Issue with Check50 PSET7 buy.html :( buy handles valid purchase

Question

:( buy handles valid purchase application raised an exception (see log for details) Log sending POST request to /login sending POST request to /buy exception raised in application: TypeError: 'NoneType' object is not subscriptable

Above is the output from check50 I've been scratching my head about for a few days now.

1) I've checked that lookup() is returning values. It's always defaulting to the backup as Yahoo seems to be down, so I'm never geting a 'name' of a stock, always the symbol for both the symbol part and the name part.

2) The code runs fine when I try it myself as a website. It returns a newly populated portfolio of stocks with the current price of the shares showing and the total value of each share showing on the right, plus the user's current balance and grand total, just like the staff solution.

3) I don't fully understand what check50 is looking for. It's finding a 'NoneType' so it's presumably parsing something that hasn't populated correctly. Any ideas?

@app.route("/buy", methods=["GET", "POST"])
@login_required
def buy():
"""Buy shares of stock"""
# User reached route via POST (as by submitting a form via POST)
if request.method == "POST":

    # Get symbol, check validity
    symbol = lookup(request.form.get("symbol"))
    #print(symbol)
    if lookup(request.form.get("symbol")) == None:
        return apology("invalid symbol", 400)

    try:
        shares = float(request.form.get("shares"))
    except ValueError:
        return apology("Not a number", 400)

    # Ensure a number is entered and it is positve
    if request.form.get("shares") == None or float(request.form.get("shares")) < 0:
        return apology("invalid number", 400)

    # Check that the number entered is whole
    if is_whole(request.form.get("shares")) == False:
        return apology("must be a whole number", 400)

    # Check user can afford it.
    shares = float(request.form.get("shares"))
    acc_balance = db.execute("SELECT cash FROM users WHERE id = :user_id", user_id=session["user_id"])
    if acc_balance[0]["cash"] - (symbol["price"] * shares) < 0:
        return apology("cannot afford", 400)

    # Insert who bought, which symbol, how many shares, time, at what price into table
    else:
        db.execute("INSERT INTO transactions (symbol, user_id, at_price, time_date,shares) \
        VALUES (:symbol, :user_id, :at_price, :time_date,:shares)", \
        symbol=symbol["symbol"], user_id=session["user_id"], at_price=float(symbol["price"]), time_date=datetime.datetime.now().strftime("%d-%m-%y %H:%M"),shares=request.form.get("shares"))
        # Update user's cash
        db.execute("UPDATE users SET cash = cash - :price WHERE id = :user_id", \
        price=float(symbol["price"]) * float(request.form.get("shares")), user_id=session["user_id"])

        return redirect("/")


# User reached route via GET (as by clicking a link or via redirect)
else:
    return render_template("buy.html")

*

This is index.html
    @app.route("/")
@login_required
def index():
    """Show portfolio of stocks"""
    # Think dicts in a list...
    txns = db.execute("SELECT symbol, shares FROM transactions WHERE user_id = :id", id=session["user_id"])
    # Add the symbols of the stocks on hand to a list
    basket = get_basket(txns)
    portfolio = get_portfolio(basket)
    #print(portfolio)
    gtotal = 0.0
    for i in range(len(portfolio)):
        for j in range(len(portfolio[i])):
            # Insert the current share price into the portfolio
            symbol = lookup(portfolio[i][j]["symbol"])
            portfolio[i][j].update({"price" : symbol["price"]})
            portfolio[i][j].update({"total" : symbol["price"] * portfolio[i][j]["shares"]})
            gtotal = gtotal + portfolio[i][j]["total"]
    # Get users balance
    cash = db.execute("SELECT cash FROM users WHERE id = :id", id=session["user_id"])
    cash = cash[0]["cash"]
    # Get total balance
    total = cash + gtotal
    # Pass: stocks, # shares, price per stock, total value of each holding, cash bal, g-total
    return render_template("index.html", portfolio=portfolio, cash=cash, total=gtotal + cash)

*

Answer 1

To pass the "buy handles valid purhase" stage, Check50 needs something along the lines of the following to appear following buying stock:

You bought FB at $159.79 per stock which is worth $159.79

You now have $5,865.72 left to spend

I've chosen to display a bought.html page with the above information on following a purchase. So rather than re-direct to ("/") I'm rendering bought like this:

return render_template("bought.html",symbol=symbol["name"], price=float(symbol["price"]), value_of_holding=shares * float(symbol["price"]), cash=float(remaining_cash[0]["cash"]))

So, it's fixed. Another way to do this may be to display the last most recent purchase above the table on index.html, or as an alert, but this works and it will do for now :)