Permissions¶
A permission is simply a text string stored in the handler permissions
on Objects
and Accounts
. Think of it as a specialized sort of Tag - one specifically dedicated to access checking. They are thus often tightly coupled to Locks. Permission strings are not case-sensitive, so “Builder” is the same as “builder” etc.
Permissions are used as a convenient way to structure access levels and hierarchies. It is set by the perm
command and checked by the PermissionHandler.check
method as well as by the specially the perm()
and pperm()
lock functions.
All new accounts are given a default set of permissions defined by settings.PERMISSION_ACCOUNT_DEFAULT
.
The super user¶
There are strictly speaking two types of users in Evennia, the super user and everyone else. The
superuser is the first user you create, object #1
. This is the all-powerful server-owner account.
Technically the superuser not only has access to everything, it bypasses the permission checks
entirely.
This makes the superuser impossible to lock out, but makes it unsuitable to actually play-
test the game’s locks and restrictions with (see quell
below). Usually there is no need to have
but one superuser.
Working with Permissions¶
In-game, you use the perm
command to add and remove permissions
> perm/account Tommy = Builders
> perm/account/del Tommy = Builders
Note the use of the /account
switch. It means you assign the permission to the Accounts Tommy instead of any Character that also happens to be named “Tommy”. If you don’t want to use /account
, you can also prefix the name with *
to indicate an Account is sought:
> perm *Tommy = Builders
There can be reasons for putting permissions on Objects (especially NPCS), but for granting powers to players, you should usually put the permission on the Account
- this guarantees that they are kept, regardless of which Character they are currently puppeting.
This is especially important to remember when assigning permissions from the hierarchy tree (see below), as an Account’s permissions will overrule that of its character. So to be sure to avoid confusion you should generally put hierarchy permissions on the Account, not on their Characters/puppets.
If you do want to start using the permissions on your puppet, you use quell
> quell
> unquell
This drops to the permissions on the puppeted object, and then back to your Account-permissions again. Quelling is useful if you want to try something “as” someone else. It’s also useful for superusers since this makes them susceptible to locks (so they can test things).
In code, you add/remove Permissions via the PermissionHandler
, which sits on all
typeclassed entities as the property .permissions
:
account.permissions.add("Builders")
account.permissions.add("cool_guy")
obj.permissions.add("Blacksmith")
obj.permissions.remove("Blacksmith")
The permission hierarchy¶
Selected permission strings can be organized in a permission hierarchy by editing the tuple
settings.PERMISSION_HIERARCHY
. Evennia’s default permission hierarchy is as follows
(in increasing order of power):
Guest # temporary account, only used if GUEST_ENABLED=True (lowest)
Player # can chat and send tells (default level)
Helper # can edit help files
Builder # can edit the world
Admin # can administrate accounts
Developer # like superuser but affected by locks (highest)
(Besides being case-insensitive, hierarchical permissions also understand the plural form, so you could use Developers
and Developer
interchangeably).
When checking a hierarchical permission (using one of the methods to follow), you will pass checks for your level and below. That is, if you have the “Admin” hierarchical permission, you will also pass checks asking for “Builder”, “Helper” and so on.
By contrast, if you check for a non-hierarchical permission, like “Blacksmith” you must have exactly that permission to pass.
Checking permissions¶
It’s important to note that you check for the permission of a puppeted Object (like a Character), the check will always first use the permissions of any Account
connected to that Object before checking for permissions on the Object. In the case of hierarchical permissions (Admins, Builders etc), the Account permission will always be used (this stops an Account from escalating their permission by puppeting a high-level Character). If the permission looked for is not in the hierarchy, an exact match is required, first on the Account and if not found there (or if no Account is connected), then on the Object itself.
Checking with obj.permissions.check()¶
The simplest way to check if an entity has a permission is to check its PermissionHandler, stored as .permissions
on all typeclassed entities.
if obj.permissions.check("Builder"):
# allow builder to do stuff
if obj.permissions.check("Blacksmith", "Warrior"):
# do stuff for blacksmiths OR warriors
if obj.permissions.check("Blacksmith", "Warrior", require_all=True):
# only for those that are both blacksmiths AND warriors
Using the .check
method is the way to go, it will take hierarchical
permissions into account, check accounts/sessions etc.
Warning
Don't confuse `.permissions.check()` with `.permissions.has()`. The .has()
method checks if a string is defined specifically on that PermissionHandler.
It will not consider permission-hierarchy, puppeting etc. `.has` can be useful
if you are manipulating permissions, but use `.check` for access checking.
Lock funcs¶
While the PermissionHandler
offers a simple way to check perms, Lock
strings offers a mini-language for describing how something is accessed.
The perm()
lock function is the main tool for using Permissions in locks.
Let’s say we have a red_key
object. We also have red chests that we want to
unlock with this key.
perm red_key = unlocks_red_chests
This gives the red_key
object the permission “unlocks_red_chests”. Next we
lock our red chests:
lock red chest = unlock:perm(unlocks_red_chests)
When trying to unlock the red chest with this key, the chest Typeclass could then take the key and do an access check:
# in some typeclass file where chest is defined
class TreasureChest(Object):
# ...
def open_chest(self, who, tried_key):
if not chest.access(who, tried_key, "unlock"):
who.msg("The key does not fit!")
return
else:
who.msg("The key fits! The chest opens.")
# ...
There are several variations to the default perm
lockfunc:
perm_above
- requires a hierarchical permission higher than the one provided. Example:"edit: perm_above(Player)"
pperm
- looks only for permissions onAccounts
, never at any puppeted objects (regardless of hierarchical perm or not).pperm_above
- likeperm_above
, but for Accounts only.
Some examples¶
Adding permissions and checking with locks
account.permissions.add("Builder")
account.permissions.add("cool_guy")
account.locks.add("enter:perm_above(Player) and perm(cool_guy)")
account.access(obj1, "enter") # this returns True!
An example of a puppet with a connected account:
account.permissions.add("Player")
puppet.permissions.add("Builders")
puppet.permissions.add("cool_guy")
obj2.locks.add("enter:perm_above(Accounts) and perm(cool_guy)")
obj2.access(puppet, "enter") # this returns False, since puppet permission
# is lower than Account's perm, and perm takes
# precedence.
Quelling¶
The quell
command can be used to enforce the perm()
lockfunc to ignore
permissions on the Account and instead use the permissions on the Character
only. This can be used e.g. by staff to test out things with a lower permission
level. Return to the normal operation with unquell
. Note that quelling will
use the smallest of any hierarchical permission on the Account or Character, so
one cannot escalate one’s Account permission by quelling to a high-permission
Character. Also the superuser can quell their powers this way, making them
affectable by locks.