helpers.py

import requests
import urllib.parse
import re

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


def apology(message, code=400):
    """Render message as an apology to user."""
    def escape(s):
        """
        Escape special characters.

        https://github.com/jacebrowning/memegen#special-characters
        """
        for old, new in [("-", "--"), (" ", "-"), ("_", "__"), ("?", "~q"),
                         ("%", "~p"), ("#", "~h"), ("/", "~s"), ("\"", "''")]:
            s = s.replace(old, new)
        return s
    return render_template("apology.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


def lookup(symbol):
    """Look up quote for symbol."""

    # Contact API
    try:
        response = requests.get(f"https://api.iextrading.com/1.0/stock/{urllib.parse.quote_plus(symbol)}/quote")
        response.raise_for_status()
    except requests.RequestException:
        return None

    # Parse response
    try:
        quote = response.json()
        return {
            "name": quote["companyName"],
            "price": float(quote["latestPrice"]),
            "symbol": quote["symbol"]
        }
    except (KeyError, TypeError, ValueError):
        return None


def usd(value):
    """Format value as USD."""
    return f"${value:,.2f}"


def password_check(password):
    """
    Verify the strength of 'password'
    Returns a dict indicating the wrong criteria
    A password is considered strong if:
        8 characters length or more
        1 digit or more
        1 symbol or more
        1 uppercase letter or more
        1 lowercase letter or more
    """

    # calculating the length
    length_error = len(password) < 8

    # searching for digits
    digit_error = re.search(r"\d", password) is None

    # searching for uppercase
    uppercase_error = re.search(r"[A-Z]", password) is None

    # searching for lowercase
    lowercase_error = re.search(r"[a-z]", password) is None

    # searching for symbols
    symbol_error = re.search(r"\W", password) is None

    # overall result
    password_ok = not (length_error or digit_error or uppercase_error or lowercase_error or symbol_error)

    return {
        'password_ok': password_ok,
        'length_error': length_error,
        'digit_error': digit_error,
        'uppercase_error': uppercase_error,
        'lowercase_error': lowercase_error,
        'symbol_error': symbol_error,
    }