gistfile1.lua

local redis = require "resty.redis"
local ngx_log = ngx.log
local kickout = "kickout."
local kg = "kong."
local logout = "logout"
local setmetatable = setmetatable
local expired_duration = 604800
local _M = {}

local function send_to_stdlog(message)
  return ngx_log(ngx.NOTICE, message)  -- this only works with LuaJIT
end


local function set_device_id(red, sub, device_id)
  local ok, err = red:exists(kg .. sub)
  if err then
      ngx.log(ngx.ERR, "Failed to check exists Redis: ", err)        
  end
  if  ok == 1 then
      return false
  end
  red:set(kg ..sub, device_id, "EX", expired_duration)
  return true
end

function _M:logout_flag(conf, token)
  local red = redis:new()
  local ok, err = red:connect(conf.redis_host, conf.redis_port)
  if not ok then
    ngx.log(ngx.ERR, "Failed to connect to Redis: ", err)
    return err
  end

  red:set(kg .. logout .. token, "1", "EX", expired_duration)  
end

function _M:is_token_active(conf, token)
  local red = redis:new()
  local ok, err = red:connect(conf.redis_host, conf.redis_port)
  if not ok then
    ngx.log(ngx.ERR, "Failed to connect to Redis: ", err)
    return err
  end
  
  local ok, err = red:exists(kg .. logout .. token)
  if err then
    ngx.log(ngx.ERR, "Failed to check exists Redis: ", err)        
  end
  if ok == 1 then
    return false
  end
  return true
end

local function get_old_device_id(red, sub, device_id)
    local value, err = red:get(kg .. sub)     
    return value
end

local function close_redis(red)
  local ok, err = red:set_keepalive(10000, 100)
  if not ok then
    ngx.log(ngx.ERR, "Failed to set Redis connection keepalive: ", err)
  end
end


function _M:device_session(conf, sub, device_id)
  if not conf.is_ban_multi_devices  then
    return nil
  end
  
  -- Create a Redis connection
  local red = redis:new()

  local ok, err = red:connect(conf.redis_host, conf.redis_port)
  if not ok then
    ngx.log(ngx.ERR, "Failed to connect to Redis: ", err)
    return err
  end
  
  local kicked_out_device_ids, err = red:get(kg .. kickout .. sub)
  if err then
    close_redis(red)
    ngx.log(ngx.ERR, "Failed to set kickout to Redis: ", err)
    return err
  end
  if kicked_out_device_ids == ngx.null then
    kicked_out_device_ids = ""
  end
  if not string.find(kicked_out_device_ids, device_id, 1, true)  then    
    local ok = set_device_id(red, sub, device_id)    
    if not ok then
      local old_device_id = get_old_device_id(red, sub, device_id)
      if old_device_id ~= device_id then
        red:set(kg .. sub, device_id, "EX", expired_duration) 
        red:set(kg .. kickout .. sub, kicked_out_device_ids .. "," .. old_device_id, "EX", 300)
        close_redis(red)
        return nil, 200      
      end
    end
  else    
    close_redis(red)
    return nil, 409
  end
  close_redis(red)
  return nil      
end
    

return _M