flask_mail 中的 _external=True 是什么意思?

What does _external=True mean in flask_mail?

import os
import secrets
from PIL import Image
from flask import url_for, current_app
from flask_mail import Message
from app import mail


def save_picture(form_picture):
    random_hex = secrets.token_hex(8)
    f_name, f_ext = os.path.splitext(form_picture.filename)
    picture_fn = random_hex + f_ext
    picture_path = os.path.join(current_app.root_path, 'static/profile_pics', picture_fn)
    output_size = (125, 125)
    i = Image.open(form_picture)
    i.thumbnail(output_size)
    i.save(picture_path)
    return picture_fn

def send_reset_email(user):
    token = user.get_reset_token()
    msg = Message('Password Reset Request', sender='noreplies@diemo.hr', recipients=[user.email])
    msg.body = f''' To reset your password, visit the following link:
{url_for('users.reset_token', token=token, **_external=True**)}
If you did not make this request then simply ignore this email and no changes will be made
    '''
    mail.send(msg)

我正在制作一个 Flask 应用程序并学习如何使用 flask_mail 模块发送重置电子邮件,所以我想知道当我将重置 link 在邮件正文中。我在 Google 上搜索过,但没有找到任何内容。提前谢谢你。

_external=True 告诉 Flask 它应该生成一个绝对值 URL,而不是一个相对值 URL。例如,https://example.com/my-page 是绝对值 URL,而 /my-page 是相对值 URL。由于您发送的是电子邮件,您站点中某个页面的亲戚 URL 将无法使用。

您可以在此处查看 url_for 的文档:https://flask.palletsprojects.com/en/1.1.x/api/#flask.url_for

_external – if set to True, an absolute URL is generated. Server address can be changed via SERVER_NAME configuration variable which falls back to the Host header, then to the IP and port of the request.