Question

我刚刚完成了Flask基础教程（here），即使我已经完成了每一步，当我尝试时

python flaskr.py

我得到的是404 Not Found错误说

The requested URL was not found on the server. If you entered the URL manually please check your spelling and try again.

这是文件中的代码

import os
import sqlite3
from flask import Flask, request, session, g, redirect, url_for, abort, render_template, flash

#create app
app = Flask(__name__)
app.config.from_object(__name__)

#load default conf and override config from an env var
app.config.update(dict(
    DATABASE=os.path.join(app.root_path, 'flaskr.db'),
    DEBUG=True,
    SECRET_KEY = 'dev key',
    USERNAME = 'admin',
    PASSWORD = 'admin'
))
app.config.from_envvar('FLASKR_SETTINGS', silent=True)

def connect_db():
    """connect to the specific db"""
    rv = sqlite3.connect(app.config['DATABASE'])
    rv.row_factory = sqlite3.Row
    return rv

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


def get_db():
    """opens a new db connection if there is none yet for the cyrrent app"""
    if not hasattr(g, 'sqlite_db'):
        g.sqlite_db = connect_db()
        return g.sqlite_db

@app.teardown_appcontext
def close_db(error):
    """closes the db again at the end of the request."""
if hasattr(g, 'sqlite_db'):
    g.sqlite_db.close()

def init_db():
    with app.app_context():
        db = get_db()
        with app.open_resource('schema.sql', mode='r') as f:
            db.cursor().executescript(f.read())
        db.commit()


@app.route('/')
def show_entries():
    db_get_db()
    cur = db.execute('select title, text from entries order by id desc')
    entries = cur.fetchall()
    return render_template('show_entries.html', entries=entries)

@app.route('/add', methods=['POST'])
def add_entry():
    if not session.get('logged_in'):
        abort(401)
    db = get_db()
    db.execute('insert into entries (title, text) values (?,?)',
        [request.form['title'], request.form['text']])
    db.commit()
    flash('New entry was successfully posted')
    return redirect(url_for('show_entries'))

@app.route('/login', methods=['GET', 'POST'])
def login():
    error = None
    if request.method == 'POST':
        if request.form['username'] != app.config['USERNAME']:
            error = 'Invalid username'
        elif request.form['password'] != app.config['PASSWORD']:
            error = 'Invalid password'
        else:
            session['logged_in'] = True
            flash('You were logged in')
            return redirect(url_for('show_entries'))
    return render_template('login.html', error=error)

@app.route('/logout')
def logout():
    session.pop('logged_in', None)
    flash('You were logged out')
    return redirect(url_for('show_entries'))

这是我得到的控制台消息（加上3次尝试刷新页面）：

user@user:~/Flask/flaskr$ python flaskr.py
 * Running on http://127.0.0.1:5000/
 * Restarting with reloader
127.0.0.1 - - [19/Aug/2014 15:23:40] "GET / HTTP/1.1" 404 -
127.0.0.1 - - [19/Aug/2014 15:23:41] "GET / HTTP/1.1" 404 -
127.0.0.1 - - [19/Aug/2014 15:23:42] "GET / HTTP/1.1" 404 -

有关可能出现的问题的任何建议？

Answer 1

您过早地app.run()拨打：

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

这是在您注册任何路线之前执行的。将这两行移动到文件的 end 。

接下来，show_entries()中的第一行不正确：

def show_entries():
    db_get_db()

没有db_gt_db()功能;这应该是db = get_db()。

Answer 2

在遵循Flask Application Setup here时也发生了我的事。在路径末尾添加斜杠后，错误消失了。

@app.route('/hello')
    def hello():
        return 'Hello, World!'

已更改为

@app.route('/hello/')
    def hello():
        return 'Hello, World!'

问题已解决。希望它对寻求此类问题的人有所帮助。

Flask教程 - 404未找到

2 个答案: