I am using IMAPClient in my Django email client, and currently I am trying to fetch UIDs of the first fifty messages in a given mailbox by the following code:
server = IMAPClient(HOST, use_uid=True, ssl=True)
server.login(USERNAME, PASSWORD)
server.select_folder(folder_name)
messages = server.search(['NOT DELETED', '1:50'])
response = server.fetch(messages, ['UID'])
I would expect then to fetch the unique message identifier by the following command:
for data in response.items():
data[b'UID']
but I end up with keyerror - data has no key named 'UID'. What am I doing wrong? What is the correct way of getting message UIDs via IMAPClient ?
IMAPClient uses UIDs by default. This means that by default, the message ids returned by search() are UIDs. There is no need to query for UIDs separately.
The use_uid argument to the IMAPClient constructor and the use_uid attribute can be used to switch the behaviour. When use_uid is True all methods that accept or return message ids work with UIDs. fetch() also includes the message sequence as a SEQ item.
When use_uid is False, fetch() accepts message sequences but you can query for UIDs.
Example:
server = IMAPClient(HOST, use_uid=True, ssl=True)
server.login(USERNAME, PASSWORD)
server.select_folder(folder_name)
messages = server.search(...)
# messages contains UIDs
r = server.fetch(messages, [...])
for uid, data in r.items():
print(uid, data[b'SEQ']) # show UID & message sequence
server.use_uid = False
messages = server.search(...)
# messages contains sequence numbers (not UIDs)
r = server.fetch(messages, ['UID'])
for seq, data in r.items():
print(seq, data[b'UID']) # show message sequence & UID
More here: https://imapclient.readthedocs.io/en/2.1.0/concepts.html#message-identifiers