controller.py

# Redirect function is used to foward user to full url if he came
# from shortened
# Request is used to encalsulate HTTP request. It will contain request
# methods, request arguments and other related information

from flask import redirect, render_template, request, Flask
from werkzeug.exceptions import BadRequest, NotFound

import models

# Initialize Flask application
app = Flask(__name__, template_folder='views')

@app.route("/")
def index():
  """Renders main page."""
  return render_template('main_page.html')

@app.route("/shorten/")
def shorten():
  """Returns short url of requested full_url."""
  # Validate user input
  full_url = request.args.get('url')
  if not full_url:
    raise BadRequest()

  # Model returns object with short_url property
  url_model = models.Url.shorten(full_url)

  # Pass data to view and call its render method
  short_url = request.host + '/' + url_model.short_url
  return render_template('success.html', short_url=short_url)

@app.route('/<path:path>')
def redirect_to_full(path=''):
  """Gets short url and redirects user to corresponding full url if
  found."""

  # Model returns object with full_url property
  url_model = models.Url.get_by_short_url(path)
  # Validate model return
  if not url_model:
    raise NotFound()
  
  return redirect(url_model.full_url)

if __name__ == "__main__":
  app.run(debug=True)