server: allow the permission level a client displays for itself to be set

server/player/conf.go

@@ -27,6 +27,9 @@ type Config struct {
 	Locale   language.Tag
 	GameMode world.GameMode
 
+	// PermissionLevel is the permission level the client displays for itself.
+	PermissionLevel session.PermissionLevel
+
 	Position               mgl64.Vec3
 	Rotation               cube.Rotation
 	Velocity               mgl64.Vec3
@@ -72,6 +75,7 @@ func (cfg Config) Apply(data *world.EntityData) {
 		mc:                  &entity.MovementComputer{Gravity: 0.08, Drag: 0.02, DragBeforeGravity: true},
 		heldSlot:            &slot,
 		gameMode:            conf.GameMode,
+		permission:          conf.PermissionLevel,
 		skin:                conf.Skin,
 		enchantSeed:         conf.EnchantmentSeed,
 		s:                   conf.Session,

server/player/player.go

@@ -48,10 +48,11 @@ type playerData struct {
 	absorptionHealth  float64
 	scale             float64
 
-	gameMode world.GameMode
-	skin     skin.Skin
-	s        *session.Session
-	h        Handler
+	gameMode   world.GameMode
+	permission session.PermissionLevel
+	skin       skin.Skin
+	s          *session.Session
+	h          Handler
 
 	inv, offHand, enderChest, ui *inventory.Inventory
 	armour                       *inventory.Armour
@@ -1546,6 +1547,25 @@ func (p *Player) GameMode() world.GameMode {
 	return p.gameMode
 }
 
+// SetPermissionLevel changes the permission level the Player's client displays
+// for itself. It unlocks vanilla functionality that the client restricts to a
+// permission level, such as the command button in the chat window, but does not
+// authorise the Player to do anything by itself: cmd.Allower decides which
+// commands a Player may run.
+func (p *Player) SetPermissionLevel(level session.PermissionLevel) {
+	if p.permission == level {
+		return
+	}
+	p.permission = level
+	p.session().SendAbilities(p)
+}
+
+// PermissionLevel returns the permission level the Player's client displays for
+// itself, as set by SetPermissionLevel.
+func (p *Player) PermissionLevel() session.PermissionLevel {
+	return p.permission
+}
+
 // HasCooldown returns true if the item passed has an active cooldown, meaning it currently cannot be used again. If the
 // world.Item passed is nil, HasCooldown always returns false.
 func (p *Player) HasCooldown(item world.Item) bool {

server/session/controllable.go

@@ -51,6 +51,7 @@ type Controllable interface {
 	Chat(msg ...any)
 	ExecuteCommand(commandLine string)
 	GameMode() world.GameMode
+	PermissionLevel() PermissionLevel
 	SetGameMode(mode world.GameMode)
 	Effects() []effect.Effect
 

server/session/permission.go

@@ -0,0 +1,30 @@
+package session
+
+import (
+	"github.com/sandertv/gophertunnel/minecraft/protocol"
+	"github.com/sandertv/gophertunnel/minecraft/protocol/packet"
+)
+
+// PermissionLevel is the permission level a client displays for itself. It only
+// decides what the client shows and allows locally, such as the command button
+// in the chat window: the server does not use it to authorise anything. Whether
+// a Controllable may run a command is decided by cmd.Allower alone.
+type PermissionLevel byte
+
+const (
+	// PermissionLevelMember is the level of an ordinary client. It is the level
+	// a Controllable has unless another one is set.
+	PermissionLevelMember PermissionLevel = iota
+	// PermissionLevelOperator is the level of a client that vanilla considers
+	// an operator.
+	PermissionLevelOperator
+)
+
+// abilityPermissions returns the permission level and command permission level
+// sent to a client for the PermissionLevel.
+func (l PermissionLevel) abilityPermissions() (byte, byte) {
+	if l == PermissionLevelOperator {
+		return packet.PermissionLevelOperator, protocol.CommandPermissionLevelGameDirectors
+	}
+	return packet.PermissionLevelMember, protocol.CommandPermissionLevelAny
+}

server/session/player.go

@@ -545,10 +545,11 @@ func (s *Session) SendAbilities(c Controllable) {
 	if mode.AllowsInteraction() {
 		abilities |= protocol.AbilityDoorsAndSwitches | protocol.AbilityOpenContainers | protocol.AbilityAttackPlayers | protocol.AbilityAttackMobs
 	}
+	permission, commandPermission := c.PermissionLevel().abilityPermissions()
 	s.writePacket(&packet.UpdateAbilities{AbilityData: protocol.AbilityData{
 		EntityUniqueID:     selfEntityRuntimeID,
-		PlayerPermissions:  packet.PermissionLevelMember,
-		CommandPermissions: protocol.CommandPermissionLevelAny,
+		PlayerPermissions:  permission,
+		CommandPermissions: commandPermission,
 		Layers: []protocol.AbilityLayer{
 			{
 				Type:             protocol.AbilityLayerTypeBase,