now we have ‘run the game’ a bit and started playing with Python inside Evennia. It is time to start to look at how things look ‘outside of the game’.

Let’s do a tour of your game-dir (we assume it’s called mygame).

When looking through files, ignore files ending with .pyc and the __pycache__ folder if it exists. This is internal Python compilation files that you should never need to touch. Files __init__.py is also often empty and can be ignored (they have to do with Python package management).

You may have noticed when we were building things in-game that we would often refer to code through “python paths”, such as

create/drop button:tutorial_examples.red_button.RedButton

This is a fundamental aspect of coding Evennia - you create code and then you tell Evennia where that code is and when it should be used. Above we told it to create a red button by pulling from specific code in the contrib/ folder. The same principle is true everywhere. So it’s important to know where code is and how you point to it correctly.

  • mygame/

    • commands/ - This holds all your custom commands (user-input handlers). You both add your own and override Evennia’s defaults from here.

    • server/ - The structure of this folder should not change since Evennia expects it.

      • conf/ - All server configuration files sits here. The most important file is settings.py.

      • logs/ - Server log files are stored here. When you use evennia --log you are actually tailing the files in this directory.

    • typeclasses/ - this holds empty templates describing all database-bound entities in the game, like Characters, Scripts, Accounts etc. Adding code here allows to customize and extend the defaults.

    • web/ - This is where you override and extend the default templates, views and static files used for Evennia’s web-presence, like the website and the HTML5 webclient.

    • world/ - this is a “miscellaneous” folder holding everything related to the world you are building, such as build scripts and rules modules that don’t fit with one of the other folders.

The server/ subfolder should remain the way it is - Evennia expects this. But you can change the structure of the rest of your game dir as best fits your preferences. Maybe you don’t want a single world/ folder but prefer many folders with different aspects of your world? A new folder ‘rules’ for your RPG rules? Group your commands with your objects instead of having them separate? This is fine. If you move things around you just need to update Evennia’s default settings to point to the right places in the new structure.

4.1. commands/

The commands/ folder holds Python modules related to creating and extending the Commands of Evennia. These manifest in game like the server understanding input like look or dig.

  • command.py (Python-path: commands.command) - this contain the base classes for designing new input commands, or override the defaults.

  • default_cmdsets.py (Python path: commands.default_commands) - a cmdset (Command-Set) groups Commands together. Command-sets can be added and removed from objects on the fly, meaning a user could have a different set of commands (or versions of commands) available depending on their circumstance in the game. In order to add a new command to the game, it’s common to import the new command-class from command.py and add it to one of the default cmdsets in this module.

4.2. server/

This folder contains resource necessary for running Evennia. Contrary to the other folders, the structure of this should be kept the way it is.

  • evennia.db3 - you will only have this file if you are using the default SQLite3 database. This file contains the entire database. Just copy it to make a backup. For development you could also just make a copy once you have set up everything you need and just copy that back to ‘reset’ the state. If you delete this file you can easily recreate it by running evennia migrate.

4.2.1. server/logs/

This holds the server logs. When you do evennia --log, the evennia program is in fact tailing and concatenating the server.log and portal.log files in this directory. The logs are rotated every week. Depending on your settings, other logs, like the webserver HTTP request log can also be found here.

4.2.2. server/conf/

This contains all configuration files of the Evennia server. These are regular Python modules which means that they must be extended with valid Python. You can also add logic to them if you wanted to.

Common for the settings is that you generally will never them directly via their python-path; instead Evennia knows where they are and will read them to configure itself at startup.

  • settings.py - this is by far the most important file. It’s nearly empty by default, rather you are expected to copy&paste the changes you need from evennia/default_settings.py. The default settings file is extensively documented. Importing/accessing the values in the settings file is done in a special way, like this:

      from django.conf import settings 

    To get to the setting TELNET_PORT in the settings file you’d then do

      telnet_port = settings.TELNET_PORT

    You cannot assign to the settings file dynamically; you must change the settings.py file directly to change a setting. See Settings documentation for more details.

  • secret_settings.py - If you are making your code effort public, you may not want to share all settings online. There may be server-specific secrets or just fine-tuning for your game systems that you prefer be kept secret from the players. Put such settings in here, it will override values in settings.py and not be included in version control.

  • at_initial_setup.py - When Evennia starts up for the very first time, it does some basic tasks, like creating the superuser and Limbo room. Adding to this file allows to add more actions for it to for first-startup.

  • at_search.py - When searching for objects and either finding no match or more than one match, it will respond by giving a warning or offering the user to differentiate between the multiple matches. Modifying the code here will change this behavior to your liking.

  • at_server_startstop.py - This allows to inject code to execute every time the server starts, stops or reloads in different ways.

  • connection_screens.py - This allows for changing the connection screen you see when you first connect to your game.

  • inlinefuncs.py - Inlinefuncs are optional and limited ‘functions’ that can be embedded in any strings being sent to a player. They are written as $funcname(args) and are used to customize the output depending on the user receiving it. For example sending people the text "Let's meet at $realtime(13:00, GMT)! would show every player seeing that string the time given in their own time zone. The functions added to this module will become new inlinefuncs in the game.

  • inputfucs.py - When a command like look is received by the server, it is handled by an inputfunc that redirects it to the cmdhandler system. But there could be other inputs coming from the clients, like button-presses or the request to update a health-bar. While most common cases are already covered, this is where one adds new functions to process new types of input.

  • lockfuncs.py - Locks restrict access to things in-game. Lock funcs are used in a mini-language to defined more complex locks. For example you could have a lockfunc that checks if the user is carrying a given item, is bleeding or has a certain skill value. New functions added in this modules will become available for use in lock definitions.

  • mssp.py - Mud Server Status Protocol is a way for online MUD archives/listings (which you usually have to sign up for) to track which MUDs are currently online, how many players they have etc. While Evennia handles the dynamic information automatically, this is were you set up the meta-info about your game, such as its theme, if player-killing is allowed and so on. This is a more generic form of the Evennia Game directory.

  • portal_services_plugins.py - If you want to add new external connection protocols to Evennia, this is the place to add them.

  • server_services_plugins.py - This allows to override internal server connection protocols.

  • web_plugins.py - This allows to add plugins to the Evennia webserver as it starts.

4.2.3. typeclasses/

The Typeclasses of Evennia are Evennia-specific Python classes whose instances save themselves to the database. This allows a Character to remain in the same place and your updated strength stat to still be the same after a server reboot.

  • accounts.py (Python-path: typeclasses.accounts) - An Account represents the player connecting to the game. It holds information like email, password and other out-of-character details.

  • channels.py (Python-path: typeclasses.channels) - Channels are used to manage in-game communication between players.

  • objects.py (Python-path: typeclasses.objects) - Objects represent all things having a location within the game world.

  • characters.py (Python-path: typeclasses.characters) - The Character is a subclass of Objects, controlled by Accounts - they are the player’s avatars in the game world.

  • rooms.py (Python-path: typeclasses.rooms) - A Room is also a subclass of Object; describing discrete locations. While the traditional term is ‘room’, such a location can be anything and on any scale that fits your game, from a forest glade, an entire planet or an actual dungeon room.

  • exits.py (Python-path: typeclasses.exits) - Exits is another subclass of Object. Exits link one Room to another.

  • scripts.py (Python-path: typeclasses.scripts) - Scripts are ‘out-of-character’ objects. They have no location in-game and can serve as basis for anything that needs database persistence, such as combat, weather, or economic systems. They also have the ability to execute code repeatedly, on a timer.

4.2.4. web/

This folder contains folders for overriding the default web-presence of Evennia with your own designs. Most of these folders are empty except for a README file or a subset of other empty folders. See the Web overview for more details (we’ll also get back to the web later in this beginner tutorial).

  • media/ - this empty folder is where you can place your own images or other media files you want the web server to serve. If you are releasing your game with a lot of media (especially if you want videos) you should consider re-pointing Evennia to use some external service to serve your media instead.

  • static_overrides/ - ‘static’ files include fonts, CSS and JS. Within this folder you’ll find sub-folders for overriding the static files for the admin (this is the Django web-admin), the webclient (this is thet HTML5 webclient) and the website. Adding files to this folder will replace same-named files in the default web presence.

  • template_overrides/ - these are HTML files, for the webclient and the website. HTML files are written using Jinja templating, which means that one can override only particular parts of a default template without touching others.

  • static/ - this is a work-directory for the web system and should not be manually modified. Basically, Evennia will copy static data from static_overrides here when the server starts.

  • urls.py - this module links up the Python code to the URLs you go to in the browser.

4.2.5. world/

This folder only contains some example files. It’s meant to hold ‘the rest’ of your game implementation. Many people change and re-structure this in various ways to better fit their ideas.

  • batch_cmds.ev - This is an .ev file, which is essentially just a list of Evennia commands to execute in sequence. This one is empty and ready to expand on. The Tutorial World was built with such a batch-file.

  • prototypes.py - A prototype is a way to easily vary objects without changing their base typeclass. For example, one could use prototypes to tell that Two goblins, while both of the class ‘Goblin’ (so they follow the same code logic), should have different equipment, stats and looks.