[imp] Attachment sizes and linked attachments

[Jan Schneider]

Zitat von Tim Bannister <Tim.Bannister at manchester.ac.uk>:

>> Jan Schneider schrieb:
>> > the attachment size limits are applied no matter
>> > if the attachments are sent with the message or as linked attachments.
>> ...
>> > Now, wouldn't it make sense to not use the same limits, or maybe even
>> > not use any limits at all, if you send files as linked attachments?
>>
>> It would certainly make sense to provide separate size limits
>> for attachments and linked attachments. Normally, the size limit
>> for linked attachments would be much larger than the limit for
>> RFC-822 attachments.
>>
>>
>> As we had already a "File Transfer" service (akin to Imp's linked
>> attachments) in place, I had to modify imp/templates/compose/compose.inc
>> to adapt it to our situation (no linked attachments, rather a link
>> to our service). One reason not to allow linked attachments were
>> storage, and backup, considerations: Imp's upload drectory can be
>> kept small, and temporary (e. g. a RAM disk), when no linked attachments
>> need to be kept for days, or even weeks.
>>
>> For sites like ours, some configurable backend, or hook interfaces,
>> for the linked attachments would come handy. It would be nice to exploit
>> Imp's user interface for the linked attachments (including a note on
>> the URL, in the message being composed), but still use some external
>> service for the actual storage (and later retrieval) of the files being
>> linked. I had not yet the time to think about the details of this
>> proposition, hence I haven't filed a formal enhancement request. Any
>> ideas?
>>
>> Best wishes,
>>    Otto Stolz
>
> We use a similar configuration here (University of Manchester, UK). Our
> users have storage for mail and for files, both stored centrally. At the
> moment we run IMP on servers which are identical and don't need to
> retain any data beyond the length of the session. Preferences are stored
> in a lightweight database.
>
> To avoid abuse (or misguided over-use), we would want to make "linked
> attachments" count against the sending user's quota until they expire.
> For the most part this wouldn't impact users as they usually retail this
> kind of document long term. It does take the service partly out of the
> scope of Horde / IMP; even if IMP offered something like this, we would
> probably still need to customise it.

This could probably be done with a slightly modified FTP VFS driver  
that uses the user's credentials instead of a central account. You  
have to play with user groups and permissions to make sure that the  
anonymous users can retrieve the data via the attachment script.

Jan.

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