利用flask-mail实现发送电子邮件

作者:独钓寒江 栏目:后端技术

 

Flask-Mail电子邮件

一、使用Pipenv安装Flask-Mail


pip install Flask-Mail
实例化flask-mail提供的mail类 并传入程序实例以完成初始化，如下所示：

from flask_mail import Mail
app = Flask(__name__)
mail = Mial(app)

 

二、配置Flask_mail

Flask-Mail通过连接SMTP（Simple Mail Transfer Protocol，简单邮件传输协议）服务器来发送邮件。因此，在开始发送电子邮件前，我们需要配置SMTP服务器。如果你的电脑上已经设置好了SMTP服务器，那么无须过多的配置即可使用，默认的邮件服务器配置即为localhost，端口为25。

对发送的邮件进行加密可以避免邮件在发送过程中被第三方截获和篡改。SSL（Security Socket Layer，安全套接字层）和TLS（Transport Layer Security，传输层安全）是两种常用的电子邮件安全协议。
在大多数情况下，名词SSL和TLS可以互换使用。
通过将MAIL_USE_SSL设置为True开启。STARTTLS是另一种加密方式，它会对不安全的连接进行升级（使用SSL或TLS）。尽管它的名字中包含TLS，但也可能会使用SSL加密。根据加密的方式不同，端口也要相应改变，如下所示：


1）SSL/TLS加密：

MAIL_USE_SSL = True
MAIL_PORT = 465

2）STARTTLS加密

MAIL_USE_TLS = True
MAIL_PORT = 587
常用SMTP服务提供商配置
 
# -*- coding: utf-8 -*-

import os
from threading import Thread

import sendgrid
from sendgrid.helpers.mail import Email as SGEmail, Content, Mail as SGMail
from flask_mail import Mail, Message
from flask_wtf import FlaskForm
from wtforms import StringField, TextAreaField, SubmitField
from wtforms.validators import DataRequired, Email
from flask import Flask, flash, redirect, url_for, render_template, request

app = Flask(__name__)
app.jinja_env.trim_blocks = True
app.jinja_env.lstrip_blocks = True

app.config.update(
    SECRET_KEY=os.getenv('SECRET_KEY', 'secret string'),
    MAIL_SERVER=os.getenv('MAIL_SERVER'),
    MAIL_PORT=465,
    MAIL_USE_SSL=True,
    MAIL_USERNAME=os.getenv('MAIL_USERNAME'),
    MAIL_PASSWORD=os.getenv('MAIL_PASSWORD'),
    MAIL_DEFAULT_SENDER=('Grey Li', os.getenv('MAIL_USERNAME'))
)

mail = Mail(app)


# send over SMTP
def send_smtp_mail(subject, to, body):
    message = Message(subject, recipients=[to], body=body)
    mail.send(message)


# send over SendGrid Web API
def send_api_mail(subject, to, body):
    sg = sendgrid.SendGridAPIClient(os.getenv('SENDGRID_API_KEY'))
    from_email = SGEmail('Grey Li ')
    to_email = SGEmail(to)
    content = Content("text/plain", body)
    email = SGMail(from_email, subject, to_email, content)
    sg.client.mail.send.post(request_body=email.get())


# send email asynchronously
def _send_async_mail(app, message):
    with app.app_context():
        mail.send(message)


def send_async_mail(subject, to, body):
    # app = current_app._get_current_object()  # if use factory (i.e. create_app()), get app like this
    message = Message(subject, recipients=[to], body=body)
    thr = Thread(target=_send_async_mail, args=[app, message])
    thr.start()
    return thr


# send email with HTML body
def send_subscribe_mail(subject, to, **kwargs):
    message = Message(subject, recipients=[to], sender='Flask Weekly <%s>' % os.getenv('MAIL_USERNAME'))
    message.body = render_template('emails/subscribe.txt', **kwargs)
    message.html = render_template('emails/subscribe.html', **kwargs)
    mail.send(message)


class EmailForm(FlaskForm):
    to = StringField('To', validators=[DataRequired(), Email()])
    subject = StringField('Subject', validators=[DataRequired()])
    body = TextAreaField('Body', validators=[DataRequired()])
    submit_smtp = SubmitField('Send with SMTP')
    submit_api = SubmitField('Send with SendGrid API')
    submit_async = SubmitField('Send with SMTP asynchronously')


class SubscribeForm(FlaskForm):
    name = StringField('Name', validators=[DataRequired()])
    email = StringField('Email', validators=[DataRequired(), Email()])
    submit = SubmitField('Subscribe')


@app.route('/', methods=['GET', 'POST'])
def index():
    form = EmailForm()
    if form.validate_on_submit():
        to = form.to.data
        subject = form.subject.data
        body = form.body.data
        if form.submit_smtp.data:
            send_smtp_mail(subject, to, body)
            method = request.form.get('submit_smtp')
        elif form.submit_api.data:
            send_api_mail(subject, to, body)
            method = request.form.get('submit_api')
        else:
            send_async_mail(subject, to, body)
            method = request.form.get('submit_async')

        flash('Email sent %s! Check your inbox.' % ' '.join(method.split()[1:]))
        return redirect(url_for('index'))
    form.subject.data = 'Hello, World!'
    form.body.data = 'Across the Great Wall we can reach every corner in the world.'
    return render_template('index.html', form=form)


@app.route('/subscribe', methods=['GET', 'POST'])
def subscribe():
    form = SubscribeForm()
    if form.validate_on_submit():
        name = form.name.data
        email = form.email.data
        send_subscribe_mail('Subscribe Success!', email, name=name)
        flash('Confirmation email have been sent! Check your inbox.')
        return redirect(url_for('subscribe'))
    return render_template('subscribe.html', form=form)


@app.route('/unsubscribe')
def unsubscribe():
    flash('Want to unsubscribe? No way...')
    return redirect(url_for('subscribe'))
 

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