flask 扩展

flask信号（源码）

  • 信号
    信号，是在flask框架中为我们预留的钩子，让我们可以进行一些自定义操作。
pip3 install blinker

根据flask项目的请求流程来进行设置扩展点

  • 中间件

    from flask import Flask,render_template

app = Flask(__name__)


@app.route('/index')
def index():
    return render_template('index.html')


@app.route('/order')
def order():
    return render_template('order.html')


class MyMiddleware(object):
    def __init__(self,old_app):
        self.wsgi_app = old_app.wsgi_app

    def __call__(self, *args, **kwargs):
        print('123')
        result = self.wsgi_app(*args, **kwargs)
        print('456')
        return result

app.wsgi_app = MyMiddleware(app)

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

  • 当app_ctx被push到local中栈之后，会触发appcontext_pushed信号，之前注册在这个信号中的方法，就会被执行。

    from flask import Flask,render_template
from flask import signals

app = Flask(__name__)

@signals.appcontext_pushed.connect
def f1(arg):
    print('appcontext_pushed信号f1被触发',arg)

@signals.appcontext_pushed.connect
def f2(arg):
    print('appcontext_pushed信号f2被触发',arg)

@app.route('/index')
def index():
    return render_template('index.html')

@app.route('/order')
def order():
    return render_template('order.html')

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

  • 执行before_first_request扩展

    from flask import Flask,render_template

app = Flask(__name__)

@app.before_first_request
def f2():
    print('before_first_requestf2被触发')

@app.route('/index')
def index():
    return render_template('index.html')

@app.route('/order')
def order():
    return render_template('order.html')

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

  • request_started信号

    from flask import Flask,render_template
from flask import signals
app = Flask(__name__)

@signals.request_started.connect
def f3(arg):
    print('request_started信号被触发',arg)

@app.route('/index')
def index():
    return render_template('index.html')

@app.route('/order')
def order():
    return render_template('order.html')

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

  • url_value_processor

    from flask import Flask,render_template,g
from flask import signals
app = Flask(__name__)


@app.url_value_preprocessor
def f5(endpoint,args):
    print('f5')

@app.route('/index/')
def index():
    print('index')
    return render_template('index.html')

@app.route('/order')
def order():
    print('order')
    return render_template('order.html')

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

  • before_reuqest

    from flask import Flask,render_template,g
from flask import signals
app = Flask(__name__)

@app.before_request
def f6():
    g.xx = 123
    print('f6')

@app.route('/index/')
def index():
    print('index')
    return render_template('index.html')

@app.route('/order')
def order():
    print('order')
    return render_template('order.html')

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

  • before_render_template / rendered_template

    from flask import Flask,render_template,g
from flask import signals
app = Flask(__name__)

@signals.before_render_template.connect
def f7(app, template, context):
    print('f7')

@signals.template_rendered.connect
def f8(app, template, context):
    print('f8')

@app.route('/index/')
def index():
    return render_template('index.html')

@app.route('/order')
def order():
    print('order')
    return render_template('order.html')

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

  • after_request

    from flask import Flask,render_template,g
from flask import signals
app = Flask(__name__)

@app.after_request
def f9(response):
    print('f9')
    return response

@app.route('/index/')
def index():
    return render_template('index.html')

@app.route('/order')
def order():
    print('order')
    return render_template('order.html')

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

  • request_finished

    from flask import Flask,render_template,g
from flask import signals
app = Flask(__name__)

@signals.request_finished.connect
def f10(app,response):
    print('f10')

@app.route('/index/')
def index():
    return render_template('index.html')

@app.route('/order')
def order():
    print('order')
    return render_template('order.html')

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

  • got_request_exception

    from flask import Flask,render_template,g
from flask import signals
app = Flask(__name__)

@app.before_first_request
def test():
    int('asdf')

@signals.got_request_exception.connect
def f11(app,exception):
    print('f11')

@app.route('/index/')
def index():
    return render_template('index.html')

@app.route('/order')
def order():
    print('order')
    return render_template('order.html')

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

  • teardown_request

    from flask import Flask,render_template,g
from flask import signals
app = Flask(__name__)

@app.teardown_request
def f12(exc):
    print('f12')

@app.route('/index/')
def index():
    return render_template('index.html')

@app.route('/order')
def order():
    print('order')
    return render_template('order.html')

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

  • request_tearing_down

from flask import Flask,render_template,g
from flask import signals
app = Flask(__name__)

@signals.request_tearing_down.connect
def f13(app,exc):
    print('f13')

@app.route('/index/')
def index():
    return render_template('index.html')

@app.route('/order')
def order():
    print('order')
    return render_template('order.html')

if __name__ == '__main__':
    app.run()
  • appcontext_popped
from flask import Flask,render_template,g
from flask import signals
app = Flask(__name__)

@signals.appcontext_popped.connect
def f14(app):
    print('f14')

@app.route('/index/')
def index():
    return render_template('index.html')

@app.route('/order')
def order():
    print('order')
    return render_template('order.html')

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

总结：关于flask内部共有14+个扩展点用于我们对flask框架内部进行定制，其中有：9个是信号。

template_rendered = _signals.signal("template-rendered")
before_render_template = _signals.signal("before-render-template")
request_started = _signals.signal("request-started")
request_finished = _signals.signal("request-finished")
request_tearing_down = _signals.signal("request-tearing-down")
got_request_exception = _signals.signal("got-request-exception")
appcontext_tearing_down = _signals.signal("appcontext-tearing-down")
appcontext_pushed = _signals.signal("appcontext-pushed")
appcontext_popped = _signals.signal("appcontext-popped")

message_flashed = _signals.signal("message-flashed")

扩展:flash

flash存值之后只能取一次

from flask import Flask,render_template,flash,get_flashed_messages,session
from flask import signals
app = Flask(__name__)
app.secret_key = 'iuknsoiuwknlskjdf'

@app.route('/index/')
def index():
    # flash('123')
    session['k1'] = 123
    return render_template('index.html')

@app.route('/order')
def order():
    # messages = get_flashed_messages()
    # print(messages)
    val = session['k1']
    del session['k1']
    print(val)
    return render_template('order.html')

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

2.flask-script

flask的组件，用于运行flask程序。

  • 安装

    pip3 install flask-script

  • 使用
    1574752970224

  • 其他执行命令

    from s24day95 import create_app
from flask_script import Manager

app = create_app()
manager = Manager(app)

@manager.command
def custom(arg):
    """
    自定义命令
    python manage.py custom 123
    :param arg:
    :return:
    """
    print(arg)

@manager.option('-n', '--name', dest='name')
@manager.option('-u', '--url', dest='url')
def cmd(name, url):
    """
    自定义命令
    执行： python manage.py  cmd -n wupeiqi -u http://www.oldboyedu.com
    :param name:
    :param url:
    :return:
    """
    print(name, url)

if __name__ == '__main__':
    manager.run()
posted @ 2019-12-03 09:26  阿浪阿浪  阅读(189)  评论(0)  编辑  收藏  举报