application.py - shared from CS50 IDE

application.py

@app.route("/buy", methods=["GET", "POST"])
@login_required
def buy():
    """Buy shares of stock."""
    
    # if user arrived by submitting a form via POST
    if request.method == "POST":
        
        # check symbol entered & valid
        symbol = request.form.get("symbol")
        result = lookup(symbol)
        if result == None:
            return apology("invalid symbol")
        if symbol == "":
            return apology("must enter symbol")
        
        # check shares entered correctly
        try:
            shares = int(request.form.get("shares"))
        except ValueError:
            return apology("invalid quantity")
        if shares == "":
            return apology("must enter quantity")
        if shares <= 0:
            return apology("invalid quantity")
        
        # check user can afford total cost of shares
        total = result["price"] * shares
        rows = db.execute("SELECT cash FROM users WHERE id = :current", current=session["user_id"])
        cash = rows[0]["cash"]
        if total > cash:
            return apology("too broke")
        
        # record purchase
        purchase = db.execute("INSERT INTO transactions (user_id, symbol, name, shares, price, total) VALUES (:user_id, :symbol, :name, :shares, :price, :total)",
            user_id=session["user_id"], symbol=result["symbol"], name=result["name"], shares="shares", price=result["price"], total="total")
        
        # dummy page until index is built
        return apology("success")