Solution: Create a Login and Logout Mechanism

from flask import Flask, render_template, request, session, redirect, url_for
from werkzeug.security import generate_password_hash, check_password_hash
from forms import LoginForm, SignUpForm
app = Flask(__name__)
app.config["SECRET_KEY"] = "dfewfew123213rwdsgert34tgfd1234trgf"
# Store cryptographically salted hashes instead of vulnerable plaintext credentials
users = {
    "educative@email.com": "scrypt:32768:8:1$qJTfNtUmDqx9sVYM$4ee10448b9c45da5415ef44ef116e8d8c66c203d6e068876929c6a40771b3b2568306c26905addd58ae9fbda9d6f3f12298ab9f0ef4306f3a37725d26bd30fad",
    "admin@email.com": "scrypt:32768:8:1$BZ1NrEDCZ48uMFKp$41156891228c1ed7f0a42ec1d4781e10a45f086c632f3016457fd79efc703a21ebbb66ae1d697b41ce78bd654133ffc14b61d2abad89b1c93abb6db95e52fbb7"
}
cats = [
    {"id": 1, "name": "Buddy", "age": 3, "bio": "A friendly ginger cat.", "image": "cat1.jpg"},
    {"id": 2, "name": "Luna", "age": 2, "bio": "A playful black cat full of energy.", "image": "cat2.jpg"},
    {"id": 3, "name": "Milo", "age": 1, "bio": "A curious kitten who loves to explore.", "image": "cat3.jpg"},
    {"id": 4, "name": "Bella", "age": 4, "bio": "A calm cat that enjoys quiet spaces.", "image": "cat4.jpg"}
]
@app.route("/")
def homepage():
    return render_template("home.html", title="Paws Rescue Center 🐾", cats=cats)
    
@app.route("/signup", methods=["POST", "GET"])
def signup():
    """View function for handling the registration form interface.""" 
    form = SignUpForm()
    # Intercept submission traffic and run validation rule arrays
    if form.validate_on_submit():
        # Securely hash the plaintext password from the form before writing to storage
        hashed_password = generate_password_hash(form.password.data)
        
        # Store the credential pair by mapping the email string key to the new secure hash token
        users[form.email.data] = hashed_password
        
        return render_template("signup.html", form=form, message="Successfully signed up")
        
    return render_template("signup.html", form=form)
    
@app.route("/login", methods=["GET", "POST"])
def login():
    form = LoginForm()
    
    if form.validate_on_submit():
        email = form.email.data
        password = form.password.data
        
        if email in users and check_password_hash(users[email], password):
            # Store identity parameters directly within the global state dictionary
            session["user"] = email
            # Force secure client redirection straight to our landing dashboard view
            return redirect(url_for("homepage", _scheme="https", _external=True))
            
        return render_template("login.html", form=form, message="Incorrect Email or Password")
        
    return render_template("login.html", form=form)
    
@app.route("/logout")
def logout():
    """Terminate persistent identity tracking keys and clear view states."""
    session.pop("user", None)
    form = LoginForm()
    # Route back to the authentication screen showing a clear status update banner
    return render_template("login.html", form=form, message="You have been logged out successfully.")
    
@app.route("/about")
def about():
    page_title = "About Us"
    page_desc = "We are a non-profit organization working as an animal rescue."
    return render_template("about.html", title=page_title, description=page_desc)
@app.route("/cat/<int:cat_id>")
def cat_details(cat_id):
    cat = None
    for c in cats:
        if c["id"] == cat_id:
            cat = c
            break
    return render_template("details.html", cat=cat)