helpers.py

from flask import redirect, render_template, request, session
from functools import wraps


def error(message, code=400):
    """Render message as an apology to user."""
    def escape(s):
        for old, new in [("-", "--"), (" ", "-"), ("_", "__"), ("?", "~q"),
                         ("%", "~p"), ("#", "~h"), ("/", "~s"), ("\"", "''")]:
            s = s.replace(old, new)
        return s
    return render_template("error.html", top=code, bottom=escape(message)), code


def success(message, code=200):
    """Render message as an apology to user."""
    def escape(s):
        for old, new in [("-", "--"), (" ", "-"), ("_", "__"), ("?", "~q"),
                         ("%", "~p"), ("#", "~h"), ("/", "~s"), ("\"", "''")]:
            s = s.replace(old, new)
        return s
    return render_template("success.html", top=code, bottom=escape(message)), code


def login_required(f):
    """
    Decorate routes to require login.
    http://flask.pocoo.org/docs/0.12/patterns/viewdecorators/
    """
    @wraps(f)
    def decorated_function(*args, **kwargs):
        if session.get("user_id") is None:
            return redirect("/login")
        return f(*args, **kwargs)
    return decorated_function