[TOC]

路由

@app.route('/')def index():
    return '<h1>Hello World!</h1>'


def index():    
    return '<h1>Hello World!</h1>'app.add_url_rule('/', 'index', index)

# 动态路由
from flask import Flask

app = Flask(__name__)


@app.route('/')
def index():
    return '<h1>Hello World!</h1>'


@app.route('/user/<name>')
def user(name):
    return '<h1>Hello, {}!</h1>'.format(name)

# 打印出所有的路由
(venv) $ python
>>> from hello import app
>>> app.url_mapMap([<Rule '/' (HEAD, OPTIONS, GET) -> index>,
 <Rule '/static/<filename>' (HEAD, OPTIONS, GET) -> static>, 
 <Rule '/user/<name>' (HEAD, OPTIONS, GET) -> user>])

# 重定向
from flask import redirect
@app.route('/')
def index():
    return redirect('http://www.example.com')


# 抛出错误页面
from flask import abort
@app.route('/user/<id>')
def get_user(id):
    user = load_user(id)
    if not user:
        abort(404) 
    return '<h1>Hello, {}</h1>'.format(user.name)


# url_for()
url_for('.index')
"""
In its simplest usage, this function takes the view function name (or endpoint name for routes defined with app.add_url_route()) as its single argument and returns its URL. For example, in the current version of hello.py the call url_for('index') would return /, the root URL of the application. Calling url_for('index', _external=True) would instead return an absolute URL, which in this example is http://localhost:5000/.
"""

Static Files 静态文件

{% block head %}{{ super() }}
    <link rel="shortcut icon" href="{{ url_for('static', filename='favicon.ico') }}" type="image/x-icon">
    <link rel="icon" href="{{ url_for('static', filename='favicon.ico') }}" type="image/x-icon">
{% endblock %}

开发服务器

(venv) $ export FLASK_APP=hello.py
(venv) $ flask run 
* Serving Flask app "hello" 
* * Running on http://127.0.0.1:5000/ (Press CTRL+C to quit)

(venv) $ set FLASK_APP=hello.py
(venv) $ flask run * Serving Flask app "hello" 
* Running on http://127.0.0.1:5000/ (Press CTRL+C to quit)

# debug模式
(venv) $ export FLASK_APP=hello.py
(venv) $ export FLASK_DEBUG=1
(venv) $ flask run * Serving Flask app "hello" 
* Forcing debug mode on 
* Running on http://127.0.0.1:5000/ (Press CTRL+C to quit) 
* Restarting with stat 
* Debugger is active! 
* Debugger PIN: 273-181-528

# 命令行参数
(venv) $ flask run --host 0.0.0.0 
* Serving Flask app "hello" 
* Running on http://0.0.0.0:5000/ (Press CTRL+C to quit)

The Request-Response Cycle 请求响应上下文

from flask import request
@app.route('/')
def index():    
    user_agent = request.headers.get('User-Agent')
    return '<p>Your browser is {}</p>'.format(user_agent)

post

from flask import request

@app.route('/login', methods=['POST', 'GET'])
def login():
    error = None
    if request.method == 'POST':
        if valid_login(request.form['username'],
                       request.form['password']):
            return log_the_user_in(request.form['username'])
        else:
            error = 'Invalid username/password'
    # the code below is executed if the request method
    # was GET or the credentials were invalid
    return render_template('login.html', error=error)

print request.form.get('myid')    #input
print request.form.getlist('mychecks')    #check组

全局变量

current_app
g
request
session

>>> from hello import app
>>> from flask import current_app
>>> current_app.name
Traceback (most recent call last):
...RuntimeError:
 working outside of application context
>>> app_ctx = app.app_context()
>>> app_ctx.push()
>>> current_app.name
'hello'
>>> app_ctx.pop()

The Request Object

http://flask.pocoo.org/docs/0.12/api/#incoming-request-data

form dict对象
args dict对象
values dict对象
cookies dict对象

Request Hooks 请求钩子

before_first_request

before_request

@auth.before_app_request
def before_request():
    if current_user.is_authenticated:
        current_user.ping()
        if not current_user.confirmed \
                and request.endpoint \
                and request.blueprint != 'auth' \
                and request.endpoint != 'static':
            return redirect(url_for('auth.unconfirmed'))

after_request
teardown_request

Responses 响应对象

http://flask.pocoo.org/docs/0.12/api/#response-objects

from flask import make_response
@app.route('/')
def index():
    response = make_response('<h1>This document carries a cookie!</h1>')
    response.set_cookie('answer', '42')
    return response

headers

A Headers object representing the response headers.

status

A string with a response status.

status_code

The response status as integer.

data

A descriptor that calls get_data() and set_data(). This should not be used and will eventually get deprecated.

mimetype

The mimetype (content type without charset etc.)

Templates

# 模板渲染
from flask import Flask, render_template
# ...
@app.route('/')
def index():
    return render_template('index.html')


@app.route('/user/<name>')
def user(name):    
    return render_template('user.html', name=name)

jinjia2 内置过滤器

Hello,

safe
capitalize
lower
upper
title
trim
striptags

渲染语法

{% macro render_comment(comment) %}
    <li>{{ comment }}</li>
{% endmacro %}

<ul>
    {% for comment in comments %}
        {{ render_comment(comment) }}
    {% endfor %}
</ul>

<!-- example 2 部分渲染 -->
{% import 'macros.html' as macros %}
<ul>
    {% for comment in comments %}
        {{ macros.render_comment(comment) }}
    {% endfor %}
</ul>




<!-- example 块语法 -->
<html>
<head>
    {% block head %}
        <title>{% block title %}{% endblock %} - My Application</title>
    {% endblock %}
</head>
<body>
{% block body %}{% endblock %}
</body>
</html>





<!-- example 使用super()保留原来的内容 -->
{% extends "base.html" %}
{% block title %}Index{% endblock %}
{% block head %}   {{ super() }}    <style>    </style>{% endblock %}
{% block body %}<h1>Hello, World!</h1>{% endblock %}

集成bootstrap

(venv) $ pip install flask-bootstrap

from flask_bootstrap import Bootstrap
# ...
bootstrap = Bootstrap(app)

导航菜单示例

{% extends "bootstrap/base.html" %}
{% block title %}页面标题{% endblock %}
{% block navbar %}
    <div class="navbar navbar-inverse" role="navigation">
        <div class="container">
            <div class="navbar-header">
                <button type="button" class="navbar-toggle" data-toggle="collapse" data-target=".navbar-collapse">
                    <span class="sr-only">Toggle navigation</span>
                    <span class="icon-bar"></span>
                    <span class="icon-bar"></span>
                    <span class="icon-bar"></span>
                </button>
                <a class="navbar-brand" href="/">Flasky</a>
            </div>
            <div class="navbar-collapse collapse">
                <ul class="nav navbar-nav">
                    <li><a href="/">Home</a></li>
                </ul>
            </div>
        </div>
    </div>
{% endblock %}

{% block content %}
    <div class="container">
        <div class="page-header">
            <h1>Hello, {{ name }}!</h1>
        </div>
    </div>
{% endblock %}

错误页面

@app.errorhandler(404)
def page_not_found(e):
    return render_template('404.html'), 404
    
@app.errorhandler(500)
def internal_server_error(e):
    return render_template('500.html'), 500

表单

(venv) $ pip install flask-wtf

from flask_wtf import FlaskForm
from wtforms import StringField, SubmitField
from wtforms.validators import DataRequired

class NameForm(FlaskForm):
    name = StringField('What is your name?', validators=[DataRequired()])
    submit = SubmitField('Submit')

@app.route('/', methods=['GET', 'POST'])
def index():
    name = None
    form = NameForm()
    if form.validate_on_submit():
        name = form.name.data
        form.name.data = ''    
    return render_template('index.html', form=form, name=name)

session

from flask import Flask, render_template, session, redirect, url_for
@app.route('/', methods=['GET', 'POST'])
def index():
    form = NameForm()
    if form.validate_on_submit():
        session['name'] = form.name.data
        return redirect(url_for('index'))
    return render_template('index.html', form=form, name=session.get('name'))

database

(venv) $ pip install flask-sqlalchemy

http://flask-sqlalchemy.pocoo.org/2.3/config/

关联表

class Role(db.Model):
    # ...    
    users = db.relationship('User', backref='role')
    
class User(db.Model):    
    # ...    
    role_id = db.Column(db.Integer, db.ForeignKey('roles.id'))

(venv) $ flask shell
>>> from hello import db>
>> db.create_all()

多表关联


registrations = db.Table('registrations',
                         db.Column('student_id', db.Integer, db.ForeignKey('students.id')),
                         db.Column('class_id', db.Integer, db.ForeignKey('classes.id')))


class Student(db.Model):
    id = db.Column(db.Integer, primary_key=True)
    name = db.Column(db.String)
    classes = db.relationship('Class', secondary=registrations,
                              backref=db.backref('students', lazy='dynamic'),
                              lazy='dynamic')


class Class(db.Model):
    id = db.Column(db.Integer, primary_key=True)
    name = db.Column(db.String)

操作

>>> s.classes.append(c)
>>> db.session.add(s)

>>> s.classes.all()
>>> c.students.all()

>>> s.classes.remove(c)

example

view

@app.route('/', methods=['GET', 'POST'])
def index():
    form = NameForm()
    if form.validate_on_submit():
        user = User.query.filter_by(username=form.name.data).first()
        if user is None:
            user = User(username=form.name.data)
            db.session.add(user)
            db.session.commit()
            session['known'] = False
        else:
            session['known'] = True
        session['name'] = form.name.data
        form.name.data = ''
        return redirect(url_for('index'))
    return render_template('index.html',
                           form=form, name=session.get('name'),
                           known=session.get('known', False))

html

{% extends "base.html" %}{% import "bootstrap/wtf.html" as wtf %}
{% block title %}Flasky{% endblock %}
{% block page_content %}
    <div class="page-header">
        <h1>Hello, {% if name %}{{ name }}{% else %}Stranger{% endif %}!</h1>
        {% if not known %}
            <p>Pleased to meet you!</p>
        {% else %}
            <p>Happy to see you again!</p>
        {% endif %}
    </div>
    {{ wtf.quick_form(form) }}
{% endblock %}

## 集成到shell命令行中

@app.shell_context_processor
def make_shell_context():
    return dict(db=db, User=User, Role=Role)

$ flask shell
>>> app
<Flask 'hello'>
>>> db
<SQLAlchemy engine='sqlite:////home/flask/flasky/data.sqlite'>
>>> User
<class 'hello.User'>

迁移文件

(venv) $ pip install flask-migrate

from flask_migrate import Migrate

# ...

migrate = Migrate(app, db)

(venv) $ flask db init  
Creating directory /home/flask/flasky/migrations...done  
Creating directory /home/flask/flasky/migrations/versions...done

迁移文件

# 加上注释便于回滚
(venv) $ flask db migrate -m "initial migration"
INFO  [alembic.migration] Context impl SQLiteImpl.
  Generating /home/flask/flasky/migrations/versions/1bc  594146bb5_initial_migration.py...done

(venv) $ flask db upgrade
INFO  [alembic.migration] Context impl SQLiteImpl.
INFO  [alembic.migration] Will assume non-transactional DDL.
INFO  [alembic.migration] Running upgrade None -> 1bc594146bb5, initial migration

邮件

(venv) $ pip install flask-mail

import os
# ...
app.config['MAIL_SERVER'] = 'smtp.googlemail.com'
app.config['MAIL_PORT'] = 587
app.config['MAIL_USE_TLS'] = True
app.config['MAIL_USERNAME'] = os.environ.get('MAIL_USERNAME')
app.config['MAIL_PASSWORD'] = os.environ.get('MAIL_PASSWORD')

from flask_mail import Mail
mail = Mail(app)

(venv) $ export MAIL_USERNAME=<Gmail username>
(venv) $ export MAIL_PASSWORD=<Gmail password>

# windows 
(venv) $ set MAIL_USERNAME=<Gmail username>
(venv) $ set MAIL_PASSWORD=<Gmail password>

shell 命令行中发送邮件

(venv) $ flask shell
>>> from flask_mail import Message
>>> from hello import mail
>>> msg = Message('test email', sender='you@example.com',
...     recipients=['you@example.com'])
>>> msg.body = 'This is the plain text body'
>>> msg.html = 'This is the <b>HTML</b> body'
>>> with app.app_context():
...    mail.send(msg)
...

Integrating Emails with the Application 集成到应用中

from flask_mail import Message
app.config['FLASKY_MAIL_SUBJECT_PREFIX'] = '[Flasky]'
app.config['FLASKY_MAIL_SENDER'] = 'Flasky Admin <flasky@example.com>'

def send_email(to, subject, template, **kwargs):
    msg = Message(app.config['FLASKY_MAIL_SUBJECT_PREFIX'] + subject,
                  sender=app.config['FLASKY_MAIL_SENDER'], recipients=[to])    
    msg.body = render_template(template + '.txt', **kwargs)    
    msg.html = render_template(template + '.html', **kwargs)    mail.send(msg)

example


# ...
app.config['FLASKY_ADMIN'] = os.environ.get('FLASKY_ADMIN')
# ...
@app.route('/', methods=['GET', 'POST'])
def index():
    form = NameForm()
    if form.validate_on_submit():
        user = User.query.filter_by(username=form.name.data).first()
        if user is None:
            user = User(username=form.name.data)
            db.session.add(user)  
            session['known'] = False
            if app.config['FLASKY_ADMIN']:
                send_email(app.config['FLASKY_ADMIN'], 'New User',
                           'mail/new_user', user=user)        
        else:
            session['known'] = True
        session['name'] = form.name.data
        form.name.data = ''
        return redirect(url_for('index'))    
     return render_template('index.html',
                            form=form, name=session.get('name'), 
                            known=session.get('known', False))

(venv) $ export FLASKY_ADMIN=<your-email-address>

(venv) $ set FLASKY_ADMIN=<your-email-address>

Sending Asynchronous Email

from threading import Thread


def send_async_email(app, msg):
    with app.app_context():
        mail.send(msg)


def send_email(to, subject, template, **kwargs):
    msg = Message(
        app.config['FLASKY_MAIL_SUBJECT_PREFIX'] + subject,
        sender=app.config['FLASKY_MAIL_SENDER'],
        recipients=[to]
    )
    msg.body = render_template(template + '.txt', **kwargs)
    msg.html = render_template(template + '.html', **kwargs)
    thr = Thread(target=send_async_email, args=[app, msg])
    thr.start()
    return thr

大型项目文件结构

flasky
├── LICENSE
├── README.md
├── __pycache__
│   └── hello.cpython-35.pyc
├── app
│   ├── __init__.py
│   ├── email.py
│   ├── main
│   │   ├── __init__.py
│   │   ├── errors.py
│   │   ├── forms.py
│   │   └── views.py
│   ├── models.py
│   ├── static
│   │   └── favicon.ico
│   └── templates
│       ├── 404.html
│       ├── 500.html
│       ├── base.html
│       ├── index.html
│       └── mail
│           ├── new_user.html
│           └── new_user.txt
├── config.py
├── flasky.py
├── migrations
│   ├── README
│   ├── alembic.ini
│   ├── env.py
│   ├── script.py.mako
│   └── versions
│       └── 38c4e85512a9_initial_migration.py
├── requirements.txt
└── tests
    ├── __init__.py
    └── test_basics.py

9 directories, 27 files

config.py

import os
basedir = os.path.abspath(os.path.dirname(__file__))


class Config:
    SECRET_KEY = os.environ.get('SECRET_KEY') or 'hard to guess string'
    MAIL_SERVER = os.environ.get('MAIL_SERVER', 'smtp.googlemail.com')
    MAIL_PORT = int(os.environ.get('MAIL_PORT', '587'))
    MAIL_USE_TLS = os.environ.get('MAIL_USE_TLS', 'true').lower() in \
        ['true', 'on', '1']
    MAIL_USERNAME = os.environ.get('MAIL_USERNAME')
    MAIL_PASSWORD = os.environ.get('MAIL_PASSWORD')
    FLASKY_MAIL_SUBJECT_PREFIX = '[Flasky]'
    FLASKY_MAIL_SENDER = 'Flasky Admin <flasky@example.com>'
    FLASKY_ADMIN = os.environ.get('FLASKY_ADMIN')
    SQLALCHEMY_TRACK_MODIFICATIONS = False

    @staticmethod
    def init_app(app):
        pass


class DevelopmentConfig(Config):
    DEBUG = True
    SQLALCHEMY_DATABASE_URI = os.environ.get('DEV_DATABASE_URL') or \
        'sqlite:///' + os.path.join(basedir, 'data-dev.sqlite')


class TestingConfig(Config):
    TESTING = True
    SQLALCHEMY_DATABASE_URI = os.environ.get('TEST_DATABASE_URL') or \
        'sqlite://'


class ProductionConfig(Config):
    SQLALCHEMY_DATABASE_URI = os.environ.get('DATABASE_URL') or \
        'sqlite:///' + os.path.join(basedir, 'data.sqlite')


config = {
    'development': DevelopmentConfig,
    'testing': TestingConfig,
    'production': ProductionConfig,

    'default': DevelopmentConfig
}

app/main/init.py: Blueprint creation 蓝图创建

from flask import Blueprint

main = Blueprint('main', __name__)

from . import views, errors

app/init.py

from flask import Flask
from flask_bootstrap import Bootstrap
from flask_mail import Mail
from flask_moment import Moment
from flask_sqlalchemy import SQLAlchemy
from config import config

bootstrap = Bootstrap()
mail = Mail()
moment = Moment()
db = SQLAlchemy()


def create_app(config_name):
    app = Flask(__name__)
    app.config.from_object(config[config_name])
    config[config_name].init_app(app)

    bootstrap.init_app(app)
    mail.init_app(app)
    moment.init_app(app)
    db.init_app(app)

    from .main import main as main_blueprint # 注册蓝图
    app.register_blueprint(main_blueprint) # 注册蓝图

    return app

app/main/errors.py: Blueprint with error handlers

from flask import render_template
from . import main


@main.app_errorhandler(404)
def page_not_found(e):
    return render_template('404.html'), 404


@main.app_errorhandler(500)
def internal_server_error(e):
    return render_template('500.html'), 500

app/main/views.py: Blueprint with application routes

from flask import render_template, session, redirect, url_for, current_app
from .. import db
from ..models import User
from ..email import send_email
from . import main
from .forms import NameForm


@main.route('/', methods=['GET', 'POST'])
def index():
    form = NameForm()
    if form.validate_on_submit():
        user = User.query.filter_by(username=form.name.data).first()
        if user is None:
            user = User(username=form.name.data)
            db.session.add(user)
            session['known'] = False
            if current_app.config['FLASKY_ADMIN']:
                send_email(current_app.config['FLASKY_ADMIN'], 'New User',
                           'mail/new_user', user=user)
        else:
            session['known'] = True
        session['name'] = form.name.data
        return redirect(url_for('.index'))
    return render_template('index.html',
                           form=form, name=session.get('name'),
                           known=session.get('known', False))

Application Script

flasky.py: Main script

import os
from flask_migrate import Migrate
from app import create_app, db
from app.models import User, Role

app = create_app(os.getenv('FLASK_CONFIG') or 'default')
migrate = Migrate(app, db)


@app.shell_context_processor
def make_shell_context():
    return dict(db=db, User=User, Role=Role)


@app.cli.command()
def test():
    """Run the unit tests."""
    import unittest
    tests = unittest.TestLoader().discover('tests')
    unittest.TextTestRunner(verbosity=2).run(tests)

Requirements File

(venv) $ pip freeze >requirements.txt 

(venv) $ pip install -r requirements.txt  # 安装

Unit Tests

tests/test_basics.py: Unit tests

import unittest
from flask import current_app
from app import create_app, db


class BasicsTestCase(unittest.TestCase):
    def setUp(self):
        self.app = create_app('testing')
        self.app_context = self.app.app_context()
        self.app_context.push()
        db.create_all()

    def tearDown(self):
        db.session.remove()
        db.drop_all()
        self.app_context.pop()

    def test_app_exists(self):
        self.assertFalse(current_app is None)

    def test_app_is_testing(self):
        self.assertTrue(current_app.config['TESTING'])

flasky.py: Unit test launcher command

@app.cli.command()
def test():
    """Run the unit tests."""
    import unittest
    tests = unittest.TestLoader().discover('tests')
    unittest.TextTestRunner(verbosity=2).run(tests)

运行单元测试

(venv) $ flask test
test_app_exists (test_basics.BasicsTestCase) ... ok
test_app_is_testing (test_basics.BasicsTestCase) ... ok
.----------------------------------------------------------------------
Ran 2 tests in 0.001s

OK

修改模型

(venv) $  flask db upgrade
INFO  [alembic.runtime.migration] Context impl SQLiteImpl.
INFO  [alembic.runtime.migration] Will assume non-transactional DDL.
INFO  [alembic.runtime.migration] Running upgrade  -> 38c4e85512a9, initial migration

Running the Application

(venv) $ export FLASK_APP=flasky.py
(venv) $ export FLASK_DEBUG=1
(venv) $ flask run

utils

获取当前时间

Message Flashing 消息闪现

from flask import Flask, render_template, session, redirect, url_for, flash
@app.route('/', methods=['GET', 'POST'])
def index():
    form = NameForm()
    if form.validate_on_submit():
        old_name = session.get('name')
        if old_name is not None and old_name != form.name.data:
            flash('Looks like you have changed your name!')
        session['name'] = form.name.data
        return redirect(url_for('index'))    
    return render_template('index.html',  form = form, name = session.get('name'))

{% block content %}
    <div class="container">
        {% for message in get_flashed_messages() %}
            <div class="alert alert-warning">
                <button type="button" class="close" data-dismiss="alert">&times;</button>
                {{ message }}
            </div>
        {% endfor %}
        {% block page_content %}{% endblock %}
    </div>
{% endblock %}

flask使用总结1

路由