require('socket.ftp')
 
-- ftp file
ftpfile = string.format('ftp://ftplogin:ftppassword@192.168.1.11/%s.csv', os.date('%Y-%m-%d_%H-%M'))
-- get past hour data (3600 seconds)
logtime = os.time() - 60 * 60
 
-- list of objects by id
objects = {}
 
-- objects with logging enabled
query = 'SELECT address, datatype, name FROM objects WHERE disablelog=0'
for _, object in ipairs(db:getall(query)) do
  objects[ tonumber(object.address) ] = {
    datatype = tonumber(object.datatype),
    name = tostring(object.name or ''),
  }
end
 
-- csv buffer
buffer = { '"date","address","name","value"' }
 
-- get object logs
query = 'SELECT src, address, datahex, logtime, eventtype FROM objectlog WHERE logtime >= ? ORDER BY id DESC'
for _, row in ipairs(db:getall(query, logtime)) do
  object = objects[ tonumber(row.address) ]
 
  -- found matching object and event type is group write
  if object and row.eventtype == 'write' then
    datatype = object.datatype
 
    -- check that object datatype is set
    if datatype then
      -- decode data
      data = knxdatatype.decode(row.datahex, datatype)
 
      -- remove null chars from char/string datatype
      if datatype == dt.char or datatype == dt.string then
        data = data:gsub('%z+', '')
      -- date to DD.MM.YYYY
      elseif datatype == dt.date then
        data = string.format('%.2d.%.2d.%.2d', data.day, data.month, data.year)
      -- time to HH:MM:SS
      elseif datatype == dt.time then
        data = string.format('%.2d:%.2d:%.2d', data.hour, data.minute, data.second)
      end
    else
      data = ''
    end
 
    -- format csv row
    logdate = os.date('%Y.%m.%d %H:%M:%S', row.logtime)
    csv = string.format('%q,%q,%q,%q', logdate, knxlib.decodega(row.address), object.name, tostring(data))
 
    -- add to buffer
    table.insert(buffer, csv)
  end
end
 
-- upload to ftp only when there's data in buffer
if #buffer > 1 then
  result, err = socket.ftp.put(ftpfile, table.concat(buffer, '\r\n'))
end
 
-- error while uploading
if err then
  alert('FTP upload failed: %s', err)
end