The following little snippet allows you to ‘pickle’ Lua objects directly into Lua code (with the exception of functions, which are serialized as raw bytecode). Metatable support is on the way, but for now, it should be useful enough.
Example code:
01.dofile "pickle.lua"
02.
03.users = {
04.user1 = {pass = "abcdef", start = 10230},
05.user2 = {pass = "cdefba", start = 12032}
06.}
07.
08.userdump = pickle.dumps(users)
09.print(userdump)
Outputs
01.return {
02.["user1"] = {
03.["pass"] = "abcdef",
04.["start"] = 10230,
05.},
06.["user2"] = {
07.["pass"] = "cdefba",
08.["start"] = 12032,
09.},
10.}
Pickle API:
- pickle.dumps(object) -> String
Pickles an object and returns it. - pickle.dump(object, filename) -> String
Pickles an object and saves it as :filename, afterwards, returns the dump. - pickle.loads(object) -> Lua Object
Loads a string dump of lua object and returns the object. The returned object will not injected into the global table. - pickle.load(filename) -> Lua Object
Loads a pickled object from a file and returns it. The returned object will not be injected into the global table.
Full Source:
01.local objects = {}
02.setmetatable(objects, {__index={["subset"]=function(object, proxies)
03.for _,o in ipairs(proxies) do
04.if object == o then return true end
05.end
06.end}})
07.
08.function _pickle(object, seen, indent)
09.---if not seen then seen = {} end
10.if not indent then indent = "" end
11.
12.local serialize_key = function(key)
13.if type(key) == "string" then
14.return "[\""..key.."\"]"
15.elseif type(key) == "table" then
16.return "[".._pickle(key):gsub("\n"," ").."]"
17.else
18.return "["..key.."]"
19.end
20.return key
21.end
22.
23.local escape = function(o)
24.return o:gsub("\\","\\\\"):gsub("'","\\'"):gsub('"','\\"')
25.end
26.
27.---Switch Object type:
28.if type(object) == "table" then
29.local serialize = "{\n"
30.for key, value in pairs(object) do
31.serialize = serialize .. indent.."\t" .. serialize_key(key) .. " = " ..tostring(_pickle(value, seen, indent.."\t")) .. ",\n"
32.end
33.serialize = serialize .. indent .. "}"
34.
35.return serialize
36.elseif type(object) == "string" then
37.return '"' .. escape(object) .. '"'
38.elseif type(object) == "function" then
39.return "loadstring([["..string.dump(object).."]])"
40.elseif objects.subset(object, {"userdata"}) then
41.return nil
42.end
43.return tostring(object)
44.end
45.
46.pickle = {}
47.
48.function pickle.dumps(object)
49.return "return ".. _pickle(object)
50.end
51.
52.function pickle.dump(object, filename)
53.local dump = pickle.dumps(object)
54.local _file = io.open(filename, "wb")
55._file:write(dump)
56._file:close()
57.return dump
58.end
59.
60.function pickle.loads(object)
61.local fn = loadstring(object)
62.if fn then
63.return fn()
64.end
65.end
66.
67.function pickle.load(filename)
68.local _file = io.open(filename, "rb")
69.local dump = _file:read("*all")
70.local object = pickle.loads(dump)
71._file:close()
72.return object
73.end