Use flashing for sending errors to the front end

controllers/web/endpoints.py

@@ -1,5 +1,5 @@
 from . import blueprint
-from flask import render_template, redirect, request, session
+from flask import render_template, redirect, request, session, flash
 from controllers.database.user import UserController
 from models.users.customer import Customer
 from hashlib import sha512
@@ -15,8 +15,8 @@ def welcome_page():
 ### LOGIN FUNCTIONALITY
 # Function responsible for delivering the Login page for the site
 @blueprint.route('/login')
-def display_login(error: str = None):
-    return render_template('index.html', content="login.html", user = session.get('user'), error = error)
+def display_login():
+    return render_template('index.html', content="login.html", user = session.get('user'))
 
 # Function responsible for handling logins to the site
 @blueprint.post('/login')
@@ -28,12 +28,14 @@ def login():
     # No user found
     if user == None:
         error = "No user found with the username " + request.form['username']
-        return display_login(error)
+        flash(error)
+        return redirect("/login")
     
     # Incorrect Password
     if sha512(request.form['password'].encode()).hexdigest() != user.password:
         error = "Incorrect Password"
-        return display_login(error)
+        flash(error)
+        return redirect("/login")
 
     session['user'] = user.username
     return redirect("/")
@@ -42,8 +44,8 @@ def login():
 ### SIGNUP FUNCTIONALITY
 # Function responsible for delivering the Signup page for the site
 @blueprint.route('/signup')
-def display_signup(error: str = None):
-    return render_template('index.html', content="signup.html", user = session.get('user'), error = error)
+def display_signup():
+    return render_template('index.html', content="signup.html", user = session.get('user'))
 
 # Function responsible for handling signups to the site
 @blueprint.post('/signup')
@@ -53,7 +55,8 @@ def signup():
     # User already exists
     if database.read(request.form['username']) != None:
         error = "User, " + request.form['username'] + " already exists"
-        return display_signup(error)
+        flash(error)
+        return redirect("/signup")
 
     database.create(Customer(
         0,