Re: How do you filter the email headers you read from an email folder?

[José Dapena Paz <jdapena igalia com>]

El lun, 28-06-2010 a las 16:07 -0700, Steve Rosen escribió:

> Here's my question - Is there any way to provide a filter that will limit
> the headers that are retrieved from the email server?

	Just, plain and fast, no.

	Tinymail and our camel imap backend work on the assumption of handling
the full folder in the folder summary.

	There has been some work to override this (making the summary only show
the latest N messages of each account), but it was never finished.

> 
> For example, a lot of people will have an inbox folder that has, literally,
> thousands and thousands of messages (going back many years, in some cases) -
> my current strategy is to simply retrieve all the headers, and before I try
> to save off anything that I care about, I make sure the date in the header
> is greater than some specified date in the past (for example, one month 
> ago).
> 
> But - if the inbox folder I am monitoring has thousands and thousands of
> emails, I will receive thousands and thousands of email headers, and only
> choose to keep a few dozen (or, however many were sent in just the last 
> month).

	Yes, remember also that you'll also have those headers in the camel
summary.

> 
> So I'm looking for some way, using the TinyMail APIs, to provide that 
> filtering
> at a lower level, i.e., make sure that my little device (which wants to keep
> bandwidth to an absolute minimum) only tries to retrieve email headers from
> the server that are not older than (in this example) just one month from 
> today.

	The way to fix this is working on these fields:
	1.) Modify the folder summary, to allow it to represent properly "we
have the latest N messages" or "we have the messages since...".
	2.) Adapt the backends (imap, etc), to use this feature.

	Another possibility is working on each camel backend to have a
parameter to show only latest messages, and then store in summary the
latest ones as if they were all the messages. This has the really bad
thing of not showing to user or API user the proper counts of messages,
etc.

> 
> Is this possible?  If so, how?

	So, it's possible. But don't expect it to be easy or fast to fix.