3 GitHub Repo: https://github.com/minetest/minetest_game
8 The Minetest Game subgame offers multiple new possibilities in addition to the Minetest engine's built-in API,
9 allowing you to add new plants to farming mod, buckets for new liquids, new stairs and custom panes.
10 For information on the Minetest API, visit https://github.com/minetest/minetest/blob/master/doc/lua_api.txt
13 * [XYZ] refers to a section the Minetest API
14 * [#ABC] refers to a section in this document
15 * [pos] refers to a position table `{x = -5, y = 0, z = 200}`
20 The bucket API allows registering new types of buckets for non-default liquids.
22 bucket.register_liquid(
23 "default:lava_source", -- name of the source node
24 "default:lava_flowing", -- name of the flowing node
25 "bucket:bucket_lava", -- name of the new bucket item (or nil if liquid is not takeable)
26 "bucket_lava.png", -- texture of the new bucket item (ignored if itemname == nil)
27 "Lava Bucket", -- text description of the bucket item
28 {lava_bucket = 1}, -- groups of the bucket item, OPTIONAL
29 false -- force-renew, OPTIONAL. Force the liquid source to renew if it has
30 -- a source neighbour, even if defined as 'liquid_renewable = false'.
31 -- Needed to avoid creating holes in sloping rivers.
34 The filled bucket item is returned to the player that uses an empty bucket pointing to the given liquid source.
35 When punching with an empty bucket pointing to an entity or a non-liquid node, the on_punch of the entity or node will be triggered.
41 "beds:bed", -- Bed name
42 def -- See [#Bed definition]
45 * `beds.read_spawns() ` Returns a table containing players respawn positions
46 * `beds.kick_players()` Forces all players to leave bed
47 * `beds.skip_night()` Sets world time to morning and saves respawn position of all players currently sleeping
52 description = "Simple Bed",
53 inventory_image = "beds_bed.png",
54 wield_image = "beds_bed.png",
56 bottom = {'Tile definition'}, -- the tiles of the bottom part of the bed.
57 top = {Tile definition} -- the tiles of the bottom part of the bed.
60 bottom = 'regular nodebox', -- bottom part of bed (see [Node boxes])
61 top = 'regular nodebox', -- top part of bed (see [Node boxes])
63 selectionbox = 'regular nodebox', -- for both nodeboxes (see [Node boxes])
64 recipe = { -- Craft recipe
65 {"group:wool", "group:wool", "group:wool"},
66 {"group:wood", "group:wood", "group:wood"}
73 Use `creative.register_tab(name, title, items)` to add a tab with filtered items.
76 creative.register_tab("tools", "Tools", minetest.registered_tools)
78 is used to show all tools. Name is used in the sfinv page name, title is the
81 `is_enabled_for` is used to check whether a player is in creative mode:
83 creative.is_enabled_for(name)
85 Override this to allow per-player game modes.
87 The contents of `creative.formspec_add` is appended to every creative inventory
88 page. Mods can use it to add additional formspec elements onto the default
89 creative inventory formspec to be drawn after each update.
94 The doors mod allows modders to register custom doors and trapdoors.
96 `doors.register_door(name, def)`
99 * `name` Name for door
100 * `def` See [#Door definition]
102 `doors.register_trapdoor(name, def)`
104 * Registers new trapdoor
105 * `name` Name for trapdoor
106 * `def` See [#Trapdoor definition]
108 `doors.register_fencegate(name, def)`
110 * Registers new fence gate
111 * `name` Name for fence gate
112 * `def` See [#Fence gate definition]
116 * `pos` A position as a table, e.g `{x = 1, y = 1, z = 1}`
117 * Returns an ObjectRef to a door, or nil if the position does not contain a door
121 :open(player) -- Open the door object, returns if door was opened
122 :close(player) -- Close the door object, returns if door was closed
123 :toggle(player) -- Toggle the door state, returns if state was toggled
124 :state() -- returns the door state, true = open, false = closed
126 the "player" parameter can be omitted in all methods. If passed then
127 the usual permission checks will be performed to make sure the player
128 has the permissions needed to open this door. If omitted then no
129 permission checks are performed.
133 description = "Door description",
134 inventory_image = "mod_door_inv.png",
135 groups = {choppy = 2},
136 tiles = {"mod_door.png"}, -- UV map.
137 recipe = craftrecipe,
138 sounds = default.node_sound_wood_defaults(), -- optional
139 sound_open = sound play for open door, -- optional
140 sound_close = sound play for close door, -- optional
141 protected = false, -- If true, only placer can open the door (locked for others)
143 ### Trapdoor definition
145 description = "Trapdoor description",
146 inventory_image = "mod_trapdoor_inv.png",
147 groups = {choppy = 2},
148 tile_front = "doors_trapdoor.png", -- the texture for the front and back of the trapdoor
149 tile_side = "doors_trapdoor_side.png", -- the tiles of the four side parts of the trapdoor
150 sounds = default.node_sound_wood_defaults(), -- optional
151 sound_open = sound play for open door, -- optional
152 sound_close = sound play for close door, -- optional
153 protected = false, -- If true, only placer can open the door (locked for others)
155 ### Fence gate definition
157 description = "Wooden Fence Gate",
158 texture = "default_wood.png",
159 material = "default:wood",
160 groups = {choppy = 2, oddly_breakable_by_hand = 2, flammable = 2},
161 sounds = default.node_sound_wood_defaults(), -- optional
166 Allows creation of new fences with "fencelike" drawtype.
168 `default.register_fence(name, item definition)`
170 Registers a new fence. Custom fields texture and material are required, as
171 are name and description. The rest is optional. You can pass most normal
172 nodedef fields here except drawtype. The fence group will always be added
177 name = "default:fence_wood",
178 description = "Wooden Fence",
179 texture = "default_wood.png",
180 material = "default:wood",
181 groups = {choppy = 2, oddly_breakable_by_hand = 2, flammable = 2},
182 sounds = default.node_sound_wood_defaults(),
187 The walls API allows easy addition of stone auto-connecting wall nodes.
189 walls.register(name, desc, texture, mat, sounds)
190 ^ name = "walls:stone_wall". Node name.
191 ^ desc = "A Stone wall"
192 ^ texture = "default_stone.png"
193 ^ mat = "default:stone". Used to auto-generate crafting recipe.
194 ^ sounds = sounds: see [#Default sounds]
199 The farming API allows you to easily register plants and hoes.
201 `farming.register_hoe(name, hoe definition)`
202 * Register a new hoe, see [#hoe definition]
204 `farming.register_plant(name, Plant definition)`
205 * Register a new growing plant, see [#Plant definition]
207 `farming.registered_plants[name] = definition`
208 * Table of registered plants, indexed by plant name
214 description = "", -- Description for tooltip
215 inventory_image = "unknown_item.png", -- Image to be used as wield- and inventory image
216 max_uses = 30, -- Uses until destroyed
217 material = "", -- Material for recipes
218 recipe = { -- Craft recipe, if material isn't used
219 {"air", "air", "air"},
228 description = "", -- Description of seed item
229 inventory_image = "unknown_item.png", -- Image to be used as seed's wield- and inventory image
230 steps = 8, -- How many steps the plant has to grow, until it can be harvested
231 -- ^ Always provide a plant texture for each step, format: modname_plantname_i.png (i = stepnumber)
232 minlight = 13, -- Minimum light to grow
233 maxlight = default.LIGHT_MAX -- Maximum light to grow
239 New node def property:
243 * Called when fire attempts to remove a burning node.
244 * `pos` Position of the burning node.
246 `on_ignite(pos, igniter)`
248 * Called when Flint and steel (or a mod defined ignitor) is used on a node.
249 Defining it may prevent the default action (spawning flames) from triggering.
250 * `pos` Position of the ignited node.
251 * `igniter` Player that used the tool, when available.
254 Give Initial Stuff API
255 ----------------------
257 `give_initial_stuff.give(player)`
259 ^ Give initial stuff to "player"
261 `give_initial_stuff.add(stack)`
263 ^ Add item to the initial stuff
264 ^ Stack can be an ItemStack or a item name eg: "default:dirt 99"
265 ^ Can be called after the game has loaded
267 `give_initial_stuff.clear()`
269 ^ Removes all items from the initial stuff
270 ^ Can be called after the game has loaded
272 `give_initial_stuff.get_list()`
274 ^ returns list of item stacks
276 `give_initial_stuff.set_list(list)`
278 ^ List of initial items with numeric indices.
280 `give_initial_stuff.add_from_csv(str)`
282 ^ str is a comma separated list of initial stuff
283 ^ Adds items to the list of items to be given
288 `nyancat.place(pos, facedir, length)`
290 ^ Place a cat at `pos` facing `facedir` with tail length `length`
291 Only accepts facedir 0-3, if facedir > 3 then it will be interpreted as facedir = 0
293 `nyancat.generate(minp, maxp, seed)`
295 ^ Called by `minetest.register_on_generated`. To disable nyancat generation,
296 you can redefine nyancat.generate() to be an empty function
301 `tnt.register_tnt(definition)`
303 ^ Register a new type of tnt.
305 * `name` The name of the node. If no prefix is given `tnt` is used.
306 * `description` A description for your TNT.
307 * `radius` The radius within which the TNT can destroy nodes. The default is 3.
308 * `damage_radius` The radius within which the TNT can damage players and mobs. By default it is twice the `radius`.
309 * `disable_drops` Disable drops. By default it is set to false.
310 * `ignore_protection` Don't check `minetest.is_protected` before removing a node.
311 * `ignore_on_blast` Don't call `on_blast` even if a node has one.
312 * `tiles` Textures for node
313 * `side` Side tiles. By default the name of the tnt with a suffix of `_side.png`.
314 * `top` Top tile. By default the name of the tnt with a suffix of `_top.png`.
315 * `bottom` Bottom tile. By default the name of the tnt with a suffix of `_bottom.png`.
316 * `burning` Top tile when lit. By default the name of the tnt with a suffix of `_top_burning_animated.png".
318 `tnt.boom(position, definition)`
320 ^ Create an explosion.
322 * `position` The center of explosion.
323 * `definition` The TNT definion as passed to `tnt.register`
325 `tnt.burn(position, [nodename])`
327 ^ Ignite TNT at position, nodename isn't required unless already known.
330 To make dropping items from node inventories easier, you can use the
331 following helper function from 'default':
333 default.get_inventory_drops(pos, inventory, drops)
335 ^ Return drops from node inventory "inventory" in drops.
337 * `pos` - the node position
338 * `inventory` - the name of the inventory (string)
339 * `drops` - an initialized list
341 The function returns no values. The drops are returned in the `drops`
342 parameter, and drops is not reinitialized so you can call it several
343 times in a row to add more inventory items to it.
346 `on_blast` callbacks:
348 Both nodedefs and entitydefs can provide an `on_blast()` callback
350 `nodedef.on_blast(pos, intensity)`
351 ^ Allow drop and node removal overriding
352 * `pos` - node position
353 * `intensity` - TNT explosion measure. larger or equal to 1.0
354 ^ Should return a list of drops (e.g. {"default:stone"})
355 ^ Should perform node removal itself. If callback exists in the nodedef
356 ^ then the TNT code will not destroy this node.
358 `entitydef.on_blast(luaobj, damage)`
359 ^ Allow TNT effects on entities to be overridden
360 * `luaobj` - LuaEntityRef of the entity
361 * `damage` - suggested HP damage value
362 ^ Should return a list of (bool do_damage, bool do_knockback, table drops)
363 * `do_damage` - if true then TNT mod wil damage the entity
364 * `do_knockback` - if true then TNT mod will knock the entity away
365 * `drops` - a list of drops, e.g. {"wool:red"}
371 The screwdriver API allows you to control a node's behaviour when a screwdriver is used on it.
372 To use it, add the `on_screwdriver` function to the node definition.
374 `on_rotate(pos, node, user, mode, new_param2)`
376 * `pos` Position of the node that the screwdriver is being used on
378 * `user` The player who used the screwdriver
379 * `mode` screwdriver.ROTATE_FACE or screwdriver.ROTATE_AXIS
380 * `new_param2` the new value of param2 that would have been set if on_rotate wasn't there
381 * return value: false to disallow rotation, nil to keep default behaviour, true to allow
382 it but to indicate that changed have already been made (so the screwdriver will wear out)
383 * use `on_rotate = false` to always disallow rotation
384 * use `on_rotate = screwdriver.rotate_simple` to allow only face rotation
390 The sethome API adds three global functions to allow mods to read a players home position,
391 set a players home position and teleport a player to home position.
395 * `name` Player who's home position you wish to get
396 * return value: false if no player home coords exist, position table if true
398 `sethome.set(name, pos)`
400 * `name` Player who's home position you wish to set
401 * `pos` Position table containing coords of home position
402 * return value: false if unable to set and save new home position, otherwise true
406 * `name` Player you wish to teleport to their home position
407 * return value: false if player cannot be sent home, otherwise true
415 * sfinv.set_player_inventory_formspec(player, context) - builds page formspec
416 and calls set_inventory_formspec().
417 If context is nil, it is either found or created.
418 * sfinv.get_formspec(player, context) - builds current page's formspec
419 * sfinv.get_nav_fs(player, context, nav, current_idx) - see above
420 * sfinv.get_homepage_name(player) - get the page name of the first page to show to a player
421 * sfinv.make_formspec(player, context, content, show_inv, size) - adds a theme to a formspec
422 * show_inv, defaults to false. Whether to show the player's main inventory
423 * size, defaults to `size[8,8.6]` if not specified
424 * sfinv.register_page(name, def) - register a page, see section below
425 * sfinv.override_page(name, def) - overrides fields of an page registered with register_page.
426 * Note: Page must already be defined, (opt)depend on the mod defining it.
430 * pages - table of pages[pagename] = def
431 * pages_unordered - array table of pages in order of addition (used to build navigation tabs).
432 * contexts - contexts[playername] = player_context
433 * enabled - set to false to disable. Good for inventory rehaul mods like unified inventory
437 A table with these keys:
439 * page - current page name
440 * nav - a list of page names
441 * nav_titles - a list of page titles
442 * nav_idx - current nav index (in nav and nav_titles)
443 * any thing you want to store
444 * sfinv will clear the stored data on log out / log in
446 ### sfinv.register_page
448 sfinv.register_page(name, def)
450 def is a table containing:
452 * `title` - human readable page name (required)
453 * `get(self, player, context)` - returns a formspec string. See formspec variables. (required)
454 * `is_in_nav(self, player, context)` - return true to show in the navigation (the tab header, by default)
455 * `on_player_receive_fields(self, player, context, fields)` - on formspec submit.
456 * `on_enter(self, player, context)` - called when the player changes pages, usually using the tabs.
457 * `on_leave(self, player, context)` - when leaving this page to go to another, called before other's on_enter
461 Use sfinv.make_formspec to apply a layout:
463 return sfinv.make_formspec(player, context, [[
464 list[current_player;craft;1.75,0.5;3,3;]
465 list[current_player;craftpreview;5.75,1.5;1,1;]
466 image[4.75,1.5;1,1;gui_furnace_arrow_bg.png^[transformR270]
467 listring[current_player;main]
468 listring[current_player;craft]
469 image[0,4.25;1,1;gui_hb_bg.png]
470 image[1,4.25;1,1;gui_hb_bg.png]
471 image[2,4.25;1,1;gui_hb_bg.png]
472 image[3,4.25;1,1;gui_hb_bg.png]
473 image[4,4.25;1,1;gui_hb_bg.png]
474 image[5,4.25;1,1;gui_hb_bg.png]
475 image[6,4.25;1,1;gui_hb_bg.png]
476 image[7,4.25;1,1;gui_hb_bg.png]
479 See above (methods section) for more options.
481 ### Customising themes
483 Simply override this function to change the navigation:
485 function sfinv.get_nav_fs(player, context, nav, current_idx)
489 And override this function to change the layout:
491 function sfinv.make_formspec(player, context, content, show_inv, size)
493 size or "size[8,8.6]",
495 sfinv.get_nav_fs(player, context, context.nav_titles, context.nav_idx),
501 return table.concat(tmp, "")
507 The stairs API lets you register stairs and slabs and ensures that they are registered the same way as those
508 delivered with Minetest Game, to keep them compatible with other mods.
510 `stairs.register_stair(subname, recipeitem, groups, images, description, sounds)`
513 * `subname`: Basically the material name (e.g. cobble) used for the stair name. Nodename pattern: "stairs:stair_subname"
514 * `recipeitem`: Item used in the craft recipe, e.g. "default:cobble", may be `nil`
515 * `groups`: see [Known damage and digging time defining groups]
516 * `images`: see [Tile definition]
517 * `description`: used for the description field in the stair's definition
518 * `sounds`: see [#Default sounds]
520 `stairs.register_slab(subname, recipeitem, groups, images, description, sounds)`
523 * `subname`: Basically the material name (e.g. cobble) used for the stair name. Nodename pattern: "stairs:stair_subname"
524 * `recipeitem`: Item used in the craft recipe, e.g. "default:cobble"
525 * `groups`: see [Known damage and digging time defining groups]
526 * `images`: see [Tile definition]
527 * `description`: used for the description field in the stair's definition
528 * `sounds`: see [#Default sounds]
530 `stairs.register_stair_and_slab(subname, recipeitem, groups, images, desc_stair, desc_slab, sounds)`
532 * A wrapper for stairs.register_stair and stairs.register_slab
533 * Uses almost the same arguments as stairs.register_stair
534 * `desc_stair`: Description for stair node
535 * `desc_slab`: Description for slab node
540 Creates panes that automatically connect to each other
542 `xpanes.register_pane(subname, def)`
544 * `subname`: used for nodename. Result: "xpanes:subname" and "xpanes:subname_{2..15}"
545 * `def`: See [#Pane definition]
550 textures = {"texture for sides", (unused), "texture for top and bottom"}, -- More tiles aren't supported
551 groups = {group = rating}, -- Uses the known node groups, see [Known damage and digging time defining groups]
552 sounds = SoundSpec, -- See [#Default sounds]
553 recipe = {{"","","","","","","","",""}}, -- Recipe field only
559 The following nodes use the group `connect_to_raillike` and will only connect to
560 raillike nodes within this group and the same group value.
561 Use `minetest.raillike_group(<Name>)` to get the group value.
563 | Node type | Raillike group name
564 |-----------------------|---------------------
565 | default:rail | "rail"
566 | tnt:gunpowder | "gunpowder"
567 | tnt:gunpowder_burning | "gunpowder"
570 If you want to add a new rail type and want it to connect with default:rail,
571 add `connect_to_raillike=minetest.raillike_group("rail")` into the `groups` table
578 Sounds inside the default table can be used within the sounds field of node definitions.
580 * `default.node_sound_defaults()`
581 * `default.node_sound_stone_defaults()`
582 * `default.node_sound_dirt_defaults()`
583 * `default.node_sound_sand_defaults()`
584 * `default.node_sound_wood_defaults()`
585 * `default.node_sound_leaves_defaults()`
586 * `default.node_sound_glass_defaults()`
587 * `default.node_sound_metal_defaults()`
592 `default.LIGHT_MAX` The maximum light level (see [Node definition] light_source)
597 The player API can register player models and update the player's appearence
599 `default.player_register_model(name, def)`
601 * Register a new model to be used by players.
602 * name: model filename such as "character.x", "foo.b3d", etc.
603 * def: See [#Model definition]
605 `default.registered_player_models[name]`
607 * Get a model's definition
608 * see [#Model definition]
610 `default.player_set_model(player, model_name)`
612 * Change a player's model
613 * `player`: PlayerRef
614 * `model_name`: model registered with player_register_model()
616 `default.player_set_animation(player, anim_name [, speed])`
618 * Applies an animation to a player
619 * anim_name: name of the animation.
620 * speed: frames per second. If nil, default from the model is used
622 `default.player_set_textures(player, textures)`
624 * Sets player textures
625 * `player`: PlayerRef
626 * `textures`: array of textures, If `textures` is nil, the default textures from the model def are used
628 default.player_get_animation(player)
630 * Returns a table containing fields `model`, `textures` and `animation`.
631 * Any of the fields of the returned table may be nil.
637 animation_speed = 30, -- Default animation speed, in FPS.
638 textures = {"character.png", }, -- Default array of textures.
639 visual_size = {x = 1, y = 1}, -- Used to scale the model.
641 -- <anim_name> = {x = <start_frame>, y = <end_frame>},
642 foo = {x = 0, y = 19},
643 bar = {x = 20, y = 39},
651 To enable leaf decay for a node, add it to the `leafdecay` group.
653 The rating of the group determines how far from a node in the group `tree`
654 the node can be without decaying.
656 If `param2` of the node is ~= 0, the node will always be preserved. Thus, if
657 the player places a node of that kind, you will want to set `param2 = 1` or so.
659 The function `default.after_place_leaves` can be set as `after_place_node of a node`
660 to set param2 to 1 if the player places the node (should not be used for nodes
661 that use param2 otherwise (e.g. facedir)).
663 If the node is in the `leafdecay_drop` group then it will always be dropped as an
669 To make recipes that will work with any dye ever made by anybody, define
670 them based on groups. You can select any group of groups, based on your need for
685 * `basecolor_magenta`
687 Extended color groups ( * means also base color )
690 * `excolor_lightgrey`
704 * `excolor_magenta` *
705 * `excolor_red_violet`
707 The whole unifieddyes palette as groups:
709 * `unicolor_<excolor>`
711 For the following, no white/grey/black is allowed:
713 * `unicolor_medium_<excolor>`
714 * `unicolor_dark_<excolor>`
715 * `unicolor_light_<excolor>`
716 * `unicolor_<excolor>_s50`
717 * `unicolor_medium_<excolor>_s50`
718 * `unicolor_dark_<excolor>_s50`
720 Example of one shapeless recipe using a color group:
722 minetest.register_craft({
724 output = '<mod>:item_yellow',
725 recipe = {'<mod>:item_no_color', 'group:basecolor_yellow'},
730 * `dye.basecolors` are an array containing the names of available base colors
732 * `dye.excolors` are an array containing the names of the available extended colors
737 * `default.grow_tree(pos, is_apple_tree)`
738 * Grows a mgv6 tree or apple tree at pos
740 * `default.grow_jungle_tree(pos)`
741 * Grows a mgv6 jungletree at pos
743 * `default.grow_pine_tree(pos)`
744 * Grows a mgv6 pinetree at pos
746 * `default.grow_new_apple_tree(pos)`
747 * Grows a new design apple tree at pos
749 * `default.grow_new_jungle_tree(pos)`
750 * Grows a new design jungle tree at pos
752 * `default.grow_new_pine_tree(pos)`
753 * Grows a new design pine tree at pos
755 * `default.grow_new_acacia_tree(pos)`
756 * Grows a new design acacia tree at pos
758 * `default.grow_new_aspen_tree(pos)`
759 * Grows a new design aspen tree at pos
761 * `default.grow_new_snowy_pine_tree(pos)`
762 * Grows a new design snowy pine tree at pos
768 "mycarts:myrail", -- Rail name
769 nodedef, -- standard nodedef
770 railparams -- rail parameter struct (optional)
774 on_step(obj, dtime), -- Event handler called when
776 acceleration, -- integer acceleration factor (negative
780 The event handler is called after all default calculations
781 are made, so the custom on_step handler can override things
782 like speed, acceleration, player attachment. The handler will
783 likely be called many times per second, so the function needs
784 to make sure that the event is handled properly.
789 The key API allows mods to add key functionality to nodes that have
790 ownership or specific permissions. Using the API will make it so
791 that a node owner can use skeleton keys on their nodes to create keys
792 for that node in that location, and give that key to other players,
793 allowing them some sort of access that they otherwise would not have
794 due to node protection.
796 To make your new nodes work with the key API, you need to register
797 two callback functions in each nodedef:
800 `on_key_use(pos, player)`
801 * Is called when a player right-clicks (uses) a normal key on your
803 * `pos` - position of the node
804 * `player` - PlayerRef
805 * return value: none, ignored
807 The `on_key_use` callback should validate that the player is wielding
808 a key item with the right key meta secret. If needed the code should
809 deny access to the node functionality.
811 If formspecs are used, the formspec callbacks should duplicate these
812 checks in the metadata callback functions.
815 `on_skeleton_key_use(pos, player, newsecret)`
817 * Is called when a player right-clicks (uses) a skeleton key on your
819 * `pos` - position of the node
820 * `player` - PlayerRef
821 * `newsecret` - a secret value(string)
823 * `secret` - `nil` or the secret value that unlocks the door
824 * `name` - a string description of the node ("a locked chest")
825 * `owner` - name of the node owner
827 The `on_skeleton_key_use` function should validate that the player has
828 the right permissions to make a new key for the item. The newsecret
829 value is useful if the node has no secret value. The function should
830 store this secret value somewhere so that in the future it may compare
831 key secrets and match them to allow access. If a node already has a
832 secret value, the function should return that secret value instead
833 of the newsecret value. The secret value stored for the node should
834 not be overwritten, as this would invalidate existing keys.
836 Aside from the secret value, the function should retun a descriptive
837 name for the node and the owner name. The return values are all
838 encoded in the key that will be given to the player in replacement
839 for the wielded skeleton key.
841 if `nil` is returned, it is assumed that the wielder did not have
842 permissions to create a key for this node, and no key is created.