Hotkey enumeration via obs_enum_hotkeys

TriggerHotkeyByName.lua

local obs = obslua
local ffi = require 'ffi'
local obsffi
if ffi.os == "OSX" then
  obsffi = ffi.load("obs.0.dylib")
else
  obsffi = ffi.load("obs")
end

ffi.cdef[[
typedef struct obs_hotkey obs_hotkey_t;
typedef size_t obs_hotkey_id;

const char *obs_hotkey_get_name(const obs_hotkey_t *key);
typedef bool (*obs_hotkey_enum_func)(void *data, obs_hotkey_id id, obs_hotkey_t *key);
void obs_enum_hotkeys(obs_hotkey_enum_func func, void *data);
]]
function trigger()
  local target = 'OBSBasic.StartVirtualCam'
  local htk_id 
  function callback_htk(data,id,key)
    local name = obsffi.obs_hotkey_get_name(key)
    if ffi.string(name) == target then -- (1)
      htk_id = tonumber(id) -- (2)
      print('found target hotkey id: ' .. htk_id)
      return false
    else
      return true
    end
  end
  local cb = ffi.cast("obs_hotkey_enum_func",callback_htk) -- (3)
  obsffi.obs_enum_hotkeys(cb,data)
  if htk_id then
    obs.obs_hotkey_trigger_routed_callback(htk_id,false)
    obs.obs_hotkey_trigger_routed_callback(htk_id,true) -- (4)
    obs.obs_hotkey_trigger_routed_callback(htk_id,false)
  end
end

function htk_1_cb(pressed)
  if pressed then
    trigger()
  end
end

key_1 = '{"htk_1": [ { "key": "OBS_KEY_1" } ]}'
json_s = key_1 
default_hotkeys = {
  {id='htk_1',des='launch virtual cam',callback=htk_1_cb},
}

function script_load(settings)

  s = obs.obs_data_create_from_json(json_s)
  for _,v in pairs(default_hotkeys) do
    local a = obs.obs_data_get_array(s,v.id)
    h = obs.obs_hotkey_register_frontend(v.id,v.des,v.callback)
    obs.obs_hotkey_load(h,a)
    obs.obs_data_array_release(a)
  end
  obs.obs_data_release(s)
end

See details here https://obsproject.com/forum/threads/tips-and-tricks-for-lua-scripts.132256/#post-492998