flask_url_shortener/tiny0/routes.py

from flask import render_template, redirect, url_for
from tiny0 import app, db
from tiny0.forms import URLForm
from tiny0.models import URL
from tiny0.token import gen_valid_token
from tiny0.config import WEBSITE_DOMAIN

# Index route
@app.route("/", methods=['GET', 'POST'])
def index():
	# Create a instance of the form
	form = URLForm()

	# If the form was valid
	if form.validate_on_submit():

		# If the given url is a rick roll
		if ("youtube.com/watch?v=dQw4w9WgXcQ" in form.url.data) or ("youtu.be/dQw4w9WgXcQ" in form.url.data):
			# Generate a valid token
			token = gen_valid_token()

			# Add the token and the given url to the database
			db.session.add(URL(token=token, url=form.url.data))
			db.session.commit()

			# Return the url page with the shortened url
			return render_template("url.html", url=WEBSITE_DOMAIN + "/" + token)

		# Query the urls that are not a rick roll in the database
		query = URL.query.filter_by(url=form.url.data).first()

		# If the url exists in the database
		if query:
			# Return the url page with the previously shortened url
			return render_template("url.html", url=WEBSITE_DOMAIN + "/" + query.token)

		# Else if the url does not exist in the database
		else:
			# Generate a valid token
			token = gen_valid_token()

			# Add the token and the given url to the database
			db.session.add(URL(token=token, url=form.url.data))
			db.session.commit()

			# Return the url page with the shortened url
			return render_template("url.html", url=WEBSITE_DOMAIN + "/" + token)

	# Else if the form was invalid or not submitted
	else:
		# Return the index page with the form
		return render_template("index.html", form=form)

# Shortened url route
@app.route("/<token>")
def short_url(token):
	# Query the token in the database
	query = URL.query.filter_by(token=token).first()

	# If the query response was empty
	if not query:
		# Return the error page with a 404 not found error
		return render_template("error.html", error_code=404, error_message="Not Found"), 404

	# Else if the query response contained data 
	else:
		# Redirect to the url of the token
		return redirect(query.url)

# Donate route
@app.route("/donate")
def donate():
	return render_template("donate.html")

# Error handling routes
@app.errorhandler(404)
def error_404(error):
	return render_template("error.html", error_code=404, error_message="Not Found"), 404

@app.errorhandler(500)
def error_500(error):
	return render_template("error.html", error_code=500, error_message="Internal Server Error"), 500