Csv file as attachment

[admin]

Create a scheduled script that runs every hour. Modify ids table as needed: key is id in the CSV, value is the trend log name. Also fill in correct mail settings and to variable.

Code:

ids = {
  ['707057500075005871'] = 'Temperature',
  ['213123123123123123'] = 'Humidity',
}

require('trends')

dates = {}
dates['start'] = os.date('*t')
dates['start'].day = dates['start'].day - 1
dates['end'] = os.date('*t')

buf = {}
now = os.time()

for id, tname in pairs(ids) do
  values = trends.fetch(tname, dates)
  count = #values
  step = 86400 / count

  for i, value in ipairs(values) do
    buf[ #buf + 1 ] = {
      now - (count - i) * step,
      id,
      value
    }
  end
end

table.sort(buf, function(a, b)
  return a[ 1 ] > b[ 1 ]
end)

for i, row in ipairs(buf) do
  row[ 1 ] = os.date('%Y-%m-%d %H:%M', row[ 1 ])
  buf[ i ] = table.concat(row, ',')
end

csv = table.concat(buf, '\n')

to = 'to@example.com'

settings = {
  -- "from" field, only e-mail must be specified here
  from = 'sender@example.com',
  -- smtp username
  user = 'sender@example.com',
  -- smtp password
  password = '12345678',
  -- smtp server
  server = 'smtp.gmail.com',
  -- smtp server port
  port = 465,
  -- enable ssl, required for gmail smtp
  secure = 'tlsv1_2',
}

subject = 'CSV'

smtp = require('socket.smtp')
mime = require('mime')
ltn12 = require('ltn12')

function escape(v)
  return '<' .. tostring(v) .. '>'
end

to = escape(to)

msgt = {
  headers = {
    to = to,
    ['content-type'] = 'text/csv',
    ['content-disposition'] = 'attachment; filename="logs.csv"',
    ['content-transfer-encoding'] = 'BASE64',
    subject = subject,
  },
  body = ltn12.source.chain(
    ltn12.source.string(csv),
    ltn12.filter.chain(mime.encode('base64'), mime.wrap('base64'))
  )
}

settings.source = smtp.message(msgt)
settings.from = escape(settings.from)
settings.rcpt = { to }

res, err = smtp.send(settings)
log(res, err)