See https://support.delta.chat/t/discussion-how-to-show-error-states/1363/10 <!-- comment -->
It turns out that it's pretty easy to distinguish between lots of states (currently Error/NotConnected, Connecting…, Getting new messages… and Connected). What's not that easy is distinguishing between an actual error and no network, because if the server just doesn't respond, it could mean that we don't have network or that we are trying ipv6, but only ipv4 works.
**WRT debouncing:**
Sending of EVENT_CONNECTIVITY_CHANGED is not debounced, but emitted every time one of the 3 threads (Inbox, Mvbox and Sentbox) has a network error, starts fetching data, or is done fetching data.
This means that it is emitted:
- 9 times when dc_maybe_network() is called or we get network connection
- 12 times when we lose network connection
Some measurements: dc_get_connectivity() takes a little more than 1ms (in my measurements back in March), dc_get_connectivity_html() takes 10-20ms. This means that it's no immmediate problem to call them very often, might increase battery drain though. For the UI it may be a lot of work to update the title everytime; at least Android is smart enough to update the title only once.
Possible problems (we don't have to worry about them now I think):
- Due to the scan_folders feature, if the user has lots of folders, the state could be "Connecting..." for quite a long time, generally DC seemed a little unresponsive to me because it took so long for "Connecting..." to go away. Telegram has a state "Updating..." that sometimes comes after "Connecting...".
To be done in other PRs:
- Better handle the case that the password was changed on the server and authenticating fails, see https://github.com/deltachat/deltachat-core-rust/issues/1923 and https://github.com/deltachat/deltachat-core-rust/issues/1768
- maybe event debouncing (except for "Connected" connectivity events)
fix https://github.com/deltachat/deltachat-android/issues/1760
in most (all?) UIs, import/export works on an already created account,
so, dc_accounts_import_account() does not really help here -
but adds some noise and confusion
eg. as for the other dc_accounts_t functions,
the corrsponding dc_context_t functions must not be called.
if really a new account is required for import,
it seems to be easier to call add_account() before import.
Do not process names, avatars, location XMLs, message signature
etc. for duplicate messages.
Previously only `add_parts` was stopped early, but not
`dc_receive_imf`. Also, `dc_receive_imf` processed From: and To:
fields and applied names to contacts even before checking the
Message-ID.
Fake Message-ID generation procedure is changed to operate on raw
header values to avoid interacting with the database.
as by reviving qr codes,
there may be more than one token for a chat,
ensure, the most recent token and only one token is returned
by the sql-command for looking up tokens
(used for generating new codes)
Raw MIME messages may contain non-ASCII characters. Attempting to
store them as TEXT by using String::from_utf8_lossy results in
non-ASCII characters being replaced with Unicode U+FFFD "REPLACEMENT
CHARACTER" which is later incorrectly decoded when attempting to parse
`mime_headers` content into HTML.
Normally they should not end up in contact requests, but if they do,
we want to show them. Otherwise it is completely impossible to see
them until the chat is moved out of contact requests.
Previously chats created by outgoing classic emails went into contact
requests (deaddrop). Outgoing messages are not shown in contact
requests, so created chat was not shown anywhere. With this fix chat
is created both for outgoing classic emails and outgoing chat emails.
Since classical messages are not deleted when show_emails setting is
set to "0" and remain in the database, they should be shown
somewhere. Otherwise they may reappear later when the setting is
enabled again.
New `dc_msg_is_bot()` C API and corresponding `Message.is_bot()`
Python API can be used to check if incoming message is sent by a bot,
e.g. to avoid two echo bots replying indefinitely to each other.
"Bot" flag is not set for outgoing messages, but may be set for
BCC-self messages. For now documentation says that `dc_msg_is_bot()`
return value is unspecified for outgoing messages. It can be better
specified later if needed for specific applications, e.g. sharing an
account with a helper bot.
the default account created by dc_accounts_new()
is annoying when doing a migrate/import account;
in this case, you must not forget to remove the default account.
in between you have two account,
and accounts are swiched.
it seems to be better
to just call add_account() on a new account object as needed.
systemli.org seems not to include Received: header in messages sent to
self, including BCC-self and messages sent to Saved message chat. This
results in all these messages not being displayed on other devices in
multi-device setting. To work around this problem we restrict draft
detection based on Received: header to classical mails.
Delta Chat already implements proper draft detection based on the
\Draft message flag and \Drafts folder flag. However, Thunderbird does
not set \Draft flag when message is stored as "Template". To make
draft detection for Thunderbird more robust, in case Received: header
check is removed altogether later, we check for X-Mozilla-Draft-Info
header which Thunderbird sets both for "Drafts" and "Templates".
probably they come in by the latest sqlx<->rusqlite moves,
however, as they are followed by subsequent migrations,
that should not have been a big bug in the past
(maybe unless the app was killed at a bad moment)
