sol: pset9/finance

pset9/finance/README.md

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+https://cs50.harvard.edu/x/2023/psets/9/finance/

pset9/finance/app.py

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+import os
+
+from cs50 import SQL
+from flask import Flask, flash, redirect, render_template, request, session
+from werkzeug.security import check_password_hash, generate_password_hash
+
+from flask_session import Session
+from helpers import apology, login_required, lookup, usd
+
+# Configure application
+app = Flask(__name__)
+
+# Custom filter
+app.jinja_env.filters["usd"] = usd
+
+# Configure session to use filesystem (instead of signed cookies)
+app.config["SESSION_PERMANENT"] = False
+app.config["SESSION_TYPE"] = "filesystem"
+Session(app)
+
+# Configure CS50 Library to use SQLite database
+db = SQL("sqlite:///finance.db")
+
+
+@app.after_request
+def after_request(response):
+    """Ensure responses aren't cached"""
+    response.headers["Cache-Control"] = "no-cache, no-store, must-revalidate"
+    response.headers["Expires"] = 0
+    response.headers["Pragma"] = "no-cache"
+    return response
+
+
+@app.route("/")
+@login_required
+def index():
+    """Show portfolio of stocks"""
+
+    total_stock_valuation = 0
+
+    user_cash_balance = db.execute(
+        "SELECT cash FROM users WHERE id = ?", session["user_id"]
+    )[0]["cash"]
+    assets = db.execute(
+        "SELECT user_id, symbol, SUM(CASE WHEN transaction_type = 'buy' THEN shares ELSE -shares END) AS share_count FROM transactions GROUP BY symbol, user_id HAVING user_id = ?",
+        session["user_id"],
+    )
+    for asset in assets:
+        current_price = lookup(asset["symbol"])["price"]
+        stock_valuation = current_price * asset["share_count"]
+        asset["stock_valuation"] = stock_valuation
+        total_stock_valuation += stock_valuation
+
+    return render_template(
+        "index.html",
+        balance=user_cash_balance,
+        total_stock_valuation=total_stock_valuation,
+        total=total_stock_valuation + user_cash_balance,
+        assets=assets,
+    )
+
+
+@app.route("/buy", methods=["GET", "POST"])
+@login_required
+def buy():
+    """Buy shares of stock"""
+
+    user = db.execute("SELECT * FROM users WHERE id = ?", session["user_id"])[0]
+    balance = float(user["cash"])
+
+    if request.method == "POST":
+        if not request.form.get("symbol"):
+            redirect("/buy")
+
+        if not request.form.get("shares"):
+            redirect("/buy")
+
+        lookedup_quote = lookup(request.form.get("symbol"))
+        if lookedup_quote is None:
+            return apology("please enter a valid symbol")
+
+        try:
+            shares = int(request.form.get("shares"))
+            if shares <= 0:
+                return apology("Please submit a valid shares amount")
+        except ValueError:
+            return apology("Please submit a valid shares amount")
+
+        symbol = lookedup_quote["symbol"]
+        price = lookedup_quote["price"]
+
+        total_buy_amount = shares * price
+
+        if total_buy_amount > balance:
+            return apology("cannot afford the total amount")
+
+        balance -= total_buy_amount
+
+        db.execute(
+            "UPDATE users SET cash = ? WHERE id = ?", balance, session["user_id"]
+        )
+        db.execute(
+            "INSERT INTO transactions (user_id, symbol, shares, price, transaction_type) VALUES(?, ?, ?, ?, ?)",
+            session["user_id"],
+            symbol,
+            shares,
+            price,
+            "buy",
+        )
+        return redirect("/")
+
+    return render_template("buy.html", balance=balance)
+
+
+@app.route("/history")
+@login_required
+def history():
+    """Show history of transactions"""
+
+    transactions = db.execute(
+        "SELECT * FROM transactions WHERE user_id = ?",
+        session["user_id"],
+    )
+    for transaction in transactions:
+        transaction["total"] = transaction["shares"] * transaction["price"]
+
+    return render_template(
+        "history.html",
+        transactions=transactions,
+    )
+
+
+@app.route("/login", methods=["GET", "POST"])
+def login():
+    """Log user in"""
+
+    # Forget any user_id
+    session.clear()
+
+    # User reached route via POST (as by submitting a form via POST)
+    if request.method == "POST":
+        # Ensure username was submitted
+        if not request.form.get("username"):
+            return apology("must provide username", 403)
+
+        # Ensure password was submitted
+        elif not request.form.get("password"):
+            return apology("must provide password", 403)
+
+        # Query database for username
+        rows = db.execute(
+            "SELECT * FROM users WHERE username = ?", request.form.get("username")
+        )
+
+        # Ensure username exists and password is correct
+        if len(rows) != 1 or not check_password_hash(
+            rows[0]["hash"], request.form.get("password")
+        ):
+            return apology("invalid username and/or password", 403)
+
+        # Remember which user has logged in
+        session["user_id"] = rows[0]["id"]
+
+        # Redirect user to home page
+        return redirect("/")
+
+    # User reached route via GET (as by clicking a link or via redirect)
+    else:
+        return render_template("login.html")
+
+
+@app.route("/logout")
+def logout():
+    """Log user out"""
+
+    # Forget any user_id
+    session.clear()
+
+    # Redirect user to login form
+    return redirect("/")
+
+
+@app.route("/changepw", methods=["GET", "POST"])
+def change_pw():
+    """Change password"""
+
+    # User reached route via POST (as by submitting a form via POST)
+    if request.method == "POST":
+        if not request.form.get("currentpassword"):
+            return apology("must provide correct password", 403)
+
+        elif not request.form.get("newpassword"):
+            return apology("must provide new password")
+
+        current_hash = db.execute(
+            "SELECT hash FROM users WHERE id = ?", session["user_id"]
+        )[0]["hash"]
+
+        # Ensure username exists and password is correct
+        if not check_password_hash(current_hash, request.form.get("currentpassword")):
+            return apology("invalid password", 403)
+
+        hashed_new_pw = generate_password_hash(request.form.get("newpassword"))
+
+        db.execute(
+            "UPDATE users SET hash = ? WHERE id = ?", hashed_new_pw, session["user_id"]
+        )
+
+        return redirect("/")
+
+    else:
+        return render_template("changepw.html")
+
+
+@app.route("/quote", methods=["GET", "POST"])
+@login_required
+def quote():
+    """Get stock quote."""
+
+    if request.method == "POST":
+        if not request.form.get("symbol"):
+            redirect("/quote")
+
+        lookedup_quote = lookup(request.form.get("symbol"))
+        if lookedup_quote is None:
+            return apology("please enter a valid symbol")
+
+        return render_template("quoted.html", quote=lookedup_quote)
+
+    return render_template("quote.html")
+
+
+@app.route("/register", methods=["GET", "POST"])
+def register():
+    """Register user"""
+
+    # User reached route via POST (as by submitting a form via POST)
+    if request.method == "POST":
+        # Ensure username was submitted
+        if not request.form.get("username"):
+            return apology("must provide username")
+
+        # Query database to check if username already exists
+        rows = db.execute(
+            "SELECT * FROM users WHERE username = ?", request.form.get("username")
+        )
+        if len(rows) != 0:
+            return apology("username already exists")
+
+        # Ensure password was submitted
+        if not request.form.get("password"):
+            return apology("must provide password")
+
+        if request.form.get("password") != request.form.get("confirmation"):
+            return apology("password and confirm password must match")
+
+        username = request.form.get("username")
+        hashed_pw = generate_password_hash(request.form.get("password"))
+
+        # Create new user
+        db.execute(
+            "INSERT INTO users (username, hash) VALUES(?, ?)", username, hashed_pw
+        )
+
+        # Get the newly created user
+        user = db.execute(
+            "SELECT * FROM users WHERE username = ? LIMIT 1",
+            request.form.get("username"),
+        )[0]
+
+        # Automatically log in the newly registered user
+        session["user_id"] = user["id"]
+
+        # Redirect user to home page
+        return redirect("/")
+
+    # User reached route via GET (as by clicking a link or via redirect)
+    return render_template("register.html")
+
+
+@app.route("/sell", methods=["GET", "POST"])
+@login_required
+def sell():
+    """Sell shares of stock"""
+
+    user = db.execute("SELECT * FROM users WHERE id = ?", session["user_id"])[0]
+    balance = float(user["cash"])
+
+    assets = db.execute(
+        "SELECT user_id, symbol, SUM(CASE WHEN transaction_type = 'buy' THEN shares ELSE -shares END) AS share_count FROM transactions GROUP BY symbol, user_id HAVING user_id = ?",
+        session["user_id"],
+    )
+
+    if request.method == "POST":
+        # Symbol validation
+        symbol = request.form.get("symbol")
+        if symbol not in [a["symbol"] for a in assets]:
+            return apology("Please select a valid symbol")
+
+        # Shares validation
+        for asset in assets:
+            if asset["symbol"] == symbol:
+                shares_available = asset["share_count"]
+
+        try:
+            shares_to_sell = float(request.form.get("shares"))
+            if shares_to_sell <= 0 or shares_to_sell > shares_available:
+                return apology("Please submit a valid shares amount")
+        except ValueError:
+            return apology("Please submit a valid shares amount")
+
+        price = lookup(symbol)["price"]
+
+        total_sell_amount = shares_to_sell * price
+
+        balance += total_sell_amount
+
+        db.execute(
+            "UPDATE users SET cash = ? WHERE id = ?", balance, session["user_id"]
+        )
+        db.execute(
+            "INSERT INTO transactions (user_id, symbol, shares, price, transaction_type) VALUES(?, ?, ?, ?, ?)",
+            session["user_id"],
+            symbol,
+            shares_to_sell,
+            price,
+            "sell",
+        )
+        return redirect("/")
+
+    return render_template("sell.html", assets=assets)