add get_thread() that gets all emails, belonging to a certain email

[MoritzFago]

I want to move all anwsered emails with a certain emailadress in cc to another folder, but there is no method to get the answer together with the original email.

[lefcha]

Well you need to write a custom filter function to do this, for example by storing the In-Reply-To header value from the reply, and then searching for a Message-ID that has the same value in your INBOX.

I think I mentioned a similar solution here, too: #174

[doronbehar]

@MoritzFago, I've encountered the need for such a function my self so I wrote this function in my config.lua:

-- {{{1 general function to fetch all messages in a thread
local function get_message_id(msg)
	return msg:fetch_field("Message-ID"):gsub("[Mm]essage%-[Ii][Dd]: ", "")
end
local function get_reply_id(msg)
	return msg:fetch_field("In-Reply-To"):gsub("[Ii]n%-[Rr]eply%-[Tt]o: ", "")
end
function thread_messages(msg, mbox, related_messages, examined_ids)
	-- initilize examined_ids in case it's the first call of this function
	if not examined_ids then examined_ids = {} end
	-- This message
	local this_msgid = get_message_id(msg)
	print("this message's id is " .. this_msgid)
	table.insert(examined_ids, this_msgid)
	print("our known examined_ids are: " .. inspect(examined_ids))
	local this_message = mbox:match_field("Message-ID", this_msgid)
	-- The messages directly replyed to our `msg`
	if related_messages then
		related_messages = related_messages + mbox:match_field("In-Reply-To", this_msgid)
	else
		related_messages = mbox:match_field("In-Reply-To", this_msgid)
	end
	print("found " .. #related_messages .. " messages replyed to it")
	-- The messages our `msg` was replyed to
	local prev_msgid = get_reply_id(msg)
	if string.len(prev_msgid) > 1 then
		print("this message was replied to " .. prev_msgid)
		related_messages = related_messages + mbox:match_field("Message-ID", prev_msgid)
	else
		print("it is not a reply to anything")
	end
	-- Recursively add up messages related in the same way to the related_messages
	for _, related_msg in ipairs(related_messages) do
		local mailbox_related, uid_related = table.unpack(related_msg)
		local related_msgid = get_message_id(mailbox_related[uid_related])
		print("will check for every known related message if the messages replyed to " .. related_msgid .. " have been examined")
		local skip = false
		for i=1,#examined_ids do
			if related_msgid == examined_ids[i] then
				skip = true
			end
		end
		if not skip then
			print("examining new message: " .. related_msgid)
			related_messages = related_messages + thread_messages(mailbox_related[uid_related], mbox, related_messages, examined_ids)
		end
	end
	return related_messages + this_message
end

Note that it is recursive - meaning it calls itself so I'm pretty proud about it you can take out all the print statements` if you want it to be quieter. You are supposed to call it like that:

for _, message in ipairs(account["mailbox"]:contain_somequery("search")) do
	local mailbox, uid = table.unpack(message)
	local all_related_messages = thread_messages(mailbox[uid], mbox)
end

Maybe @lefcha would be willing to make this function a standard method for messages? Anyway, I hope it helps.

[lefcha]

That's quite an interesting way to solve this.

But unfortunately, including this kind of functions would be out-of-scope for imapfilter, and falls more into the different recipes/ways to extend it.

[doronbehar]

No objection @lefcha. Would you be willing to add a WiKi to the repo so I'll be able to add this function there? Or perhaps add a FAQ to the README and link to my comment? I'm suggesting because I do agree with @MoritzFago that this is kind of a basic functionality that is missing from the API.

[lefcha]

@doronbehar The Wiki is a good idea, since any GH user can contribute with config examples, custom functions, build instructions, etc. I enabled it, so feel free to add your pages there.