Flask教程 - 404未找到

Question

我刚刚完成了Flask基础教程(这里),尽管我已经完成了每一步,当我尝试时

python flaskr.py

我得到的是一个404 Not Found错误的说法

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 -

什么可能出错？

Answer 1

你把你的app.run()电话太早:

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

这是在您注册任何路线之前执行的.将这两行到结束你的文件.

接下来,您的第一行show_entries()是不正确的:

def show_entries():
    db_get_db()

没有db_get_db()功能; 这应该是db = get_db().

Answer 2

我在此处遵循 Flask 应用程序设置时也发生过这种情况。在路线末尾添加尾部斜杠后，错误消失了。

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

被改为

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

问题就解决了。希望它对任何正在寻找此类问题的人有所帮助。