我無法解決這個錯誤：jinja2.exceptions.UndefinedError:'user'isundefined-有解無憂

我是 python 和 html 的初學者（因此代碼混亂），我一直在從各種教程中獲取一些資訊，并將它們拼湊在一起。我正在嘗試創建一個網頁，有人可以在上面創建帳戶，編輯所述帳戶，并登錄到所述帳戶，這會將他們帶到主頁。我已經讓編輯頁面正常作業，但其他頁面拋出此錯誤：jinja2.exceptions.UndefinedError: 'user' is undefined。我想我已經將用戶變數傳遞給所有必要的模板，所以我不明白為什么會出現這個錯誤。

這是我的代碼：

主檔案

from flask import Flask, render_template, url_for, request, flash, redirect, abort
import sqlite3
app = Flask(__name__)

def get_db_connection():
    conn = sqlite3.connect('database.db')
    conn.row_factory = sqlite3.Row
    return conn

def get_user(user_id):
    conn = get_db_connection()
    user = conn.execute('SELECT * FROM users WHERE id = ?',(user_id,)).fetchone()
    conn.close()
    if user is None:
        abort(404)
    return user

app.config['SECRET_KEY'] = '013ecbdd4aae3899c7feed1bf36dee4e'

@app.route("/home")
def home():
    conn = get_db_connection()
    user = conn.execute('SELECT * FROM users').fetchall()
    conn.close()
    return render_template('home.html', user=user)

@app.route("/")
@app.route("/about")
def about():
    return render_template('about.html')

@app.route("/register", methods=('GET', 'POST'))
def register():
    if request.method == 'POST':
        username = request.form['username']
        password1 = request.form['password1']
        password2 = request.form['password2']
        if not username:
            flash('Username is required!')
        elif not password1:
            flash('Password is required!')
        elif not password2:
            flash('Valdiated password is required!')
        elif password1 != password2:
            flash('Passwords do not match!')
        else:
            conn = get_db_connection()
            conn.execute('INSERT INTO users (username, password1) VALUES (?, ?)',(username, password1))
            conn.commit()
            conn.close()
            return redirect(url_for('home'))
    return render_template('register.html', title = 'Register')

@app.route("/login")
def login():
    return render_template('login.html', title = 'Login')

@app.route("/<int:id>/edit", methods=('GET', 'POST'))
def edit(id):
    user = get_user(id)
    if request.method == 'POST':
        username = request.form['username']
        password1 = request.form['password1']
        password2 = request.form['password2']
        if not username:
            flash('Username is required!')
        elif not password1:
            flash('Password is required!')
        elif not password2:
            flash('Valdiated password is required!')
        elif password1 != password2:
            flash('Passwords do not match!')
        else:
            conn = get_db_connection()
            conn.execute('UPDATE users SET username = ?, password1 = ?'
                         ' WHERE id = ?',
                         (username, password1, id))
            conn.commit()
            conn.close()
            return redirect(url_for('home'))

    return render_template('edit.html', user=user)

if __name__ == '__main__':
    app.run(debug=True)

布局.html

<html>
<head>
     <meta charset="utf-8">
     <meta name="viewport" content="width=device-width, initial-scale=1, shrink-to-fit=no">
 
     <link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/4.0.0/css/bootstrap.min.css" integrity="sha384-Gn5384xqQ1aoWXA 058RXPxPg6fy4IWvTNh0E263XmFcJlSAwiGgFAW/dAiS6JXm" crossorigin="anonymous">
 
     <link rel= "stylesheet" type= "text/css" href= "{{ url_for('static',filename='styles/main.css') }}">
<title>
    {% block title %} {% endblock %} - FlaskApp</title>
</title>
</head>
<body>
<div id="wrapBanner"> 
<img src="/static/test-photo1.jpg" alt="image not available" id="logo"/>
<div id="topBanner">
    <h2><b>title of web page</b></h2>
    <h4><b>subtitle</b></h4>
</div>
</div>
<div id="navBanner">
    <h3> 
    <a class="nav-link" href="{{ url_for('login') }}">Login</a>
    <a class="nav-link" href="{{ url_for('register') }}">Register</a>
    <a class="nav-link" href="{{ url_for('edit', id=user['id']) }}">Edit Account</a>
    </h3>
</div>
<div id="mainBanner">
    {% for message in get_flashed_messages() %}
            <div class="alert">{{ message }}</div>
        {% endfor %}
    {% block content %} {% endblock %}
</div>
<div id="footerBanner">
    <h4> 
    footer 
    </h4>
</div>
</body>
</html>

編輯.html

{% extends "layout.html" %}
{% block content%}
    <h1>{% block title %} Edit Account "{{ user['username'] }}" {% endblock %}</h1>
    <form method="post">
        <label for="username">New Username</label>
        <br>
        <input type="text" name="username"
            placeholder="Username"
            value="{{ request.form['username'] or user['username'] }}"></input>
        <br>
        
        <label for="password1"> New Password</label>
        <br>
        <input type="text" name="password1"
            placeholder="Password"
            value="{{ request.form['password1'] or user['password1'] }}"></input>
        <br>

        <label for="password2">Validate Password</label>
        <br>
        <input type="text" name="password2"
            placeholder="Validate Password"
            value="{{ request.form['password2'] or user['password1'] }}"></input>
        <br>
        <br>

        <button class="button" type="submit">Submit</button>
    </form>
{% endblock content %}

注冊.html

{% extends "layout.html" %}
{% block content%}
    <h1>{% block title %} Make an account {% endblock %}</h1>
    <form method="post">
        <label for="username">Username</label>
        <br>
        <input type="text" name="username"
            placeholder="Username"
            value="{{ request.form['username'] }}"></input>
        <br>
        
        <label for="password1">Password</label>
        <br>
        <input type="text" name="password1"
            placeholder="Password"
            value="{{ request.form['password1'] }}"></input>
        <br>

        <label for="password2">Validate Password</label>
        <br>
        <input type="text" name="password2"
            placeholder="Validate Password"
            value="{{ request.form['password2'] }}"></input>
        <br>
        <br>

        <button class="button" type="submit">Submit</button>
    </form>
{% endblock content %}

追溯：

Traceback (most recent call last):
  File "c:\Users\EzraLamdin\projectRoster\.venv\lib\site-packages\flask\app.py", line 2095, in __call__
    return self.wsgi_app(environ, start_response)
  File "c:\Users\EzraLamdin\projectRoster\.venv\lib\site-packages\flask\app.py", line 2080, in wsgi_app
    response = self.handle_exception(e)
  File "c:\Users\EzraLamdin\projectRoster\.venv\lib\site-packages\flask\app.py", line 2077, in wsgi_app
    response = self.full_dispatch_request()
  File "c:\Users\EzraLamdin\projectRoster\.venv\lib\site-packages\flask\app.py", line 1525, in full_dispatch_request
    rv = self.handle_user_exception(e)
  File "c:\Users\EzraLamdin\projectRoster\.venv\lib\site-packages\flask\app.py", line 1523, in full_dispatch_request
    rv = self.dispatch_request()
  File "c:\Users\EzraLamdin\projectRoster\.venv\lib\site-packages\flask\app.py", line 1509, in dispatch_request
    return self.ensure_sync(self.view_functions[rule.endpoint])(**req.view_args)
  File "C:\Users\EzraLamdin\projectRoster\roster.py", line 30, in about
    return render_template('about.html')
  File "c:\Users\EzraLamdin\projectRoster\.venv\lib\site-packages\flask\templating.py", line 148, in render_template
    return _render(
  File "c:\Users\EzraLamdin\projectRoster\.venv\lib\site-packages\flask\templating.py", line 128, in _render
    rv = template.render(context)
  File "c:\Users\EzraLamdin\projectRoster\.venv\lib\site-packages\jinja2\environment.py", line 1301, in render
    self.environment.handle_exception()
  File "c:\Users\EzraLamdin\projectRoster\.venv\lib\site-packages\jinja2\environment.py", line 936, in handle_exception
    raise rewrite_traceback_stack(source=source)
  File "C:\Users\EzraLamdin\projectRoster\templates\about.html", line 1, in top-level template code
    {% extends "layout.html" %}
  File "C:\Users\EzraLamdin\projectRoster\templates\layout.html", line 25, in top-level template code
    <a class="nav-link" href="{{ url_for('edit', id=user['id']) }}">Edit Account</a>
  File "c:\Users\EzraLamdin\projectRoster\.venv\lib\site-packages\jinja2\environment.py", line 466, in getitem
    return obj[argument]
jinja2.exceptions.UndefinedError: 'user' is undefined
127.0.0.1 - - [25/Jun/2022 10:06:52] "GET /?__debugger__=yes&cmd=resource&f=style.css HTTP/1.1" 304 -
127.0.0.1 - - [25/Jun/2022 10:06:52] "GET /?__debugger__=yes&cmd=resource&f=debugger.js HTTP/1.1" 304 -
127.0.0.1 - - [25/Jun/2022 10:06:52] "GET /?__debugger__=yes&cmd=resource&f=console.png HTTP/1.1" 304 -
127.0.0.1 - - [25/Jun/2022 10:06:52] "GET /?__debugger__=yes&cmd=resource&f=console.png HTTP/1.1" 304 -

在此先感謝您的幫助:)

uj5u.com熱心網友回復：

可以肯定的是，該代碼塊對用戶沒有可見性。

href="{{ url_for('edit', id=user['id']) }}"

如果您查看燒瓶教程，對于 post['username'] 之類的內容，他們使用 jinja 回圈來描述 post 所指的內容：

{% for post in posts %}
    <article class="post">
      <header>
        <div>
          <h1>{{ post['title'] }}</h1>
          <div class="about">by {{ post['username'] }} on {{ post['created'].strftime('%Y-%m-%d') }}</div>
        </div>
        {% if g.user['id'] == post['author_id'] %}
          <a class="action" href="{{ url_for('blog.update', id=post['id']) }}">Edit</a>
        {% endif %}
      </header>
      <p class="body">{{ post['body'] }}</p>
    </article>
    {% if not loop.last %}
      <hr>
    {% endif %}
  {% endfor %}

https://flask.palletsprojects.com/en/2.1.x/tutorial/blog/

所以你需要這樣的東西：

{% if g.user %}
...
{% endif %}

https://flask.palletsprojects.com/en/2.1.x/tutorial/templates/

將用戶物件傳遞給導航橫幅代碼塊。

轉載請註明出處，本文鏈接：https://www.uj5u.com/shujuku/496550.html

標籤：Python html sqlite 烧瓶神社2

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