[OpenWrt-Devel] Support for callable metatable for ubus-lua

[Anton D. Kachalov]

Hello.

I'm newbie in Lua and tries to expose several objects' methods to ubus. In current implementation only function is allowed as methods, but I need to pass objects to such functions. Here is the snippet:

============
local uci = require "uci"
local ubus = require "ubus"
local uloop = require "uloop"

local x = uci.cursor()

uloop.init()

local conn = ubus.connect()
if not conn then
    error("Failed to connect to ubus")
end

local SDRs = { }

for s,e in pairs(x:get_all('SDR')) do
    print('-------- '..s..' --------')
    local t = e['.type']

    local klass = require ("sdr."..t)
    local obj = klass:new(e, true)

    SDRs['SDR.'..e['.name']] = obj:ubus_methods(conn)
end

conn:add(SDRs)

uloop.run()
=================

The klass method ubus_methods returns:

=================
function _M.ubus_methods(self, conn)
    local _g = setmetatable({_o = self, _conn = conn}, {
        __call = function(tbl, req, msg)
            tbl._conn:reply(req, { rpm = tbl._o:get() })
        end})

    local _s = setmetatable({_o = self, _conn = conn}, {
        __call = function(tbl, req, msg)
            tbl._conn:reply(req, { status = tbl._o:set(tonumber(msg['duty'])) })
        end})

    local _f = setmetatable({_o = self, _conn = conn}, {
        __call = function(tbl, req, msg)
            tbl._conn:reply(req, { status=tbl._o:fanmap() })
        end})

    return {
        get = { _g, { } },
        set = { _s, { duty = ubus.INT32 } },
        fanmap = { _f, { } }
    }
end
=================

So, I wrote a little patch to add additional check for "__call" metamethod to make it possible.

BTW. There is no code to check signatures (policy) of methods for Lua code.

-- 
Anton D. Kachalov
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