我是一名学习 Flask 的 Django 开发人员。我对 Flask 中的工作方式很陌生。我在访问时收到带有以下代码的 404 localhost:5000。有人可以解释为什么我得到这个：
在服务器上找不到请求的 URL。如果您手动输入了 URL，请检查您的拼写并重试。
from flask import Flask
from flask.ext.sqlalchemy import SQLAlchemy
from datetime import datetime
app = Flask(__name__)
app.config['SQLALCHEMY_DATABASE_URI'] = 'sqlite:////media/workdrive/workspace/purkinje/temp.db'
app.debug = True
db = SQLAlchemy(app)
if __name__ == '__main__':
app.run()
class Post(db.Model):
id = db.Column(db.Integer, primary_key=True)
title = db.Column(db.String(80))
body = db.Column(db.Text)
pub_date = db.Column(db.DateTime)
category_id = db.Column(db.Integer, db.ForeignKey('category.id'))
category = db.relationship('Category', backref=db.backref('posts', lazy='dynamic'))
def __init__(self, title, body, category, pub_date=None):
self.title = title
self.body = body
if pub_date is None:
pub_date = datetime.utcnow()
self.pub_date = pub_date
self.category = category
def __repr__(self):
return '<Post %r>' % self.title
class Category(db.Model):
id = db.Column(db.Integer, primary_key=True)
name = db.Column(db.String(50))
def __init__(self, name):
self.name = name
def __repr__(self):
return '<Category %r> % self.name'
@app.route('/')
def index():
posts = Post().query.all()
return render_template('templates/index.html', posts=posts)