如何使用Python将大型文件附加到电子邮件-Gmail API

时间：2019-04-05 19:31:40

标签： python gmail-api email-attachments mime google-api-python-client

我正在尝试发送包含附件（最好是多个附件）的电子邮件，这些附件大于10 MB并且小于25 MB的总限制。我提到10 MB的原因是，这似乎是正常的附加文件方式停止工作并获得Error 10053的下限。

我在文档中已经读到，做到这一点的最佳方法是使用resumable upload方法，但是我无法使其正常工作，也无法找到任何好的例子在Python中。关于此的大多数SO问题都直接链接回没有Python示例的文档，否则它们的代码会导致其他错误。

我正在寻找Python的解释，因为我想确保自己理解正确。

我浏览过的问题：

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，在MediaFileUpload中，我使用的是files[0]，因为我仅使用一个文件进行测试，而现在我只想附加一个文件，直到它起作用为止

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!")

2 个答案:

答案 0 :(得分：2)

You mention the attachment being larger than 10Mb, but you don't mention it being smaller than 25Mb: there's a limitation to gmail that attachments can't be larger than 25Mb, so if this is your case, there's simply no way to get this done, as it is beyond gmail limitations.

The explanation can be found here.

Can you confirm that your attachment is not too large?

答案 1 :(得分：2)

您遇到的问题是您的MediaUpload是单个附件。

您无需将单个附件作为可恢复的MediaUpload上载，而是需要将整个RFC822消息作为可恢复的MediaUpload上载。

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整理了这些内容，审查了this GitHub issue和Google的收件箱到Gmail电子邮件导入程序，特别是this bit。

在发送对现有邮件的回复时，几乎可以肯定，您应该提供某种元数据，以帮助Gmail跟踪您的新回复和原始对话。即，您将传递信息性元数据，例如

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

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