flaskr 是一个功能简单的博客程序，是 flask 官方实例。
这个实例能找到三个版本的教程——一个英文版和两个中文翻译版。三个版本内容都不尽相同，而且对新手都不友好。其中一个中文版还有遗漏，无法运行。
下面是一套能运行的代码。
文件结构
/flaskr
/flaskr.py
/schema.sql
/static
/style.css
/templates
/layout.html
/login.html
/show_entries.html
/import_initdb.py # 这项是我自己创建的
代码
flaskr.py
import sqlite3
from flask import (Flask, request, session, g, redirect, url_for,
abort, render_template, flash)
from contextlib import closing
# 配置
DATABASE = '/tmp/flaskr.db'
DEBUG = True
SECRET_KEY = 'development key'
USERNAME = 'admin'
PASSWORD = 'default'
app = Flask(__name__)
app.config.from_object(__name__)
def connect_db():
return sqlite3.connect(app.config['DATABASE'])
def init_db():
with closing(connect_db()) as db:
with app.open_resource('schema.sql', mode='r') as f:
db.cursor().executescript(f.read())
db.commit()
@app.before_request
def before_request():
g.db = connect_db()
@app.teardown_request
def teardown_request(exception):
db = getattr(g, 'db', None)
if db is not None:
db.close()
@app.route('/')
def show_entries():
cur = g.db.execute('select title, text from entries order by id desc')
entries = [dict(title=row[0], text=row[1]) for row in 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)
g.db.execute('insert into entries (title, text) values (?, ?)',
[request.form['title'], request.form['text']])
g.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'))
if __name__ == '__main__':
app.run()
schema.sql
drop table if exists entries;
create table entries (
id integer primary key autoincrement,
title text not null,
text text not null
);
style.css
body { font-family: sans-serif; background: #eee; }
a, h1, h2 { color: #377ba8; }
h1, h2 { font-family: 'Georgia', serif; margin: 0; }
h1 { border-bottom: 2px solid #eee; }
h2 { font-size: 1.2em; }
.page { margin: 2em auto; width: 35em; border: 5px solid #ccc;
padding: 0.8em; background: white; }
.entries { list-style: none; margin: 0; padding: 0; }
.entries li { margin: 0.8em 1.2em; }
.entries li h2 { margin-left: -1em; }
.add-entry { font-size: 0.9em; border-bottom: 1px solid #ccc; }
.add-entry dl { font-weight: bold; }
.metanav { text-align: right; font-size: 0.8em; padding: 0.3em;
margin-bottom: 1em; background: #fafafa; }
.flash { background: #cee5F5; padding: 0.5em;
border: 1px solid #aacbe2; }
.error { background: #f0d6d6; padding: 0.5em; }
layout.html
<!doctype html>
<title>Flaskr</title>
<link rel=stylesheet type=text/css href="{{ url_for('static', filename='style.css') }}">
<div class=page>
<h1>Flaskr</h1>
<div class=metanav>
{% if not session.logged_in %}
<a href="{{ url_for('login') }}">log in</a>
{% else %}
<a href="{{ url_for('logout') }}">log out</a>
{% endif %}
</div>
{% for message in get_flashed_messages() %}
<div class=flash>{{ message }}</div>
{% endfor %}
{% block body %}{% endblock %}
</div>
login.html
{% extends "layout.html" %}
{% block body %}
<h2>Login</h2>
{% if error %}<p class=error><strong>Error:</strong> {{ error }}{% endif %}
<form action="{{ url_for('login') }}" method=post>
<dl>
<dt>Username:
<dd><input type=text name=username>
<dt>Password:
<dd><input type=password name=password>
<dd><input type=submit value=Login>
</dl>
</form>
{% endblock %}
show_entries.html
{% extends "layout.html" %}
{% block body %}
{% if session.logged_in %}
<form action="{{ url_for('add_entry') }}" method=post class=add-entry>
<dl>
<dt>Title:
<dd><input type=text size=30 name=title>
<dt>Text:
<dd><textarea name=text rows=5 cols=40></textarea>
<dd><input type=submit value=Share>
</dl>
</form>
{% endif %}
<ul class=entries>
{% for entry in entries %}
<li><h2>{{ entry.title }}</h2>{{ entry.text|safe }}
{% else %}
<li><em>Unbelievable. No entries here so far</em>
{% endfor %}
</ul>
{% endblock %}
import_initdb.py
from flaskr import init_db
init_db()
试用
先运行 import_initdb.py 再运行 flaskr.py
在浏览器地址栏输入http://127.0.0.1:5000/
点击右上角登陆，用户名是admin ，密码是default
中文翻译版教程（无遗漏那版）
20180117
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