在 flask 中刷新页面时如何更改为消息？

Question

app.py is: In this I am using yash and yash as default username and password and the html page print's "Invalid Credential's" when I enter wrong password and enter it. app.py 是：在此我使用 yash 和 yash 作为默认用户名和密码，当我输入错误密码并输入密码时，html 页面打印“无效凭据”。 But when I refresh after getting invalid credential's also it show's the same index.html page with "Invalid Credential's" Message.但是，当我在获得无效凭据后刷新时，它也显示相同的 index.html 页面，其中显示“无效凭据”消息。 What can I do to show empty login page when I refresh the page from browser.当我从浏览器刷新页面时，我该怎么做才能显示空的登录页面。

import flask
app = flask.Flask(name)
u_p={'yash':'yash'}
@app.route('/user/<name>')
def hello_user(name):
    return flask.render_template('hello.html',uname=name)
@app.route('/', methods=['GET', 'POST'])
def index():
    message = ''
    if flask.request.method == 'POST':
        username=flask.request.form['name-input']
        passowrd=flask.request.form['name-password']
        if u_p.get(username,'')==passowrd:
            return flask.redirect(flask.url_for('hello_user',name=username))
        else:
            message='Invalid Credentials'
    return flask.render_template('index.html', message=message)
if name == 'main':
    app.run()

My index.html is:我的 index.html 是：

<!DOCTYPE html>

<html>
    <head>
        <title>Simple Flask App</title>
        <link rel="shortcut icon" href="{{url_for('static', filename='favicon.png')}}" type="image/x-icon">
    </head>
    <body>
        <h1>Login</h1>
        <form method="POST">
            username <input type="text" name="name-input"><br>
            password <input type="password" name="name-password"><br>
            <button type="submit">Submit</button>
        </form>
        <h2>New User : </h2>
        <button type="submit">Register</button>
        <p>{{message}}</p>
    </body>
</html>

Answer 1

The problem is that if you refresh the page, the browser sends the same POST request again, so it's like you've tried to log in with the same wrong credentials again.问题是，如果您刷新页面，浏览器会再次发送相同的 POST 请求，因此就像您再次尝试使用相同的错误凭据登录一样。

You can get around this by redirecting to index if the credentials are wrong - but then you can't pass along the message as a template argument.如果凭据错误，您可以通过重定向到索引来解决此问题 - 但是您不能将消息作为模板参数传递。

Luckily, flask offers Message Flashing exactly for this purpose: https://flask.palletsprojects.com/en/2.0.x/patterns/flashing/幸运的是，flask 正好为此目的提供消息闪烁： https://flask.palletsprojects.com/en/2.0.x/patterns/flashing/

So your code could look something like this:所以你的代码可能看起来像这样：

import flask
name = "main"
app = flask.Flask(name)
app.secret_key = "SECRET!"
u_p={'yash':'yash'}
@app.route('/user/<name>')
def hello_user(name):
    return flask.render_template('hello.html',uname=name)
@app.route('/', methods=['GET', 'POST'])
def index():
    if flask.request.method == 'POST':
        username=flask.request.form['name-input']
        passowrd=flask.request.form['name-password']
        if u_p.get(username,'')==passowrd:
            return flask.redirect(flask.url_for('hello_user',name=username))
        else:
            flask.flash("Invalid Credentials")
            return flask.redirect(flask.url_for("index"))
    return flask.render_template('index.html')
if name == 'main':
    app.run()

index.html索引.html

<!DOCTYPE html>

<html>
    <head>
        <title>Simple Flask App</title>
        <link rel="shortcut icon" href="{{url_for('static', filename='favicon.png')}}" type="image/x-icon">
    </head>
    <body>
        <h1>Login</h1>
        <form method="POST">
            username <input type="text" name="name-input"><br>
            password <input type="password" name="name-password"><br>
            <button type="submit">Submit</button>
        </form>
        <h2>New User : </h2>
        <button type="submit">Register</button>
        {% with messages = get_flashed_messages() %}
            {% for message in messages %}
                <p>{{message}}</p>
            {% endfor %}
        {% endwith %}
    </body>
</html>

As a side note: The way you check the username and password, someone can log in with a random username and an empty password.附带说明：检查用户名和密码的方式是，有人可以使用随机用户名和空密码登录。

在 flask 中刷新页面时如何更改为消息？

问题描述

1 个解决方案

解决方案1
0 2022-02-01 15:19:36

在 flask 中刷新页面时如何更改为消息？

问题描述

1 个解决方案

解决方案1 0 2022-02-01 15:19:36

解决方案1
0 2022-02-01 15:19:36