Python的Flask开发框架简单上手笔记

#!/usr/bin/env python
# encoding: utf-8

from flask import Flask
app = Flask(__name__)

@app.route('/')
def index():
  return 'hello world'

if __name__ == '__main__':
  app.run(debug=True)
  #app.run(host='127.0.0.1',port=8000)

@app.route('/',methods=['GET','POST'])

@app.route('/')
@app.route('/index')

from flask import request
args = request.args if request.method == 'GET' else request.form
a = args.get('a','default')

"Content-Type": "application/json"

data = request.get_json(silent=False)

{%for page in pages %}
<tr><td><input type=checkbox name=do_delete value="{{ page['id'] }}"></td><td>
{%endfor%}

page_ids = request.form.getlist("do_delete")

@app.route('/query/<qid>/')
def query(qid):
  pass

from flask import g

app = .....

@app.before_request
def before_request():
  g.session = create_session()

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

@app.template_filter('reverse')
def reverse_filter(s):
  return s[::-1]

def reverse_filter(s):
  return s[::-1]
app.jinja_env.filters['reverse'] = reverse_filter

def a():...
def b():...

FIL = {'a': a,'b':b}
app.jinja_env.filters.update(FIL)

JINJA2_GLOBALS = {'MEDIA_PREFIX': '/media/'}
app.jinja_env.globals.update(JINJA2_GLOBALS)

app = Flask(__name__,template_folder=settings.TEMPLATE_FOLDER,static_folder = settings.STATIC_PATH)

from flask import Blueprint
bp_test = Blueprint('test',__name__)
#bp_test = Blueprint('test',__name__,url_prefix='/abc')

@bp_test.route('/')

--------
from xxx import bp_test

app = Flask(__name__)
app.register_blueprint(bp_test)

bp_video = Blueprint('video',url_prefix='/kw_news/video')
@bp_video.route('/search/category/',methods=['POST','GET'])
#注意这种情况下Blueprint中url_prefix不能以 '/' 结尾,否则404

app.secret_key = 'PS#yio`%_!((f_or(%)))s'

from flask import session

session['somekey'] = 1
session.pop('logged_in',None)

session.clear()

#过期时间,通过cookie实现的
from datetime import timedelta
session.permanent = True
app.permanent_session_lifetime = timedelta(minutes=5)

from flask import url_for,render_template

@app.route("/")
def home():
  login_uri = url_for("login",next=url_for("home"))
  return render_template("home.html",**locals())

<form action="/image/upload/" method="post" enctype="multipart/form-data">
<input type="file" name="upload" />

f = request.files.get('upload')
img_data = f.read()

return send_file(settings.TEMPLATE_FOLDER + 'tweet/tweet_list.html')

flask.redirect(location,code=302) the redirect status code. defaults to 302.Supported codes are 301,302,303,305,and 307. 300 is not supported.

@app.route('/')
def hello():
  return redirect(url_for('foo'))

@app.route('/foo')
def foo():
  return'Hello Foo!'

from werkzeug.contrib.fixers import ProxyFix
app.wsgi_app = ProxyFix(app.wsgi_app)
return json & jsonp
import json
from flask import jsonify,Response,json

data = [] # or others
return jsonify(ok=True,data=data)

jsonp_callback = request.args.get('callback','')
if jsonp_callback:
  return Response(
      "%s(%s);" % (jsonp_callback,json.dumps({'ok': True,'data':data})),mimetype="text/javascript"
      )
return ok_jsonify(data)

# create our little application :)
app = Flask(__name__)

# Load default config and override config from an environment variable
app.config.update(dict(
  DATABASE='/tmp/flaskr.db',DEBUG=True,SECRET_KEY='development key',USERNAME='admin',PASSWORD='default'
))
app.config.from_envvar('FLASKR_SETTINGS',silent=True)


------------------
# configuration
DATABASE = '/tmp/minitwit.db'
PER_PAGE = 30
DEBUG = True
SECRET_KEY = 'development key'

# create our little application :)
app = Flask(__name__)
app.config.from_object(__name__)
app.config.from_envvar('MINITWIT_SETTINGS',silent=True)

from flask import abort,flash

abort
if not session.get('logged_in'):
  abort(401)

flash
flash('New entry was successfully posted')

from threading import Thread

def async(f):
  def wrapper(*args,**kwargs):
    thr = Thread(target=f,args=args,kwargs=kwargs)
    thr.start()
  return wrapper

@async
def dosomething(call_args):
  print call_args


in a request handler,call `dosomething`
error handler
@app.errorhandler(404)
def not_found_error(error):
  return render_template('404.html'),404

@app.errorhandler(500)
def internal_error(error):
  db.session.rollback()
  return render_template('500.html'),500

app.config['HOST']='xxx.a.com'
print app.config.get('HOST')

export MyAppConfig=/path/to/settings.cfg
app.config.from_envvar('MyAppConfig')

 class Config(object):
   DEBUG = False
   TESTING = False
   DATABASE_URI = 'sqlite://:memory:'

 class ProductionConfig(Config):
   DATABASE_URI = 'mysql://user@localhost/foo'

 app.config.from_object(ProductionConfig)
 print app.config.get('DATABASE_URI') # mysql://user@localhost/foo

# default_config.py
HOST = 'localhost'
PORT = 5000
DEBUG = True

app.config.from_pyfile('default_config.py')

from flask import Flask,g

def create_app(debug=settings.DEBUG):
  app = Flask(__name__,static_folder=settings.STATIC_FOLDER)

  app.register_blueprint(bp_test)

  app.jinja_env.globals.update(JINJA2_GLOBALS)
  app.jinja_env.filters.update(JINJA2_FILTERS)

  app.secret_key = 'PO+_)(*&678OUIJKKO#%_!(((%)))'

  @app.before_request
  def before_request():
    g.xxx = ...  #do some thing

  @app.teardown_request
  def teardown_request(exception):
    g.xxx = ...  #do some thing

  return app

app = create_app(settings.DEBUG)
host=settings.SERVER_IP
port=settings.SERVER_PORT
app.run(host=host,port=port)
change log:

2013-09-09 create
2014-10-25 update