ItemStackMetaData

ItemStackMetaData is a subclass of MetaData obtained via stack:get_meta() allowing for persistent storage of key-value pairs tied to ItemStacks.

WARNING: ItemStack metadata is serialized with ItemStacks, increasing the ItemString length. Inventories have to store multiple ItemStrings, all of which an attacker will try to get to maximum length. Always limit the size of your ItemStackMetaData to keep inventories sendable.

Special Fields

Description

• description: The description to be shown when hovering over the item (see ItemStack:get_description).
• short_description: A short description of the item (see ItemStack:get_short_description).

Hardware Colorization

• color: ColorString to use for hardware colorization of the stack.
• palette_index: Palette index to use for hardware colorization of the stack (if the stack has a palette).

Count

Requires Minetest 5.6 clients for the count override (older clients will simply show the item count according to the item definition); works on all 5.x servers since it only uses ItemStackMetaData serverside.

count_meta

String to show in inventory lists instead of the item count.

count_alignment

Integer (use with :get_int and :set_int).

Alignment of the displayed item count value is encoded as x_align + 4 * y_align where x_align and y_align are one of:

TIP: Magic numbers make code unreadable. Add an explanatory comment when setting alignment:

local meta = stack:get_meta()
meta:set_string("count_alignment", 3 + 4 * 1) -- aligned to the top-right corner

or use well-named (constant) local variables:

local meta = stack:get_meta()
local align_top_right = 3 + 4 * 1
meta:set_int("count_alignment", align_top_right)

or perhaps wrap this all up in a useful helper:

local vert_align = {
    default = 0,
    top = 1,
    center = 2,
    bottom = 3
}

local horz_align = {
    default = 0,
    left = 1,
    center = 2,
    right = 3
}

local function set_stack_cnt_align(stack, vertically, horizontally)
    stack:get_meta():set_int("count_alignment", horz_align[horizontally] + 4 * vert_align[vertically])
end

set_stack_cnt_align(stack, "top", "right")

Methods

:set_tool_capabilities

Allows overriding the tool capabilities specified in the item definition.

Arguments

• tool_capabilities - nil or a tool capabilities table: Either:
  • nil: Clears the tool capability override, or
  • Tool capabilities table: Overrides the defined tool capabilities (see ItemDefinition for the table format)

NOTE: The corresponding :get_tool_capabilities is not a method of ItemStackMetaData but rather of the "parent" ItemStack.

This article is originally based on an article from the minetest_docs project: ItemStackMetaData.adoc by Lars Müller, licensed under CC-BY 4.0