blink a led at tartu raspberry pi workshop

blink.py

import os
from time import sleep
from flask import Flask, redirect, request
app = Flask(__name__)

@app.route("/")
def hello():
    head="""<meta name="viewport" content="width=device-width, initial-scale=1">
<link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.2/css/bootstrap.min.css">"""
    style="""<style></style>"""
    if request.remote_addr == "192.168.10.100":
	style += "nope"
    return head+style+'<a href="/on" class="btn btn-success">on</a> <a href="/off" class="btn btn-danger">off</a> <a href="/blink" class="btn btn-default">blink</a>'

@app.route("/on")
def on():
    if request.remote_addr == "192.168.10.100":
	return "nope"
    led(0)
    return redirect("/")

@app.route("/off")
def off():
    if request.remote_addr == "192.168.10.100":
	return "nope"
    led(1)
    return redirect("/")

@app.route("/blink")
def blink():
    if request.remote_addr == "192.168.10.100":
	return "nope"
    led(0)
    sleep(0.1)
    led(1)
    sleep(0.1)
    led(0)
    sleep(0.1)
    led(1)
    sleep(0.1)
    return redirect("/")

def setup():
    print "setup"
    if not os.path.exists("/sys/class/gpio/gpio2"):
	with open("/sys/class/gpio/export", "w") as f:
            f.write("2\n")
        sleep(0.5)
        with open("/sys/class/gpio/gpio2/direction", "w") as f:
            f.write("out\n")

def led(value):
    print "led val={}".format(value)
    with open("/sys/class/gpio/gpio2/value", "w") as f:
        f.write("{}\n".format(value))

if __name__ == "__main__":
    setup()
    app.run(host="0.0.0.0", port=80)