Flask-mail send_async_email() 生成异常和 RunTimeError: Working outside of application context

Posted 2023-02-25

【中文标题】Flask-mail send_async_email() 生成异常和 RunTimeError: Working outside of application context

【英文标题】：Flask-mail send_async_email() generates an exception and RunTimeError: Working outside of application context

【发布时间】：2021-02-12 02:56:54

【问题描述】：

除了 send_email() 之外，整个事情都有效。无论我使用localhost 还是远程主机，我都会遇到同样的异常。我的猜测是我没有将上下文推送到正确的位置，但我已经盯着这个看了很长时间，我显然没有看到错误。任何帮助将不胜感激！

__init__.py:

from flask import Flask, Blueprint, jsonify, ...

from config import config
from flask_login import LoginManager
from extensions import db, mail, moment

login_manager = LoginManager()
login_manager.login_view = 'auth.login'

def create_app():  
    app = Flask(__name__,
                static_url_path='',
                static_folder='../app/static',
                template_folder='../app/templates')

    app.config.from_object(config['default'])
    config['default'].init_app(app)
    
    db.init_app(app)
    mail.init_app(app)
    moment.init_app(app)

    with app.app_context():
        db.create_all()

    migrate = Migrate(app, db)
    from app import models
    
    from .templates.auth import auth_bp
    from .templates.main import main_bp

    app.register_blueprint(main_bp)
    app.register_blueprint(auth_bp, url_prefix='/auth')

    login_manager.init_app(app)

    return app

views.py：

from flask import abort, Blueprint, flash, ...
from flask.globals import current_app
from flask_login import current_user, login_required, login_user, logout_user
from werkzeug.security import generate_password_hash
from datetime import datetime, timezone

from wtforms.validators import UUID

from . import auth_bp

from extensions import db, common_context
from app.models. ...
from .forms import LoginForm, RegistrationForm, ...
from .email import send_email

@auth_bp.route('/register/', methods=['GET', 'POST'], defaults='user_id': None)
def register(user_id):
    from sqlalchemy.exc import IntegrityError
    from .email import send_email

    if current_user.is_authenticated:
        return redirect(url_for('main.home'))
    form=RegistrationForm()

    if form.validate_on_submit():
        try:
            individual = Individual(...
            )
            db.session.add(individual)
            db.session.flush()

            individual_email = Individual_email(...
            )
            db.session.add(individual_email)

            user = User(...
            )
            db.session.add(user)
            db.session.commit()
            token = user.generate_confirmation_token()
            # with current_app.app_context():
            #     print(individual_email.email, user, individual.first_name, token) - this works!!!
            send_email(individual_email.email, 'Please Confirm Your Account',
                   'auth/email/confirm', user=user, token=token, individual=individual)
            flash('A confirmation email has been sent to you by email.')
        except AssertionError as err:
            db.session.rollback()
            abort(409, err) 
        except IntegrityError as err:
            db.session.rollback()
            abort(409, err.orig) 
        except Exception as err:
            db.session.rollback()
            abort(500, err)
        finally:
            db.session.close()
        return redirect(url_for('auth.login'))
    
    context = 
        'form': form,
        'title': 'Registration',
    
    return render_template('auth/register.html', **context, **common_context)

email.py:

from flask import render_template, current_app
from flask_mail import Message
from threading import Thread
from app import mail

def send_async_email(app, msg):
    with app.app_context():
        mail.send(msg)

def send_email(to, subject, template, **kwargs):
    app=current_app
    msg = Message(app.config['MAIL_SUBJECT_PREFIX'] + subject, sender = app.config['MAIL_SENDER'], recipients=[to])
    msg.body = render_template(template + '.txt', **kwargs)
    msg.html = render_template(template + '.html', **kwargs)
    thr = Thread(target=send_async_email, args=[app, msg])
    thr.start()
    return thr

配置：

import os

from dotenv import load_dotenv

basedir = os.path.abspath(os.path.dirname(__file__))
load_dotenv(os.path.join(basedir, '.env'))

class Config(object):
    DEBUG = False
    TESTING = False
    CSRF_ENABLED = True

    SECRET_KEY = os.environ.get('SECRET_KEY')
    SQLALCHEMY_TRACK_MODIFICATIONS = False

    ...

    @staticmethod
    def init_app(app):
        pass

class ProductionConfig(Config):
    DEBUG = False
    SQLALCHEMY_DATABASE_URI = os.environ.get('DATABASE_URI')
    MAIL_SERVER = os.environ.get('MAIL_SERVER', 'smtp.gmail.com')
    MAIL_PORT = int(os.environ.get('MAIL_PORT', '587'))
    MAIL_USE_TLS = os.environ.get('MAIL_USE_TLS', 'true').lower() in \
        ['true', 'on', '1']
    MAIL_USE_SSL = os.environ.get('MAIL_USE_SSL', 'false').lower()
    MAIL_USERNAME = os.environ.get('MAIL_USERNAME')
    MAIL_PASSWORD = os.environ.get('MAIL_PASSWORD')
    MAIL_SUBJECT_PREFIX = '[...]'
    MAIL_SENDER = '... <...>'
    MAIL_ADMIN = os.environ.get('MAIL_ADMIN')

class DevelopmentConfig(Config):
    DEVELOPMENT = True
    DEBUG = True
    SQLALCHEMY_DATABASE_URI = os.environ.get('DEV_DATABASE_URI')

    MAIL_SERVER = 'localhost'
    MAIL_PORT = 25
    MAIL_USE_TLS = False
    MAIL_USE_SSL = False
    # MAIL_DEBUG = app.debug
    MAIL_USERNAME = '...'
    MAIL_PASSWORD = os.environ.get('MAIL_PASSWORD')
    MAIL_DEFAULT_SENDER = '... <...>'
    MAIL_MAX_EMAILS = None
    # MAIL_SUPPRESS_SEND = app.testing
    MAIL_ASCII_ATTACHMENTS = False
    MAIL_SUBJECT_PREFIX = '[...]'
    MAIL_SENDER = '... <...>'
    MAIL_ADMIN = '...'

    config = 
    'development': DevelopmentConfig,
    'testing': TestingConfig,
    'production': ProductionConfig,

    'default': DevelopmentConfig
    

输出：

Exception in thread Thread-23:
Traceback (most recent call last):
  File "C:\...\Python38\lib\threading.py", line 932, in _bootstrap_inner
127.0.0.1 - - [11/Feb/2021 21:04:21] "POST /auth/register/ HTTP/1.1" 302 -
    self.run()
  File "C:\...\Python38\lib\threading.py", line 870, in run
    self._target(*self._args, **self._kwargs)
  File "C:\...\app\templates\auth\email.py", line 7, in send_async_email
    with app.app_context():
127.0.0.1 - - [11/Feb/2021 21:04:21] "GET /auth/login HTTP/1.1" 200 -
  File "c:\...\venv\lib\site-packages\werkzeug\local.py", line 347, in __getattr__
    return getattr(self._get_current_object(), name)
  File "c:\...\venv\lib\site-packages\werkzeug\local.py", line 306, in _get_current_object
    return self.__local()
  File "c:\...\venv\lib\site-packages\flask\globals.py", line 52, in _find_app
    raise RuntimeError(_app_ctx_err_msg)
RuntimeError: Working outside of application context.

This typically means that you attempted to use functionality that needed
to interface with the current application object in some way. To solve
this, set up an application context with app.app_context().  See the
documentation for more information.

【问题讨论】：

create_app 在哪里调用？

在 __init__.py 中。就在问题之上...

你能添加那部分吗？尝试在send_async_email 中调用它并检查它是否正常工作

添加哪一部分？它在那里......对不起，我没有听懂你的问题。

create_app 在 init.py 的顶部初始化。它叫什么名字？我看不到！

【参考方案1】：

将email.py 中的两个函数合二为一以避免上下文问题：

def send_email(to, subject, template, **kwargs):
    app=current_app
    with app.app_context():
        msg = Message(app.config['MAIL_SUBJECT_PREFIX'] + subject, sender = 
              app.config['MAIL_SENDER'], recipients=[to])
        msg.body = render_template(template + '.txt', **kwargs)
        msg.html = render_template(template + '.html', **kwargs)
        Thread(target=mail.send(msg)).start()

第一次尝试效果很好。我查看了其他 *** 帖子并收到了将 create_app 导入此模块的建议。我建议不要这条路线。我有两个实例而不是一个或相同的异常，具体取决于create_app() 调用的位置。