python - 在后台运行特定的 Django 脚本

Question

我正在开发 Gmail 提取应用程序并使用 Gmail API 从服务器获取邮件。问题在于，即使我在后端框架中使用了线程，邮件的获取时间也太大了。现在我要实现一项功能，建议用户选择批量下载，“一旦您的下载准备就绪，我们就会向您发送邮件”，但为此我想在应用程序中运行下面提到的 download.py树在后台，一旦获取结束，它将被终止。 在代码的最底部，我想向用户发送邮件，告知他们的下载已准备就绪，但尽管我已在 settings.py 中定义了邮件服务器，但它无法正常工作。

下载.py

import httplib2, base64
from stripogram import html2text
from oauth2client.django_orm import Storage
from apiclient.discovery import build
from oauth2client import client

from django.contrib.auth.models import User
from .models import CredentialsModel
from django.conf import settings

from rest_framework.views import APIView
from rest_framework.response import Response
from rest_framework import authentication, permissions
from gextracto import models
from gextracto.models import UserData
from django.core.mail import EmailMessage
from django.core import mail

connection = mail.get_connection()



class ListMails(APIView):
    """
    Gets a list of a specified number mail ids for a particular label
    Extracts the email in the form of plain/text
    The API returns all the extracted mails
    """

    authentication_classes = (authentication.SessionAuthentication,)
    permission_classes = (permissions.IsAuthenticated,)



    def extract_headers(self, message):
        """
        Extract the headers for a single mail and returns it
        {To, From, Subject}
        """

        needed_fields = ('From', 'To', 'Subject')
        return {i['name']:i['value'] for i in  message['payload']['headers'] if i['name'] in needed_fields}





    def get_message_body(self, message):
        """
        Get the body of an email
        Recursively look for the body for different mimetypes
        Returns the body as text/plain
        """

        if 'payload' in message:
            return self.get_message_body(message['payload'])

        elif 'parts' in message:
            return self.get_message_body(message['parts'][0])

        else:
            data = base64.urlsafe_b64decode(message['body']['data'].encode('ASCII'))
            markdown_data = html2text(data)#.decode('utf-8', "replace")
            data = data.replace("\n", "<br/>")

            # return {markdown, html}
            return {'markdown':unicode( markdown_data,"ISO-8859-1"), 'html':unicode(data,"ISO-8859-1")} if markdown_data else {'html':unicode(data,"ISO-8859-1")}




    def message_content_html(self, userId, message_id, service):
        """
        Make queries to get the content for a mail given its message id
        Returns all the content
        """

        content = {'id':message_id}
        # try
        message = service.users().messages().get(userId=userId, id=message_id).execute()

        mimetype = message['payload']['mimeType']

        if mimetype == 'text/html':
            return {}
        #
        else:
            body = self.get_message_body(message)
            if body == "":
                body = "<empty message>"

        headers = self.extract_headers(message)
        content['body'] = body
        content.update(headers)

        return content




    def collect_mails(self, user, messages, service):
        """
        Collect the content for all the mails currently downloaded
        """

        all_messages = []
        try:
            for message in messages:
                content = self.message_content_html(user.username, message['id'], service)
                if content:
                    all_messages.append(content)
            return all_messages

        # return empty list if no messages were downloaded
        except KeyError:
            return []


    def get(self, request, format=None):
        """
        Handles the GET request to get all the mails for a label
        Paginages through the GAPI content if required
        API returns all the messages
        {To, From, Subject, body}
        """

        user = request.user
        storage = Storage(CredentialsModel, 'id', user, 'credential')
        credentials = storage.get()
        http_auth = credentials.authorize(httplib2.Http())
        service = build('gmail', 'v1', http=http_auth)
        user_Id = user.username
        label_id = request.GET['label']

        # try
        # call Google API with a request to get a list of all the labels
        response = service.users().messages().list(userId=user_Id, labelIds=label_id, maxResults=100).execute()

        all_messages = self.collect_mails(user, response['messages'], service)


        if not all_messages:
            return Response([])


        else:
            if 'nextPageToken' in response:
                page_token_flag = True

            # request more more mails if the download limit has not yet been satisfied
                while(page_token_flag):
                    response = service.users().messages().list(userId=user_Id, pageToken=response['nextPageToken'], maxResults=100).execute()
                    all_messages.append(self.collect_mails(user, response['messages'], service))
                    print(all_messages)
                    #for x in range(0,len(all_messages)):
                    #b=all_messages[10]
                    #instance= UserData(user_id=user ,label=label_id, sender = b['From'] , subject=b['Subject'] , body=b['body'])
                    #instance.save()
                    page_token_flag = 'nextPageToken' in response

                    ##
            for x in range(0,len(all_messages)):
                b=all_messages[10]
                instance= UserData(user_id=user ,label=label_id, sender = b['From'] , subject=b['Subject'] , body=b['body'])
                instance.save()
            print ("Hi i am here!!!")    
            email = EmailMessage('Your Download Ready!', 'http://127.0.0.1:8000/admin/gextracto/userdata/', to=[user], connection=connection)
            email.send()
            connection.close()
        return Response(all_messages)

请告诉我如何在后台运行它。如果需要任何其他信息，请询问。谢谢

Answer 1

不知道确切的要求，但我会考虑使用 Celery 来运行后台任务。这种方法允许以 native Django 方式管理所有后脚本事件。

您还可以考虑使用 cron(作为 manage.py 命令)运行 Django 脚本 - 但它可能会导致一些限制。

发送电子邮件失败怎么办 - 相信，发送电子邮件后您不需要关闭连接。通常我使用 send_mail()/send_mass_mail() 函数 - 请检查他们的代码以获得想法。