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@moteus moteus/sms_bcd2gsm.lua
Last active May 1, 2017

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API command to fix ALPHANUMERIC source numbers received from mod_gsmopen
-- API command to fix ALPHANUMERIC source numbers received from mod_gsmopen
-- Usage: <action application="set" data="from=${lua(sms_bcd2gsm.lua ${from})}" />
-- !! Do not forget that for resending uses not `from` header but `from_full`.
--
-- https://github.com/moteus/lua-tpdu
--
assert(stream, 'this is API command')
local tut = require "tpdu.utils"
local Bit7 = require "tpdu.bit7"
local Bcd = require "tpdu.bcd"
local function split_first(str, sep, plain)
local e, e2 = string.find(str, sep, nil, plain)
if e then
return string.sub(str, 1, e - 1), string.sub(str, e2 + 1)
end
return str
end
-- mod_gsmopen incorrectly decode ALPHANUMERIC numbers as BCD
-- so we revert it back and decode as Bit7/Gsm encoded string
local function fixup_number(number)
-- we really can not be sure what type of number we have because we have no access
-- to TOA structure. So we can only guess
--
-- 1. if string has non digit symbols
-- 2. if string has only hex symbols
-- 3. all symbols in string have same case
-- 4. sting length is even
if string.find(number,'%D')
and string.match(number, '^%x+$')
and ((string.upper(number) == number) or (string.lower(number) == number))
and (#number % 2 == 0)
then
number = Bit7.GsmDecode ( tut.hex2bin( Bcd.Decode(number) ) )
end
return number
end
local function fixup_from(from)
local user, host, proto = split_first(from, '@', true)
proto, user = split_first(user, ':', true)
if not user then user, proto = proto end
user = fixup_number(user)
if host then user = user .. '@' .. host end
if proto then user = proto .. ':' .. user end
return user
end
local number = assert(argv[1])
local fixed = fixup_from(number)
freeswitch.consoleLog('debug', string.format('[sms_bcd2gsm] `%s` => `%s`\n', number, fixed))
stream:write(fixed)
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