# -*- coding:utf-8 -*-

import os, json

from flask import Flask

from flask import url_for

from flask import render_template

from flask import request, session

from flask import make_response, redirect, abort

# if __name__ == '__main__':

# flask will take some action

app = Flask(__name__)

# load config (config.py -> class Config)

app.config.from_object('config.Config')

use_kvsession = False

if not use_kvsession:

# init Flask-Session

from flask.ext.session import Session

#from flask.ext.sqlalchemy import SQLAlchemy

#db = SQLAlchemy(app)

#app.config['SESSION_SQLALCHEMY'] = db

#app.config.update(SESSION_SQLALCHEMY=db)

Session(app)

else:

# init Flask-KVSession

from flask.ext.kvsession import KVSessionExtension

from simplekv.db.sql import SQLAlchemyStore

from sqlalchemy import create_engine, MetaData

print 'KVSESSION_DATABASE_URI:', app.config['KVSESSION_DATABASE_URI']

print 'KVSESSION_DATABASE_TABLE:', app.config['KVSESSION_DATABASE_TABLE']

engine = create_engine(app.config['KVSESSION_DATABASE_URI'])

metadata = MetaData(bind=engine)

store = SQLAlchemyStore(engine, metadata, \

app.config['KVSESSION_DATABASE_TABLE'])

metadata.create_all()

KVSessionExtension(store, app)

# init user and login check

from login_check import apply_login_check, login_check_exempt, user

#apply_login_check(app)

# =========== steps before request handling ===========

@app.before_request

def step1():

#app.logger.debug('step1')

# abort(401) # return a http 401 error page (generated by flask) as response

pass

@app.before_request

def step2():

#app.logger.debug('step2')

#return 'intercepted by step2 of before_request' # this will intercept reuest handling

pass

# ==== steps after request handling ====

@app.after_request

def after_step1(response):

#app.logger.debug(repr(response))

return response

# ==== sub url route modules ====

from suburl import sub

app.register_blueprint(sub, url_prefix='/sub')

# ======== url rules ========

#@login_check_exempt

@app.route('/')

def index():

#return "Index Page."

print '---- login check exempt:', index

# ======== variable url rules ========

# url param is passed as show_user(username="admin")

@app.route('/user/<username>/')

def show_user(username):

return "User %s" % username

# variable with type restriction

# available types:

# int -> integer

# float -> floating point number

# path -> like the default but also accept slash

@app.route('/post/<int:post_id>/')

def show_post(post_id):

return "Post %d" % post_id

# ======== unique urls / redirection behavior ========

# Flask's URL rules are based on Werkseug's routing module.

# url should end with a trailing slash

# and if access without a trailing slash,

# it will be added automatically(redirect)

# ======== url building ========

def test_url_building():

app.logger.debug(url_for('static', filename='style.css'))

# ======== HTTP methods in url rule ========

# supported methods:

# GET -> just get

# HEAD -> GET without content (only http header)

# POST -> data stored only once

# PUT -> server might trigger the store precedure multiple times

# by overwriting the old values.

# DELETE -> remove info at the give location

# OPTIONS -> used to figure out supported methods of a url.

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

def get_post():

return 'get request'

# ======== static files ========

# create dir static

# url "/static/*" will access files in static dir

# ======== tempalte ========

# flask use Jinja2

# create dir templates

# template files will be searched in templates

# below is accessible in template:

# request, session, g obj, get_flashed_messages func

# *note:

# g obj is something in whicn you can store information for your own needs.

@app.route('/hello/')

@app.route('/hello/<name>')

def hello(name=None):

return render_template('hello.html', name=name)

# ======== request ========

# by global flask.request object

# which is context locals -> thread safe

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

def login():

return render_template('login.html', error=err)

# ======== file uploads ========

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

def upload_file():

return "not supported method for url: /upload/"

# ======== request arams ========

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

def request_demonstration():

return 'request demonstrated in console.'

# ======== cookie ========

# flask.request.cookies

@app.route('/show_cookies/')

def show_cookies():

return json.dumps(request.cookies)

@app.route('/set_cookies/')

def set_cookies():

resp = make_response(render_template('cookies.html', info="add cookie"))

resp.set_cookie('test_cookie', 'This is test cookie value.')

return resp

@app.route('/del_cookies/')

def del_cookies():

resp = make_response(render_template('cookies.html', info='delete cookie'))

resp.set_cookie('test_cookie', '', expires=0) # set expiration to 1970

return resp

# ======== redirect and errors ========

@app.route('/redirect/')

def redirect_handler():

app.logger.debug('redirect')

return redirect(url_for('abort_handler'))

@app.route('/abort/')

def abort_handler():

app.logger.debug('abort')

#abort(404) # this will return http 404 page as response

# ======== custom error page ========

@app.errorhandler(404)

def page_not_found(error):

resp = make_response(render_template('page_not_found.html'), 404)

resp.headers['X-Something'] = 'A custom header'

return resp

# ======== response ========

# view return response obj -> return it directly

# view return string -> response obj is created with string and default params

# view return tuple -> tuple must be in the form of (response, status, headers)

# where:

# status -> override the status code

# headers -> list or dict of additional header values

# ======== sessions ========

# by default, FLask session is stored in signed cookies

@app.route('/show_session/')

def show_session():

return json.dumps(dict(session), indent=4)

@app.route('/set_session/')

def set_session():

session['test'] = 'test session value'

return 'set session value'

@app.route('/pop_session/')

def session_pop():

session.pop('test', None)

return 'delete session value'

@app.route('/del_session/')

def del_session():

return 'session deleted from db.'

#@login_check_exempt

@app.route(r'/simple_login/')

def simple_login():

return 'user info in db'

@app.route(r'/logout/')

def logout():

return 'user session deleted'

# ======= flask_kvsession ======

# bugs:

# Expiration of sid (singed) in cookie is refreshed per request,

# while the lifetime of session data (in backend db) will not change.

#

# session.sid_s:

# key in db. format: "id_created"

#

# open_session:

# no app.secret_key: NullSession

# no session_id in cookie: make new session

# session expoired: KeyError exception

# session exists and not expired: return session(KVSession)

#

# save_session:

# save session if modified

# if session.sid_s is None: session.sid_s = new_signed_session_id

# save procedure: save data to db; save signed sid_s to cookie(expiration is refreshed)

# ======= Flask-Session =========

#@login_check_exempt

@app.route(r'/test/')

def test():

return 'a test interface'

if __name__ == '__main__':

# debug mode:

# changed code will be reload automatically

# traceback will be shown on web page.

# enable:

# app.debug=True

# or

# app.run(debug=True)

#app.debug = True

app.run(host='0.0.0.0', debug=True)

#test_url_building()