Lua-mp is a simple C module for Lua to manipulate msgpack encoding/decoding.

The simplest way to install it is using Luarocks:

luarocks install --server=https://luarocks.org/dev lua-mp

Or, just compile the single C file:

# Linux
gcc -o mp.so -O3 -fPIC -shared mp.c
# macOS
gcc -o mp.so -O3 -fPIC -shared -undefined dynamic_lookup mp.c
# Windows
cl /Fe mp.dll /LD /MT /O2 /DLUA_BUILD_AS_DLL /Ipath/to/lua/include mp.c path/to/lua/lib

local mp = require "mp"
local serpent = require "serpent" -- just for print table

local bytes = mp.encode {
  name = "alice",
  phone_list = { "1311234", "1310024" }
}
print(mp.tohex(bytes))

local t = mp.decode(bytes)
print(serpent.block(t))

decode() accepts a string, and optional two pos i and j (based on 1), and a optionl env_handler function for arguments. if there is ext type in msgpack string, the ext_handler will be called with type and value and returns a object for use. if the handler returns nothing, the default type/value table will be used.

It returns the decoded object, and if there is any remain bytes in string, returns the current reading position for next reading. So you can iterate all object in a string using a loop:

local pos = 1
local values = {}
while pos do
  values[#values+1], pos = mp.decode(data, pos)
end

meta type is a table, that has a metatable, which has a field "msgpack.type" with below values:

meta value can get by mp.meta() or mp.array(), mp.map() routines:

-- get a meta value of uint:
local uint = mp.meta("uint", 123)
-- get a array:
local array = mp.array { 1,2,3,4 }
-- set all tables to map:
mp.map(map1, map2, map3)

A handler should first returns a "msgpack.type" string, and if needed, return the actual value to be encoded. for "entension" type, handler should returns both type and value:

local function handler_to_get_a_uint() return "uint", 123 end
local function handler_to_get_a_ext() return "extension", 1, "foo" end
local function handler_to_get_a_true() return "True" end
local function handler_to_another_handler() return "handler", { pack = handler } end