Problems with time zones in Exif data

[stumpigit]

I have noticed that my EXIF data has different formats of the recording time depending on the camera. Sometimes in the format 2024-08-26T13:58:15Z, sometimes 2024-08-26T11:58:15Z+2:00 or then also 2024-08-26T13:58:15.23Z (with milliseconds). Immich itself uses UTC for the search. Lua, on the other hand, works somewhat inconsistently, partly with Local, partly with UTC.

As a result, some of the existing photos are not found. I have now rewritten the checkIfAssetExists so that these types of time specifications are converted to UTC. In addition, one second is added to takenAfter and one less to takenBefore, so that the milliseconds have no influence (as Lua ignores them).

I still think my solution is quite a hack. Should I enter a PR, or do you already have experience with this?

function ImmichAPI:timeStamp(dateStringArg, addSeconds)
    local year, month, day, hour, minute, seconds, offsetsign, offsethour, offsetmin = dateStringArg:match("(%d+)%-(%d+)%-(%d+)%a(%d+)%:(%d+)%:([%d%.]+)([Z%+%- ])(%d?%d?)%:?(%d?%d?)")
    if (year == nil) then
        year, month, day, hour, minute, seconds = dateStringArg:match("(%d+)%-(%d+)%-(%d+)%a(%d+)%:(%d+)%:([%d%.]+)")
        return os.date("!%Y-%m-%dT%TZ",os.time{year = year, month = month, day = day, hour = hour, min = minute, sec = math.floor(seconds) + tonumber(addSeconds)})
    end
    local timestamp = os.time{year = year, month = month, day = day, hour = hour, min = minute, sec = math.floor(seconds) + tonumber(addSeconds)}
    local offset = 0
    if offsetsign ~= 'Z' then
        offset = tonumber(offsethour) * 60 + tonumber(offsetmin)
        if offsetsign == "-" then offset = -offset end
    end
    log:trace(offset)
    return os.date("%Y-%m-%dT%TZ",timestamp - offset * 60)
	
end


function ImmichAPI:checkIfAssetExists(localId, filename, dateCreated)

    local id = tostring(localId)
    log:trace("Trying to get UTC Timestamp from "  .. dateCreated)
    local utcDateCreated = ImmichAPI:timeStamp(tostring(dateCreated),0)    
    log:trace("In timestamp again: " .. utcDateCreated)
    local postBody = { deviceAssetId = id, deviceId = self.deviceIdString, isTrashed = false }
    local response = ImmichAPI:doPostRequest('/search/metadata', postBody)

    if not response then
        log:trace('Asset with deviceAssetId ' .. id .. ' not found. No response')
		return nil
    elseif response.assets.count >= 1 then
        log:trace('Found existing asset with deviceAssetId ' .. tostring(localId))
        return response.assets.items[1].id, response.assets.items[1].deviceAssetId
	else
		log:trace('Asset with deviceAssetId ' .. id .. ' not found')
		
		postBody = { originalFileName = filename, takenAfter = ImmichAPI:timeStamp(tostring(dateCreated),-1), takenBefore = ImmichAPI:timeStamp(tostring(dateCreated),1), isTrashed = false }
		response = ImmichAPI:doPostRequest('/search/metadata', postBody)
		
		if not response then
			log:trace('No asset with originalFilename ' .. filename .. ' and creationDate ' .. utcDateCreated .. ' found')
			return nil
		elseif response.assets.count >= 1 then
			log:trace('Found existing asset with filename  ' .. filename .. ' and creationDate ' ..  utcDateCreated)
			return response.assets.items[1].id, response.assets.items[1].deviceAssetId 
		end
    end
end

[bmachek]

It's quite a hack, yes. But if it works, it's a valuable addition.
Concerning the different date formats, is this an issue at this point? I mean we get the date from Lightroom not from the original file from the camera.
The LRC SDK documentation states

dateCreated: (string) The IPTC-formatted creation date (for example, "2005-09-20T15:10:55Z")

I would interpret ITPC formatted so that it's always the same format.

I think it might be worth a pull request with a little refactoring...