使用 Gmail API 从 Gmail 下载附件

Posted 2023-03-25

【中文标题】使用 Gmail API 从 Gmail 下载附件

【英文标题】：Download attachments from Gmail using Gmail API

【发布时间】：2014-11-08 01:40:26

【问题描述】：

我使用Gmail API 访问我的Gmail 数据和Google Python API client。

根据获取消息的文档附件，他们为 Python 提供了一个 sample。但是我尝试了相同的代码，然后出现错误：

AttributeError: 'Resource' 对象没有属性 'user'

我得到错误的那一行：

message = service.user().messages().get(userId=user_id, id=msg_id).execute()

所以我尝试通过替换user() 来尝试users()：

message = service.users().messages().get(userId=user_id, id=msg_id).execute()

但我在for part in message['payload']['parts'] 中没有收到part['body']['data']。

【参考方案1】：

扩展 @Eric 答案，我从文档中编写了以下 GetAttachments 函数的更正版本：

# based on Python example from 
# https://developers.google.com/gmail/api/v1/reference/users/messages/attachments/get
# which is licensed under Apache 2.0 License

import base64
from apiclient import errors

def GetAttachments(service, user_id, msg_id):
    """Get and store attachment from Message with given id.

    :param service: Authorized Gmail API service instance.
    :param user_id: User's email address. The special value "me" can be used to indicate the authenticated user.
    :param msg_id: ID of Message containing attachment.
    """
    try:
        message = service.users().messages().get(userId=user_id, id=msg_id).execute()

        for part in message['payload']['parts']:
            if part['filename']:
                if 'data' in part['body']:
                    data = part['body']['data']
                else:
                    att_id = part['body']['attachmentId']
                    att = service.users().messages().attachments().get(userId=user_id, messageId=msg_id,id=att_id).execute()
                    data = att['data']
                file_data = base64.urlsafe_b64decode(data.encode('UTF-8'))
                path = part['filename']

                with open(path, 'w') as f:
                    f.write(file_data)

    except errors.HttpError, error:
        print 'An error occurred: %s' % error

【讨论】：

对于那些不能写入文件的人，使用'wb'，因为有时数据不是字符串，它实际上是二进制的。

和内嵌图片？

【参考方案2】：

您仍然可以通过 @Ilya V. Schurov 或 @Cam T 的回答错过附件，原因是电子邮件结构可能会根据 @987654322 有所不同@。

受this answer 的启发，这是我解决问题的方法。

import base64
from apiclient import errors

def GetAttachments(service, user_id, msg_id, store_dir=""):
    """Get and store attachment from Message with given id.
        Args:
            service: Authorized Gmail API service instance.
            user_id: User's email address. The special value "me"
                can be used to indicate the authenticated user.
            msg_id: ID of Message containing attachment.
            store_dir: The directory used to store attachments.
    """
    try:
        message = service.users().messages().get(userId=user_id, id=msg_id).execute()
        parts = [message['payload']]
        while parts:
            part = parts.pop()
            if part.get('parts'):
                parts.extend(part['parts'])
            if part.get('filename'):
                if 'data' in part['body']:
                    file_data = base64.urlsafe_b64decode(part['body']['data'].encode('UTF-8'))
                    #self.stdout.write('FileData for %s, %s found! size: %s' % (message['id'], part['filename'], part['size']))
                elif 'attachmentId' in part['body']:
                    attachment = service.users().messages().attachments().get(
                        userId=user_id, messageId=message['id'], id=part['body']['attachmentId']
                    ).execute()
                    file_data = base64.urlsafe_b64decode(attachment['data'].encode('UTF-8'))
                    #self.stdout.write('FileData for %s, %s found! size: %s' % (message['id'], part['filename'], attachment['size']))
                else:
                    file_data = None
                if file_data:
                    #do some staff, e.g.
                    path = ''.join([store_dir, part['filename']])
                    with open(path, 'w') as f:
                        f.write(file_data)
    except errors.HttpError as error:
        print 'An error occurred: %s' % error

【讨论】：

你是如何处理那些丢失的附件的？我看到的只是一个file_data = None，然后它什么也不做。

看看while 声明，这就是差异的来源。最后一个else: file_data = None 只是为了代码安全。

啊，我明白了，不同的是你还要处理最上层的数据（payload['body']['data']），而其他答案只看部分内的正文（payload['parts']）

'wb' 而不是 'w'

我可以使用您的方法下载 pdf 附件，但是当我打开这些 pdf 时，它们无法打开。我收到错误“打开此文档时出现错误。文件已损坏，无法修复'

【参考方案3】：

我测试了上面的代码，但没有用。我为其他帖子更新了一些东西。 WriteFileError

    import base64
    from apiclient import errors


    def GetAttachments(service, user_id, msg_id, prefix=""):
       """Get and store attachment from Message with given id.

       Args:
       service: Authorized Gmail API service instance.
       user_id: User's email address. The special value "me"
       can be used to indicate the authenticated user.
       msg_id: ID of Message containing attachment.
       prefix: prefix which is added to the attachment filename on saving
       """
       try:
           message = service.users().messages().get(userId=user_id, id=msg_id).execute()

           for part in message['payload'].get('parts', ''):
              if part['filename']:
                  if 'data' in part['body']:
                     data=part['body']['data']
                  else:
                     att_id=part['body']['attachmentId']
                     att=service.users().messages().attachments().get(userId=user_id, messageId=msg_id,id=att_id).execute()
                     data=att['data']
            file_data = base64.urlsafe_b64decode(data.encode('UTF-8'))
            path = prefix+part['filename']

            with open(path, 'wb') as f:
                f.write(file_data)

        except errors.HttpError as error:
            print('An error occurred: %s' % error)

【参考方案4】：

肯定是users()。

响应消息的格式很大程度上取决于您使用的格式参数。如果使用默认值 (FULL)，则部件将具有 part['body']['data']，或者当数据很大时，具有可以传递给 messages().attachments().get() 的 attachment_id 字段。

如果您查看附件文档，您会看到： https://developers.google.com/gmail/api/v1/reference/users/messages/attachments

（如果在主消息文档页面上也提到了这一点，那就太好了。）

【参考方案5】：

我对上面的代码进行了以下更改，并且对于每个包含附件文档的电子邮件 ID 都可以正常工作，我希望这会有所帮助，因为通过 API 示例，您会得到一个错误密钥。

def GetAttachments(service, user_id, msg_id, store_dir):

"""Get and store attachment from Message with given id.

Args:
service: Authorized Gmail API service instance.
user_id: User's email address. The special value "me"
can be used to indicate the authenticated user.
msg_id: ID of Message containing attachment.
prefix: prefix which is added to the attachment filename on saving
"""
try:
    message = service.users().messages().get(userId=user_id, id=msg_id).execute()
    for part in message['payload']['parts']:
        newvar = part['body']
        if 'attachmentId' in newvar:
            att_id = newvar['attachmentId']
            att = service.users().messages().attachments().get(userId=user_id, messageId=msg_id, id=att_id).execute()
            data = att['data']
            file_data = base64.urlsafe_b64decode(data.encode('UTF-8'))
            print(part['filename'])
            path = ''.join([store_dir, part['filename']])
            f = open(path, 'wb')
            f.write(file_data)
            f.close()
except errors.HttpError, error:
    print 'An error occurred: %s' % error

Google Official API for Attachments

【讨论】：

'wb' 而不是 'w'

【参考方案6】：

感谢 @Ilya V. Schurov 和 @Todor 的解答。如果同一搜索字符串有带附件和不带附件的邮件，您仍然可能会错过消息。这是我为两种类型的邮件（即带附件和不带附件）获取邮件正文的方法。

def get_attachments(service, msg_id):
try:
    message = service.users().messages().get(userId='me', id=msg_id).execute()

    for part in message['payload']['parts']:
        if part['filename']:
            if 'data' in part['body']:
                data = part['body']['data']
            else:
                att_id = part['body']['attachmentId']
                att = service.users().messages().attachments().get(userId='me', messageId=msg_id,id=att_id).execute()
                data = att['data']
            file_data = base64.urlsafe_b64decode(data.encode('UTF-8'))
            path = part['filename']

            with open(path, 'wb') as f:
                f.write(file_data)
    

except errors.HttpError as error:
    print ('An error occurred: %s') % error

def get_message(service,msg_id):
try:
    message = service.users().messages().get(userId='me', id=msg_id).execute()
    if message['payload']['mimeType'] == 'multipart/mixed':
        for part in message['payload']['parts']:
            for sub_part in part['parts']:
                if sub_part['mimeType'] == 'text/plain':
                    data = sub_part['body']['data']
                    break
            if data:
                break           
    else:
        for part in message['payload']['parts']:
            if part['mimeType'] == 'text/plain':
                data = part['body']['data']
                break
    
    content = base64.b64decode(data).decode('utf-8')
    print(content)

    return content    

except errors.HttpError as error:
    print("An error occured : %s") %error

【参考方案7】：

from __future__ import print_function
import base64
import os.path
import oauth2client
from googleapiclient.discovery import build
from oauth2client import file,tools
SCOPES = ['https://www.googleapis.com/auth/gmail.readonly']
store_dir=os.getcwd()

def attachment_download():

store = oauth2client.file.Storage('credentials_gmail.json')
creds = store.get()
if not creds or creds.invalid:
    flow = oauth2client.client.flow_from_clientsecrets('client_secrets.json', SCOPES)
    creds = oauth2client.tools.run_flow(flow, store)


try:
    service = build('gmail', 'v1', credentials=creds)
    results = service.users().messages().list(userId='me', labelIds=['XXXX']).execute() # XXXX is label id use INBOX to download from inbox
    messages = results.get('messages', [])
    for message in messages:
        msg = service.users().messages().get(userId='me', id=message['id']).execute()
        for part in msg['payload'].get('parts', ''):

            if part['filename']:
                if 'data' in part['body']:
                    data = part['body']['data']
                else:
                    att_id = part['body']['attachmentId']
                    att = service.users().messages().attachments().get(userId='me', messageId=message['id'],id=att_id).execute()
                    data = att['data']
                file_data = base64.urlsafe_b64decode(data.encode('UTF-8'))

                filename = part['filename']
                print(filename)
                path = os.path.join(store_dir + '\\' 'Downloaded files' + '\\' + filename)

                with open(path, 'wb') as f:
                    f.write(file_data)
                    f.close()
except Exception as error:
    print(error)

请看： 获取标签 ID https://developers.google.com/gmail/api/v1/reference/users/labels/list