[AndrewD]

Originally Posted by rin

Hello Andrew. I am not sure, about the addon LDM. Currently I am serving more than 120.000 attachments (100+ GB) and how I understand LDM, it will only account for the attachments uploaded after the addon has been activated.
Seeing how many attachments I am serving, I would prefer to have the limit as simple as possible. Only adding a new row to all members, summing and controlling their bandwidth usage that way.

--------------- Added [DATE]1250388287[/DATE] at [TIME]1250388287[/TIME] ---------------

Please bear with me. Since I have asked for an addon like this for several days and so far no one else sees its uses, I might want to try and code it myself with my rather limited knowledge of php and mysql.
So if I want to start, I would like to ask you some questions.
The hook to be used for an addon like this should be attachment_start, right?
Then I want to write the code similar to this:

GET attachment-filesize -> write filesize to member download quota table

check member-usergroup; if is member of X usergroup = limit quota->X bytes
if member-download-quota > usergroup-limit THEN stop and write attachment quota message.
if member-download-quota <= usergroup limit THEN go on.

Additionally, I would set up a cron job that runs for example, every 24 hours and clears the member-download-quota table so the member is able to download again.

Is it a good approach?

--------------- Added [DATE]1250393636[/DATE] at [TIME]1250393636[/TIME] ---------------

So far, I got this:

if($vbulletin-userinfo['usergroupid'] = 7) { $download_quota = 15728640; }   // Moderators
if($vbulletin-userinfo[download_quota'] < $download_quota)
{
$new_download_quota = $vbulletin-userinfo['download_quota'] + $attachmentinfo['filesize'];

$db->query_write("
			UPDATE " . TABLE_PREFIX . "user SET
				download_quota = $new_download_quota
			WHERE userid = $vbulletin-userinfo[userid]
			")
}
else
{
print "error";
}

First I create a new table in user called "download_quota".
Then I set a different download quota for all existing usergroups. In this case it's 15 MB in bytes.
Then I go check if the users current download_quota is less than the allowed 15MB.
If that is the case, I will add the filesize of the current attachment to the download_quota field for the specific user.
If it's bigger I return error. =)
Is it that simple?

Your approach looks broadly ok, but my experience is that you will find complications. For example, users can be members of multiple usergroups - which one defines their quota? What happens if a transfer fails to complete? Are you happy with just knowing each user's total transfer or do you want information on the specific files that were downloaded? etc, etc. It's worth thinking these points through before writing any code, just to be clear in your own mind about the consequences of alternative approaches.

I'm not sure of the need for a separate table for the user group allowances, although this is a straightforward solution. Another approach would be to hold this array as a serialised string in the data cache. This would reduce the required sql traffic.