flaskr 报错及其修改

作者：hhh5460

官网有一个flaskr的例子，按照其8个步骤（包括测试），一步一步照着做，有3个地方报错。

究其原因，可能是flaskr这个例子年代比较久远，而现在python以及flask都有了很大的变动。

我的环境：win7(64) + python 3.5(64)

这里只直接贴出修改后的代码（出错的地方被注释了）。

其中flaskr.py有2处报错：

# flaskr.py

# 所有的导入
import sqlite3
from flask import Flask, request, session, g, redirect, url_for, \
     abort, render_template, flash

# 配置
# DATABASE = '/tmp/flaskr.db' # 报错1: sqlite3.OperationalError: unable to open database file
import os
PROJECT_ROOT = os.path.dirname(os.path.realpath(__file__))
DATABASE = os.path.join(PROJECT_ROOT, 'tmp', 'flaskr.db') # 改正1：不把路径写死
DEBUG = True
SECRET_KEY = 'development key'
USERNAME = 'admin'
PASSWORD = 'default'

# 创建我们的小程序
app = Flask(__name__)
app.config.from_object(__name__) # from_object() 将会寻找给定的对象(如果它是一个字符串，则会导入它)，
                                 # 搜寻里面定义的全部大写的变量。

def connect_db():
    return sqlite3.connect(app.config['DATABASE'])

from contextlib import closing
def init_db():
    with closing(connect_db()) as db:
        with app.open_resource('schema.sql') as f:
            #db.cursor().executescript(f.read()) # 报错2: ValueError: script argument must be unicode
            db.cursor().executescript(f.read().decode()) # 改正2：加了decode()
        db.commit()

@app.before_request
def before_request():
    g.db = connect_db()

@app.teardown_request
def teardown_request(exception):
    g.db.close()

#四个视图函数：
# 1.显示条目
@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)

# 2.添加新条目
@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'))

# 3.登录
@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)

# 4.注销
@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()

另，测试文件flaskr_test.py有1处报错：

import os
import flaskr
import unittest
import tempfile

class FlaskrTestCase(unittest.TestCase):

    def setUp(self):
        self.db_fd, flaskr.app.config['DATABASE'] = tempfile.mkstemp()
        flaskr.app.config['TESTING'] = True
        self.app = flaskr.app.test_client()
        flaskr.init_db()

    def tearDown(self):
        os.close(self.db_fd)
        os.unlink(flaskr.app.config['DATABASE'])

    # 测试1：访问应用程序的根目录(/)
    def test_empty_db(self):
        rv = self.app.get('/')
        #assert 'No entries here so far' in rv.data # 报错3：TypeError: a bytes-like object is required, not 'str'
        assert b'No entries here so far' in rv.data # 改正3：文字修改为byte类型（或者rv.data修改为rv.data.decode()），以下都要同样修改！！

    def login(self, username, password):
        return self.app.post('/login', data=dict(username=username, password=password), follow_redirects=True)

    def logout(self):
        return self.app.get('/logout', follow_redirects=True)

    # 测试2：登录和注销
    def test_login_logout(self):
        rv = self.login('admin', 'default')
        assert b'You were logged in' in rv.data
        rv = self.logout()
        assert b'You were logged out' in rv.data
        rv = self.login('adminx', 'default')
        assert b'Invalid username' in rv.data
        rv = self.login('admin', 'defaultx')
        assert b'Invalid password' in rv.data

    # 测试3：添加新条目
    def test_messages(self):
        self.login('admin', 'default')
        rv = self.app.post('/add', data=dict(title='<Hello>', text='<strong>HTML</strong> allowed here'), follow_redirects=True)
        assert b'No entries here so far' not in rv.data
        assert b'&lt;Hello&gt;' in rv.data
        assert b'<strong>HTML</strong> allowed here' in rv.data

if __name__ == '__main__':
    unittest.main()

效果图