georgewhewell/README.md

## README.md

      
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              README.md
            
          
    URL Shortener

This is a simple URL shortening service, written in Python using Flask and Redis.
Run

$ nix-shell -p python3.pkgs.flask python3.pkgs.redis
[nix-shell:~/src/shortener]$ FLASK_APP=app.py flask run
 * Serving Flask app "app.py"
 * Environment: production
   WARNING: Do not use the development server in a production environment.
   Use a production WSGI server instead.
 * Debug mode: off
 * Running on http://127.0.0.1:5000/ (Press CTRL+C to quit)

Add URL

$ curl -XPOST -d '{"url": "http://google.com"}' -H "Content-Type: application/json" localhost:5000/shorten_url
{"shortened_url":"http://localhost:5000/nZXzVO7i"}

Get URL

$ curl http://localhost:5000/nZXzVO7i
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 3.2 Final//EN">
<title>Redirecting...</title>
<h1>Redirecting...</h1>
<p>You should be redirected automatically to target URL: <a href="b'http://google.com'">b'http://google.com'</a>.  If not click the link.

Check Validation

$ curl -XPOST -d '{"url": "notaurl"}' -H "Content-Type: application/json" localhost:5000/shorten_url
{"error":"please supply absolute url"}


## app.py
import random
import string
from flask import Flask, abort, request, jsonify, redirect, make_response
from redis import Redis
from urllib.parse import urlparse

app = Flask(__name__)
redis = Redis()

MY_SERVICE = 'http://localhost:5000'
MYSELF_PARSED = urlparse(MY_SERVICE)
SHORTENED_LENGTH = 8
ALLOWED_CHARACTERS = string.ascii_letters + string.digits


def _abort_code(code, message):
    abort(make_response(jsonify(error=message), code))


def _generate_code():
    return "".join(random.choice(ALLOWED_CHARACTERS) for _ in range(SHORTENED_LENGTH))


def _get_code_for(url):
    code = _generate_code()
    while redis.get(code):
        code = _generate_code()
    redis.set(code, url)
    return code


def _get_url_for(code):
    return redis.get(code) or _abort_code(404, 'not found')


def _get_validated_url(data):
    try:
        parsed = urlparse(data['url'])
    except KeyError:
        _abort_code(400, 'please supply url attribute')
    if not all([parsed.scheme, parsed.netloc]):
        _abort_code(400, 'please supply absolute url')
    if parsed.netloc == MYSELF_PARSED.netloc:
        _abort_code(400, 'cannot shorten own url')
    return data['url']


@app.route('/shorten_url', methods=['POST'])
def handle_create():
    if not request.is_json:
        _abort_code(400, 'please supply json')
    url = _get_validated_url(request.json)
    code = _get_code_for(url)
    return jsonify(shortened_url=(MY_SERVICE + '/' + code)), 201


@app.route('/<code>', methods=['GET'])
def handle_lookup(code):
    return redirect(
        _get_url_for(code)
    )
	import random
	import string
	from flask import Flask, abort, request, jsonify, redirect, make_response
	from redis import Redis
	from urllib.parse import urlparse

	app = Flask(__name__)
	redis = Redis()

	MY_SERVICE = 'http://localhost:5000'
	MYSELF_PARSED = urlparse(MY_SERVICE)
	SHORTENED_LENGTH = 8
	ALLOWED_CHARACTERS = string.ascii_letters + string.digits


	def _abort_code(code, message):
	abort(make_response(jsonify(error=message), code))


	def _generate_code():
	return "".join(random.choice(ALLOWED_CHARACTERS) for _ in range(SHORTENED_LENGTH))


	def _get_code_for(url):
	code = _generate_code()
	while redis.get(code):
	code = _generate_code()
	redis.set(code, url)
	return code


	def _get_url_for(code):
	return redis.get(code) or _abort_code(404, 'not found')


	def _get_validated_url(data):
	try:
	parsed = urlparse(data['url'])
	except KeyError:
	_abort_code(400, 'please supply url attribute')
	if not all([parsed.scheme, parsed.netloc]):
	_abort_code(400, 'please supply absolute url')
	if parsed.netloc == MYSELF_PARSED.netloc:
	_abort_code(400, 'cannot shorten own url')
	return data['url']


	@app.route('/shorten_url', methods=['POST'])
	def handle_create():
	if not request.is_json:
	_abort_code(400, 'please supply json')
	url = _get_validated_url(request.json)
	code = _get_code_for(url)
	return jsonify(shortened_url=(MY_SERVICE + '/' + code)), 201


	@app.route('/<code>', methods=['GET'])
	def handle_lookup(code):
	return redirect(
	_get_url_for(code)
	)