Introduction

The Common Admin Mod Interface (CAMI) aims to solve two problems: admin mod intercompatibility and the inability of addons to hook into the privilege systems that many admin mods have. The two problems are detailed in the next paragraphs.

The biggest source of the admin mod incompatibility problem is usergroups. One admin mod creates a usergroup that another admin mod does not know of. Two admin mods thinking a player have different usergroups can cause quite a few bugs and confusion.

The second problem pertains third party addons. Most of them offer features that only admins or superadmins are allowed to use. Server owners might however want to customise these privileges. For example, they might want their user based moderator to be allowed to spawn a PlayX screen entity. Many admin mods have an advanced privilege system, it would be a shame if all third party mods are limited to just user/admin/superadmin.

The solution is inspired by the Common Prop Protection Interface (CPPI) by Ulysses. This document describes a common interface that every admin mod implements and uses so that information can be exchanged in a universal format.

Goals

CAMI has two goals:

• Unify interfaces between existing admin mods to allow them to coexist.
• Provide an optional interface to third party addons to create and query privileges. One that works even if no admin mod is installed.

The following two sections describe what CAMI will do with usergroups and privileges to meet these goals.

Usergroups

Usergroups are an existing concept in the Source engine. There are three default usergroups: user, admin and superadmin.
Every player has exactly one usergroup. Custom usergroups must inherit either another custom group or a default usergroup. By default, admin inherits from user and superadmin inherits from admin. Mathematically, inheritance is transitive, so superadmin also inherits from user.

For convenience, inheritance is not verified, so you need not worry about the order in which usergroups are registered. Admin mods might not have a concept of inheritance in usergroups. In that case, all usergroups are to be registered as inheriting user. That should give the highest compatibility with other admin mods.

Privileges

A privilege is a witness of permission to perform one or more actions. Privileges can be registered by third party mods to the currently installed admin mod(s). These third party mods can then query the admin mod(s) to see whether a player has the registered privilege. Note that the privilege part of CAMI is optional for admin mods. Fortunately, this is transparent for the third party mod: when no admin mod is installed that implements CAMI privileges, CAMI itself will have a default fallback based on whether the player is a user, admin or superadmin. This means CAMI is useful for third party addons even when no admin mod is installed.

API

All functions, hooks and data structures are shared, which thus exist in both the client and server realm.

Data structures

CAMI_USERGROUP

• Name :: string
• Inherits :: string

CAMI_PRIVILEGE

• Name :: string
• MinAccess :: string
• (optional) Description :: string
• (optional) HasAccess :: function(privilege :: CAMI_PRIVILEGE, actor :: Player, target :: Player) :: bool, string

Functions

This section lists the functions that CAMI provides. It should be used as a quick reference. Detailed descriptions of the functions can be found in the sh_cami.lua source file.

The ‘::’ indicates the types of the parameters and the return values of the functions. Parameters in square brackets are optional.

CAMI.UsergroupInherits(usergroupName1 :: string, usergroupName2 :: string) :: bool

CAMI.InheritanceRoot(usergroupName) :: string

CAMI.RegisterUsergroup(usergroup :: CAMI_USERGROUP, source :: any) :: CAMI_USERGROUP

CAMI.UnregisterUsergroup(name :: string, source :: any) :: bool

CAMI.GetUsergroup(usergroupName :: string) :: CAMI_USERGROUP

CAMI.RegisterPrivilege(privilege :: CAMI_PRIVILEGE) :: CAMI_PRIVILEGE

CAMI.UnregisterPrivilege(name :: string) :: bool

CAMI.GetPrivilege(name :: string) :: CAMI_PRIVILEGE

CAMI.PlayerHasAccess(actor :: Player, privilege :: string, callback :: function(bool,
string)[, target :: Player, extraInfo :: table]) :: nil

CAMI.GetPlayersWithAccess(privilege :: string, callback :: function(table)[, target :: Player, extraInfo :: Table]) :: nil

CAMI.SteamIDHasAccess(actor :: SteamID, privilege :: string, callback :: function(bool, string)[, target :: SteamID, extraInfo :: table]) :: nil

CAMI.GetUsergroups() :: [CAMI_USERGROUP]

CAMI.GetPrivileges() :: [CAMI_PRIVILEGE]

CAMI.SignalUserGroupChanged(ply :: Player, old :: string, new :: string, source :: any)

CAMI.SignalSteamIDUserGroupChanged(steamId :: string , old :: string, new :: string, source :: any)

Hooks

This section provides a list of hooks that CAMI calls. The types in the parentheses indicate the types of values they give the functions in the hook. When a hook is given a type, you are requested to return a value within the hook. E.g. in CAMI.PlayerHasAccess and CAMI.SteamIDHasAccess, true is to be returned when the admin mod decides whether a player has the privilege. Not returning a value will defer the decision to another admin mod or eventually CAMI itself.

CAMI.OnUsergroupRegistered(CAMI_USERGROUP)

CAMI.OnUsergroupUnregistered(CAMI_USERGROUP)

CAMI.OnPrivilegeRegistered(CAMI_PRIVILEGE)

CAMI.OnPrivilegeUnregistered(CAMI_PRIVILEGE)

CAMI.PlayerHasAccess(actor :: Player, privilege :: string, callback :: function(bool, string), target :: Player, extraInfo :: table) :: bool/nil

CAMI.SteamIDHasAccess(actor :: SteamID, privilege :: string, callback :: function(bool, string), target :: Player, extraInfo :: table) :: bool/nil

CAMI.PlayerUsergroupChanged(ply :: Player, from :: string, to :: string, source :: any)

CAMI.SteamIDUsergroupChanged(steamId :: string, from :: string, to :: string, source :: any)

What to implement

Both admin mods and third party addons are to ship the sh_cami.lua source file, shared.
Alongside with that, the following things should be implemented:

Admin mods

Please perform the following steps for both the server and the client. Clients need to be in sync with the server. Bugs in CAMI supporting addons are known to occur specifically when clients don’t know they have the right CAMI privileges to perform certain actions.

• Register custom usergroups with CAMI.RegisterUsergroup (not user/admin/superadmin)
• Register the removal of custom usergroups with CAMI.UnregisterUsergroup.
• Listen to other admin mods creating usergroups with the CAMI.OnUsergroupRegistered and CAMI.OnUsergroupUnregistered hooks
  • Your admin mod might load after others. When loading, check if new usergroups were created earlier with the CAMI.GetUsergroups() function.
• Call CAMI.SignalUserGroupChanged when a player’s usergroup is changed through your admin mod. Note: this will cause all admin mods to store the new usergroup of the player. As such it should not be called e.g. when simply receiving a player’s usergroup from a database on InitialSpawn. Call it when it is actually changed.
• Hook to CAMI.PlayerUsergroupChanged so your admin mod does not go out of sync with changes made in other admin mods. Note that this hook is called when CAMI.SignalUserGroupChanged is called. Keep that in mind when calling that function yourself. You can prevent things from being saved twice using the source parameter of the CAMI.SignalUserGroupChanged function.
• (optional, strongly recommended) Hook to CAMI.OnPrivilegeRegistered, this way you can let your admin mod administrate the permissions added by third party mods.
  • Your admin mod might load after others. When loading, check if new privileges were created earlier with the CAMI.GetPrivileges() function.
• (optional) Hook to CAMI.OnPrivilegeUnregistered. Some third party mods might want to remove privileges once they have become redundant.
• (optional, strongly recommended) Hook to CAMI.PlayerHasAccess. This hook allows third party addons to check whether a certain player has a privilege that they have registered. you can probably use existing logic here. Make sure to return true when your admin mod makes a decision.
• (optional) Hook to CAMI.SteamIDHasAccess if the admin mod supports offline access queries. Make sure to return true when your admin mod makes a decision.
• DO NOT register the admin mod’s privileges (registering privileges is for third party mods, not for sharing privileges between admin mods)

Third party addons

• Register custom privileges with CAMI.RegisterPrivilege.
• (optional) Unregister custom privilege with CAMI.UnregisterPrivilege when one of your privileges has become redundant.
• Call CAMI.PlayerHasAccess to see whether a player has a privilege.