如何使用 Python 将大文件附加到电子邮件 - Gmail API

Question

我正在尝试发送包含大于 10 MB 且小于 25 MB 限制的附件（最好是多个附件）的电子邮件。我提到 10 MB 的原因是因为它似乎是正常的附加文件方式停止工作并且您得到 Error 10053 时的下限。

我在文档中读到，最好的方法是使用 resumable upload 方法，但我无法让它工作，也无法在 Python 中找到任何好的示例.大多数关于此的 SO 问题只是链接回没有 Python 示例的文档，或者他们的代码导致其他错误。

我正在寻找 Python 中的解释，因为我想确保我理解正确。

我看过的问题：

• Attaching a file using Resumable upload w/ Gmail API
• Gmail Api resumable upload Rest( attachment larger than 5MB)
• using /upload urls with Google API client
• How to upload large messages to Gmail
• Error 10053 When Sending Large Attachments using Gmail API
• Sending email via gmail & python
• MIMEMultipart, MIMEText, MIMEBase, and payloads for sending email with file attachment in Python

代码：

import base64
import json
import os
from email import utils, encoders
from email.message import EmailMessage
from email.mime import application, multipart, text, base, image, audio
import mimetypes

from apiclient import errors
from googleapiclient import discovery, http
from google.oauth2 import service_account

def send_email(email_subject, email_body, email_sender='my_service_account@gmail.com', email_to='', email_cc='', email_bcc='', files=None):

    # Getting credentials
    with open(os.environ.get('SERVICE_KEY_PASSWORD')) as f:
        service_account_info = json.loads(f.read())

    # Define which scopes we're trying to access
    SCOPES = ['https://www.googleapis.com/auth/gmail.send']

    # Setting up credentials using the gmail api
    credentials = service_account.Credentials.from_service_account_info(service_account_info, scopes=SCOPES)

    # This allows us to assign an alias account to the message so that the messages aren't coming from 'ServiceDriod-8328balh blah blah'
    delegated_credentials = credentials.with_subject(email_sender)

    # 'Building' the service instance using the credentials we've passed
    service = discovery.build(serviceName='gmail', version='v1', credentials=delegated_credentials)

    # Building out the email 
    message = multipart.MIMEMultipart()
    message['to'] = email_to
    message['from'] = email_sender
    message['date'] = utils.formatdate(localtime=True)
    message['subject'] = email_subject
    message['cc'] = email_cc
    message['bcc'] = email_bcc
    message.attach(text.MIMEText(email_body, 'html'))


    for f in files or []:
        mimetype, encoding = mimetypes.guess_type(f)

        # If the extension is not recognized it will return: (None, None)
        # If it's an .mp3, it will return: (audio/mp3, None) (None is for the encoding)
        # For an unrecognized extension we set mimetype to 'application/octet-stream' so it won't return None again. 
        if mimetype is None or encoding is not None:
            mimetype = 'application/octet-stream'
        main_type, sub_type = mimetype.split('/', 1)

        # Creating the attachement:
        # This part is used to tell how the file should be read and stored (r, or rb, etc.)
        if main_type == 'text':
            print('text')
            with open(f, 'rb') as outfile:
                attachement = text.MIMEText(outfile.read(), _subtype=sub_type)
        elif main_type == 'image':
            print('image')
            with open(f, 'rb') as outfile:
                attachement = image.MIMEImage(outfile.read(), _subtype=sub_type)
        elif main_type == 'audio':
            print('audio')
            with open(f, 'rb') as outfile:
                attachement = audio.MIMEAudio(outfile.read(), _subtype=sub_type)          
        elif main_type == 'application' and sub_type == 'pdf':   
            with open(f, 'rb') as outfile:
                attachement = application.MIMEApplication(outfile.read(), _subtype=sub_type)
        else:                              
            attachement = base.MIMEBase(main_type, sub_type)
            with open(f, 'rb') as outfile:
                attachement.set_payload(outfile.read())

        encoders.encode_base64(attachement)
        attachement.add_header('Content-Disposition', 'attachment', filename=os.path.basename(f))
        message.attach(attachement)



    media_body = http.MediaFileUpload(files[0], chunksize=500, resumable=True)
    print('Uploading large file...')
    body = {'raw': base64.urlsafe_b64encode(message.as_bytes()).decode()}


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

注意：现在，我在 MediaFileUpload 中使用 files[0]，因为我只使用一个文件进行测试，我只想暂时附加一个文件，直到它工作为止。

错误：

Exception has occurred: ResumableUploadError
<HttpError 400 "Bad Request">
  File "C:\Users\CON01599\AppData\Local\Continuum\anaconda3\Lib\site-packages\googleapiclient\http.py", line 927, in next_chunk
    raise ResumableUploadError(resp, content)
  File "C:\Users\CON01599\AppData\Local\Continuum\anaconda3\Lib\site-packages\googleapiclient\_helpers.py", line 130, in positional_wrapper
    return wrapped(*args, **kwargs)
  File "C:\Users\CON01599\AppData\Local\Continuum\anaconda3\Lib\site-packages\googleapiclient\http.py", line 822, in execute
    _, body = self.next_chunk(http=http, num_retries=num_retries)
  File "C:\Users\CON01599\AppData\Local\Continuum\anaconda3\Lib\site-packages\googleapiclient\_helpers.py", line 130, in positional_wrapper
    return wrapped(*args, **kwargs)
  File "C:\Users\CON01599\Documents\GitHub\pipelines\components\email\send_email.py", line 105, in send_email
    message = (service.users().messages().send(userId='me', body=body, media_body=media_body).execute())

答案：

import base64
import io
import json
import os
from email import utils, encoders
from email.message import EmailMessage
from email.mime import application, multipart, text, base, image, audio
import mimetypes

from apiclient import errors
from googleapiclient import discovery, http
from google.oauth2 import service_account


def get_environment_variables():
    """ Retrieves the environment variables and returns them in
        a dictionary object.
    """
    env_var_dict = {
        'to': os.environ.get('TO'),
        'subject': os.environ.get('SUBJECT'),
        'body': os.environ.get('BODY'),
        'file': os.environ.get('FILE')
    }

    return env_var_dict


def send_email(email_subject, email_body, email_sender='my_service_account@gmail.com', email_to='', email_cc='', email_bcc='', files=None):

    # Pulling in the string value of the service key from the parameter
    with open(os.environ.get('SERVICE_KEY_PASSWORD')) as f:
        service_account_info = json.loads(f.read())

    # Define which scopes we're trying to access
    SCOPES = ['https://www.googleapis.com/auth/gmail.send']

    # Setting up credentials using the gmail api
    credentials = service_account.Credentials.from_service_account_info(service_account_info, scopes=SCOPES)
    # This allows us to assign an alias account to the message so that the messages aren't coming from 'ServiceDriod-8328balh blah blah'
    delegated_credentials = credentials.with_subject(email_sender)
    # 'Building' the service instance using the credentials we've passed
    service = discovery.build(serviceName='gmail', version='v1', credentials=delegated_credentials)

    # Building out the email 
    message = multipart.MIMEMultipart()
    message['to'] = email_to
    message['from'] = email_sender
    message['date'] = utils.formatdate(localtime=True)
    message['subject'] = email_subject
    message['cc'] = email_cc
    message['bcc'] = email_bcc
    message.attach(text.MIMEText(email_body, 'html'))


    for f in files or []:
        f = f.strip(' ')
        mimetype, encoding = mimetypes.guess_type(f)

        # If the extension is not recognized it will return: (None, None)
        # If it's an .mp3, it will return: (audio/mp3, None) (None is for the encoding)
        # For an unrecognized extension we set mimetype to 'application/octet-stream' so it won't return None again. 
        if mimetype is None or encoding is not None:
            mimetype = 'application/octet-stream'
        main_type, sub_type = mimetype.split('/', 1)

        # Creating the attachement:
        # This part is used to tell how the file should be read and stored (r, or rb, etc.)
        if main_type == 'text':
            print('text')
            with open(f, 'rb') as outfile:
                attachement = text.MIMEText(outfile.read(), _subtype=sub_type)
        elif main_type == 'image':
            print('image')
            with open(f, 'rb') as outfile:
                attachement = image.MIMEImage(outfile.read(), _subtype=sub_type)
        elif main_type == 'audio':
            print('audio')
            with open(f, 'rb') as outfile:
                attachement = audio.MIMEAudio(outfile.read(), _subtype=sub_type)          
        elif main_type == 'application' and sub_type == 'pdf':   
            with open(f, 'rb') as outfile:
                attachement = application.MIMEApplication(outfile.read(), _subtype=sub_type)
        else:                              
            attachement = base.MIMEBase(main_type, sub_type)
            with open(f, 'rb') as outfile:
                attachement.set_payload(outfile.read())

        encoders.encode_base64(attachement)
        attachement.add_header('Content-Disposition', 'attachment', filename=os.path.basename(f))
        message.attach(attachement)

    media_body = http.MediaIoBaseUpload(io.BytesIO(message.as_bytes()), mimetype='message/rfc822', resumable=True)
    body_metadata = {} # no thread, no labels in this example

    try:
        print('Uploading file...')
        response = service.users().messages().send(userId='me', body=body_metadata, media_body=media_body).execute()
        print(response)
    except errors.HttpError as error:
        print('An error occurred when sending the email:\n{}'.format(error))


if __name__ == '__main__':

    env_var_dict = get_environment_variables()
    print("Sending email...")
    send_email(email_subject=env_var_dict['subject'], 
            email_body=env_var_dict['body'], 
            email_to=env_var_dict['to'],
            files=env_var_dict['file'].split(','))

    print("Email sent!")

Answer 1

您遇到的问题是您的MediaUpload 是一个附件。

您需要将整个 RFC822 消息作为可恢复的 MediaUpload 上传，而不是将单个附件上传为可恢复的 MediaUpload。

换句话说：

import ...
...
from io import BytesIO
from googleapiclient.http import MediaIoBaseUpload

SCOPES = [ 'scopes' ]

creds = get_credentials_somehow()
gmail = get_authed_service_somehow()

msg = create_rfc822_message(headers, email_body)
to_attach = get_attachment_paths_from_dir('../reports/tps/memos/2019/04')
add_attachments(msg, to_attach)

media = MediaIoBaseUpload(BytesIO(msg.as_bytes()), mimetype='message/rfc822', resumable=True)
body_metadata = {} # no thread, no labels in this example
resp = gmail.users().messages().send(userId='me', body=body_metadata, media_body=media).execute()
print(resp)
# { "id": "some new id", "threadId": "some new thread id", "labelIds": ["SENT"]}

我从您提供的代码中拼凑出来，审查了 this GitHub issue 和 Google 的 Inbox-to-Gmail 电子邮件导入器，特别是 this bit。

在发送对现有邮件的回复时，您几乎肯定会拥有某种元数据，您应该提供这些元数据来帮助 Gmail 跟踪您的新回复和原始对话。也就是说，您将传递信息元数据，而不是空的 body 参数，例如

body_metadata = { 'labelIds': [
                    "your label id here",
                    "another label id" ],
                  'threadId': "some thread id you took from the message you're replying to"
                }

其他好的参考：

• API Client's Gmail PyDoc
• Actual code used

Answer 2

你提到附件大于 10Mb，但你没有提到它小于 25Mb：gmail 有一个限制，附件不能大于 25Mb，所以如果这是你的情况，根本没有办法完成这项工作，因为它超出了 gmail 的限制。

解释可以在here找到。

您能否确认您的附件不是太大？