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Reconciles times to always been adjusted to the client timezone

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Fixes #3732
This commit is contained in:
Simone Mainardi 2020-04-20 16:54:25 +02:00
parent 9b061871fa
commit d2aac8cced
2 changed files with 32 additions and 17 deletions
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47
scripts/lua/modules/lua_utils.lua
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@ -2616,28 +2616,43 @@ end
-- ####################################################
-- Converts a string (with the timezone offset) into an epoch
function makeTimeStamp(d, tzoffset)
-- tzoffset is the timezone difference between UTC and Local Time in the browser
-- @brief Converts a datetime string into an epoch, adjusted with the client time
function makeTimeStamp(d)
local pattern = "(%d+)%/(%d+)%/(%d+) (%d+):(%d+):(%d+)"
local day,month, year, hour, minute, seconds = string.match(d, pattern);
local day, month, year, hour, minute, seconds = string.match(d, pattern);
local timestamp = os.time({year=year, month=month, day=day, hour=hour, min=minute, sec=seconds});
-- Get the epoch out of d. The epoch gets adjusted by os.time in the server timezone, that is, in
-- the timezone of this running ntopng instance
-- See https://www.lua.org/pil/22.1.html
local server_epoch = os.time({year = year, month = month, day = day, hour = hour, min = minute, sec = seconds});
-- tprint(string.format("pre-timestamp is %u [%s]", timestamp, formatEpoch(timestamp)))
if tzoffset then
-- from browser local time to UTC
timestamp = timestamp - (tzoffset or 0)
-- Convert the server_epoch into a gmt_epoch which is adjusted to GMT
local gmt_datetable = os.date("!*t", server_epoch)
local gmt_epoch = os.time(gmt_datetable)
-- from UTC to machine local time
local delta = getTzOffsetSeconds()
-- Finally, compute a client_epoch by adding the seconds of getFrontendTzSeconds() to the GMT epoch just computed
local client_datetable = gmt_datetable
client_datetable.sec = client_datetable.sec + getFrontendTzSeconds()
local client_epoch = os.time(client_datetable)
timestamp = math.floor(timestamp + (delta or 0))
-- tprint("delta: "..delta.." tzoffset is: "..tzoffset)
-- tprint(string.format("post-timestamp is %u [%s]", timestamp, formatEpoch(timestamp)))
end
-- Now we can compute the deltas to know the extact number of seconds between the server and the client timezone
local server_to_gmt_delta = gmt_epoch - server_epoch
local gmt_to_client_delta = client_epoch - gmt_epoch
local server_to_client_delta = client_epoch - server_epoch
return string.format("%u", timestamp)
-- Make sure everything is OK...
assert(server_to_client_delta == server_to_gmt_delta + gmt_to_client_delta)
-- tprint({
-- server_ts = server_epoch,
-- gmt_ts = gmt_epoch,
-- server_to_gmt_delta = (server_to_gmt_delta) / 60 / 60,
-- gmt_to_client_delta = (gmt_to_client_delta) / 60 / 60,
-- server_to_client_delta = (server_to_client_delta) / 60 / 60
-- })
-- Return the epoch in the client timezone
return string.format("%u", math.floor(server_epoch - server_to_client_delta))
end
-- ###########################################