This is broken since 44227d7b86
mimeparser only recognizes read receipts
by the Content-Type being "multipart/report".
If multipart/report is hidden inside multipart/mixed
and the message is not encrypted,
it degrades encryption.
a27e84ad89 "fix: Delete received outgoing messages from SMTP queue"
can break sending messages sent as several SMTP messages because they have a lot of recipients:
`pub(crate) const DEFAULT_MAX_SMTP_RCPT_TO: usize = 50;`
We should not cancel sending if it is such a message and we received BCC-self because it does not
mean the other part was sent successfully. For this, split such messages into separate jobs in the
`smtp` table so that only a job containing BCC-self is canceled from `receive_imf_inner()`. Although
this doesn't solve the initial problem with timed-out SMTP requests for such messages completely,
this enables fine-grained SMTP retries so we don't need to resend all SMTP messages if only some of
them failed to be sent.
The bug was made in 44227d7b86. Sql::execute() with placeholders must
be used to escape strings, one never should escape them manually as strings themselves can contain
escape symbols. Thanks to @link2xt for noticing.
Some SMTP servers are running slow before-queue filters, most commonly Postfix with `rspamd` filter
which is implemented as a [before-queue Milter](https://www.postfix.org/MILTER_README.html). Some of
`rspamd` plugin filters are slow on large mails.
We previously had problems with timing out during waiting for SMTP response:
https://github.com/deltachat/deltachat-core-rust/issues/1383. This is largely fixed by
https://github.com/async-email/async-smtp/pull/29 and currently we have 60-second timeout just for
reading a response but apparently it is not sufficient -- maybe connection gets killed by NAT while
we are waiting for response or `rspamd` takes more than 60 seconds for large messages.
As a result a message is resent multiple times and eventually fails with "too many retries" while
multiple BCC-self messages are received.
We should remove the message from the SMTP queue as soon as we receive it via IMAP as it is clear
the message was sent even if we did not manage to get actual SMTP server response.
First of all, it's just downloaded and hasn't been seen yet by the user. Also this changes nothing
as `msgs.state` isn't changed when replacing a message anyway.
Put a copy of Message-ID into hidden headers and prefer it over the one in the IMF header section
that servers mess up with.
This also reverts "Set X-Microsoft-Original-Message-ID on outgoing emails for amazonaws (#3077)".
As ratelimit was introduced to avoid reconnecting immediately after disconnecting
in case of bugs in IMAP protocol handling,
connection attempts should only be counted when IMAP is actually used,
i.e. when the first command (LOGIN) is sent.
As per the comment in `receive_imf.rs`, `chat.protected` must be maintained regardless of the
`Config::VerifiedOneOnOneChats`. The only thing that mustn't be done if `VerifiedOneOnOneChats` is
unset (i.e. for non-supporting UIs) is marking chats as "protection broken" because this needs
showing the corresponding dialog to a user.
Drafts mustn't affect sorting of any other messages, they aren't even displayed in the chat
window. Also hidden messages mustn't affect sorting of usual messages. But let hidden messages sort
together with protection messages because hidden messages also can be or not be verified, so let's
preserve this information -- even it's not useful currently, it can be useful in the future
versions.
Before in some places it was correctly calculated by passing the "sent" timestamp to
`calc_sort_timestamp()`, but in other places just the system time was used. In some complex
scenarios like #5088 (restoration of a backup made before a contact verification) it led to wrong
sort timestamps of protection messages and also messages following by them.
But to reduce number of args passed to functions needing to calculate the sort timestamp, add
message timestamps to `struct MimeMessage` which is anyway passed everywhere.
We do not want all_work_done() to return true immediately
after calling start_io(), but only when connection goes idle.
"Connected" state is set immediately after connecting to the server,
but it does not mean there is nothing to do.
This change make all_work_done() return false
from the Connected state and introduces a new Idle
connectivity state that is only set before connection
actually goes idle. For idle state all_work_done() returns true.
From the user point of view both old Connected state
and new Idle state look the same.
This change depends on async-imap update that resets the timeout
every time an `* OK Still here` is received.
Reducing timeout allows to detect lost connections
not later than 6 minutes
because Delta Chat will attempt to finish IDLE with DONE
after 5 minutes without keepalives
and will either get TCP RST directly
or, worst case, wait another minute for TCP socket read timeout.
