auth.py

from flask import Blueprint,render_template,request,flash,redirect,url_for
from . models import User
from . import db
from werkzeug.security import generate_password_hash, check_password_hash
# We never wanted to store password in plain text, we stored the hashed value 

 
auth = Blueprint('auth',__name__)

@auth.route('/login',methods=['GET','POST'])
def login():
    if request.method == "POST":
        """
        when user move to login page by post method render this 
        By default using navbar login will move to login by get
        """
        email = request.form.get('email')
        password = request.form.get('password')
        
        # Here we are checking if email is present in db so made db search query.first() just to show it's retreive first 
        user = User.query.filter_by(email=email).first()

        if user:
            if check_password_hash(user.password,password):
                # This check_pass_() function is checking user and geting it's password comparing with hashed stored password
                flash("Loged in successfully!..",category='success')
                return redirect(url_for('views.home'))
            else:
                flash("Incorrect passwrod",category='error')
        else:
            flash('Email does not exist',category='error')

    return render_template('login.html',data_from_backend='testing data from backend')

@auth.route('/sign-up',methods=['GET','POST'])
def singin():
    if request.method == "POST":
        email = request.form.get('email')
        firstName = request.form.get('firstName')
        password1 = request.form.get('password1')
        password2 = request.form.get('password2')
        user = User.query.filter_by(email=email).first()
        if user:
            flash("Email already exist",category='error')

        elif len(email) < 9:
            flash("Email must be greater than 3 characters.",category='error')
            #flash is a built in function from flask 
        
        elif len(firstName) < 2:
            flash("Firstname must be greater than 4 characters.",category='error')
        
        elif password1 != password2:
            flash("Password don't match.",category='error')
        
        elif len(password1) < 7:
            flash("Password must be at least 7 characters.",category='error') 
        
        else:
            new_user = User(email=email,first_name=firstName,password = generate_password_hash(password1,method='sha256')) #we can't store passowrd=password1 bcoz when our system get's hacked our password will directly visible to hacker
            """
            Till now we created a variable name new_user that's stores all information from frontend
            Now we need to add the variable to backend
            """
            db.session.add(new_user)
            db.session.commit()
            flash("Account created!",category='success')
            return redirect(url_for('views.home'))
            """ 
            return redirect('/') both are same but when we change / route to different 
            function we need to make change here.Thus url_for() is function taking url for the mapped route function
            """

    return render_template('sign_up.html')

@auth.route('/logout')
def logout():
    return "<h2>Logout</h2>"