如何使用 gmail API 将现有电子邮件发送到新线程

Question

我正在尝试使用 Flask 中的 gmail API 将现有电子邮件发送到另一个线程。

背景： 我创建了一个新的消息对象并成功地使In-Reply-To、References 和threadId 分别等于message_id 和thread_id。 （关注Gmail's API reference）

def create_message(sender, to, subject, thread_id, message_id, message_text, service):
  """Create a message for an email.

  Args:
    sender: Email address of the sender.
    to: Email address of the receiver.
    subject: The subject of the email message.
    message_text: The text of the email message.

  Returns:
    An object containing a base64url encoded email object.
  """
  if type(message_text) != str:
    message_text = str(message_text)

  message = MIMEText(message_text)
  message['to'] = to
  message['from'] = sender
  message['subject'] = subject
  message['In-Reply-To'] = message_id
  message['References'] = message_id
  message['threadId'] = thread_id
  print('created message threadId: %s does == ..' %message['threadId'])
  print(thread_id)

  raw = base64.urlsafe_b64encode(message.as_bytes())
  raw = raw.decode()
  body = {'raw': raw}

  messages = service.users().messages()
  send = messages.send(userId='me', body=body).execute()

问题： 我能够成功地将新邮件发送到我的收件箱，但它们是使用新的threadId 创建的，即使上面代码中的打印语句显示相同的threadId。

然后，当我按照代码示例from this thread：

  body = {'message': {'raw': raw, 'threadId': thread_id}}

我收到以下错误：

googleapiclient.errors.HttpError: <HttpError 400 when requesting https://www.googleapis.com/gmail/v1/users/me/messages/send?alt=json returned "'raw' RFC822 payload message string or uploading message via /upload/* URL required">

问题： 如何生成这些电子邮件，以便它们使用相同的 threadId？

注意：我发现了类似的问题here for javascript和here for java，但没有找到python的答案。

Answer 1

从您提供的链接中的信息可以收集到，您不需要提供In-Reply-To 和References 来启用线程，在请求正文中提供threadId 并使Subject 在documentation 中指定的原始消息正文匹配就足够了。

请进行以下修改：

删除message['threadId'] = thread_id这一行 - threadId 属于请求正文，而不是消息正文

示例：

def create_message(sender, to, subject, thread_id, message_text, service):
  """Create a message for an email.

  Args:
    sender: Email address of the sender.
    to: Email address of the receiver.
    subject: The subject of the email message.
    message_text: The text of the email message.

  Returns:
    An object containing a base64url encoded email object.
  """
  if type(message_text) != str:
    message_text = str(message_text)

  message = MIMEText(message_text)
  message['to'] = to
  message['from'] = sender
  message['subject'] = subject
  raw = base64.urlsafe_b64encode(message.as_bytes())
  raw = raw.decode()
  body = {'raw': raw, 'threadId':thread_id}
  messages = service.users().messages()
  send = messages.send(userId='me', body=body).execute()