Gmail API (Python) - Unable to add a reply to the thread

Question

I want to add a reply to a gmail thread via the API.

Google says to:

simply add a threadId key paired with a thread ID to a message's metadata, the message object.

And here's what I am trying:

def create_message(sender, to, cc, bcc, subject, message_text, file=None, thread=None):
    message = MIMEMultipart()
    print(thread)
    message['to'] = to
    if cc:
        message['cc'] = cc
    if bcc:
        message['bcc'] = bcc
    if thread:
        message['threadId'] = thread
    message['from'] = sender
    message['subject'] = subject
    msg = MIMEText(message_text, 'html')
    message.attach(msg)
    if file:
        message = attach_file(message, file)
    return {'raw': base64.urlsafe_b64encode(message.as_string().encode()).decode()}

But it isn't working. I'm not sure what to do.

Answer 1

I finally managed to get it working. The threadId needed to be moved from the message dictionary into the output itself.

Hopefully this clears it up for someone else:

def create_message(sender, to, cc, bcc, subject, message_text, file=None, thread=None):
    message = MIMEMultipart()
    message['to'] = to
    if cc:
        message['cc'] = cc
    if bcc:
        message['bcc'] = bcc
    message['from'] = sender
    message['subject'] = subject
    msg = MIMEText(message_text, 'html')
    message.attach(msg)
    if file:
        message = attach_file(message, file)
    output =  {'raw': base64.urlsafe_b64encode(message.as_string().encode()).decode()}
    if thread:
        output['threadId'] = thread
    return output