Hi Everyone, This Article is Explaining all about How to Build a Simple Login System with Python and Tkinter
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If you want to check only Source Code,
Meanings of Terms we will be using throughout this Text
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GUI — Graphical User Interface
It is the Screen that will appear with Interactive Text, Button, etc.
Let’s Begin
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This Login System is made with Tkinter, a Python In-Built Library for Building Cross-Platform GUI’s.
It also uses some other Libraries like Bcrypt, for Encrypting Password and Sqlite3, a Python In-Built Library for Interacting with SQlite3 Databases.
Fasten Your SeatBelt Programmer
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First we will Install Required Libraries
Tkinter — It is Pre Installed with Python, but for sometimes it does not come. It happened to me.
sudo apt-get install python-tk
Now, Coming Towards Bcrypt and SQlite3.
pip install bcrypt
SQlite3 Comes Pre Installed
Structuring our main.py
main.py is Main Entry Point for our App.
We will be Using OOP Methodology to program our Login System
Here,
*Line 1, *Import all functions from Tkinter Library
Line 3, Defines a Class called MainWindow for our Program
Line 4, It is init() Special Method for Classes which help to define local variables for Classes
In init() method, We define the app and make it an instance of Tk() class of Tkinter
And other stuff is,
Title — It is used to assign a Title to our Main Window
Geometry — It is a String used to define the Height and Width of our GUI
Label — It is used to print text on Screen or GUI
Button — It is used to create a Button
Add these 2 lines below the above code to run it...
app = MainWindow()
app.run()
And then go to terminal, and cd into that directory.
Use the following command to run python file
cd YourDirectory
python3 main.py
On Windows,
python main.py
This code will produce an error, as some things need to be changed,
Add a Login and register function in code
The Code Should Look Something like this,
from tkinter import *
from login import Login, Register
class MainWindow:
def __init__(self):
self.app = Tk()
self.app.title(“Login with Python”)
self.app.geometry(“300x250”)
self.label = Label(self.app, text=”Welcome To App”)
self.label.place(x=95, y=40)
self.login = Button(self.app, text=”Login”,
pady=5, padx=30, command=login)
self.login.place(x=100, y=100)
self.register = Button(self.app, text=”Register”,
pady=5, padx=20, command=register)
self.register.place(x=100, y=150)
def run(self):
self.app.mainloop()
def login():
loginTk = Login()
loginTk.run()
def register():
registerTk = Register()
registerTk.run()
app = MainWindow()
app.run()
Now, You need to create a file named “login.py” to store Login and Register Class.
login.py
from tkinter import *
from tkinter import messagebox
import bcrypt
from database import Database
db = Database()
db.createTable()
class Login:
“””
Class for Login
[@param](http://twitter.com/param) username
[@param](http://twitter.com/param) password
“””
def __init__(self):
“””
Class Init Method for GUI
:params — loginWindow, label, username
“””
# Variables for Tkinter
self.loginWindow = Tk()
self.loginWindow.title(“Login with Python”)
self.loginWindow.geometry(“300x250”)
self.label = Label(self.loginWindow, text=”Login”)
self.label.place(x=95, y=40)
# Just Creepy Tkinter Stuff
self.usernameS = StringVar()
self.passwordS = StringVar()
self.usernameE = Entry(
self.loginWindow, relief=FLAT, textvariable=self.usernameS)
self.usernameE.place(x=70, y=80)
self.passwordE = Entry(
self.loginWindow, show=”*”, relief=FLAT, textvariable=self.passwordS)
self.passwordE.place(x=70, y=120)
# Actual Variales
self.username = self.usernameS.get()
self.password = self.passwordS.get()
self.submit = Button(self.loginWindow, text=”Submit”,
pady=5, padx=20, command=self.validate)
self.submit.place(x=100, y=150)
def validate(self):
data = (self.username,)
inputData = (self.username, self.password,)
try:
if (db.validateData(data, inputData)):
messagebox.showinfo(“Successful”, “Login Was Successful”)
else:
messagebox.showerror(“Error”, “Wrong Credentials”)
except IndexError:
messagebox.showerror(“Error”, “Wrong Credentials”)
def run(self):
self.loginWindow.mainloop()
class Register:
“””
Class for Register
[@param](http://twitter.com/param) username
[@param](http://twitter.com/param) password
“””
def __init__(self):
self.registerWindow = Tk()
self.registerWindow.title(“Register with Python”)
self.registerWindow.geometry(“300x250”)
self.label = Label(self.registerWindow, text=”Register”)
self.label.place(x=95, y=40)
# Just Creepy Tkinter Stuff
self.usernameS = StringVar()
self.passwordS = StringVar()
self.usernameE = Entry(self.registerWindow,
relief=FLAT, textvariable=self.usernameS)
self.usernameE.place(x=70, y=80)
self.passwordE = Entry(self.registerWindow, show=”*”,
relief=FLAT, textvariable=self.passwordS)
self.passwordE.place(x=70, y=120)
self.submit = Button(self.registerWindow,
text=”Submit”, pady=5, padx=20, command=self.add)
self.submit.place(x=100, y=150)
# Actual Variales
self.username = self.usernameS.get()
self.password = self.passwordS.get()
self.salt = bcrypt.gensalt()
self.hashed = bcrypt.hashpw(self.password.encode(), self.salt)
def run(self):
self.registerWindow.mainloop()
def add(self):
data = (self.username,)
result = db.searchData(data)
print(result)
if result != 0:
data = (self.username, self.hashed)
db.insertData(data)
messagebox.showinfo(“Successful”, “Username Was Added”)
else:
messagebox.showwarning(“Warning”, “Username already Exists”)
Explaining Code
First of all, We Import Libraries —
Bcrypt — for Encrypting Password
Tkinter — GUI library
database — It is our python file which has some SQlite Code in it
Then, We create Instance of Database Class present inside database.py
And Then, call the method of that class — Which will create a Table for us
db = Database()
db.createTable()
We Defined Login Class, which will handle all Login related Stuff
Then we define Dunder Method or Special Method of Python
def __init__():
In that, we have some Tkinter related stuff.
Second Method of Login Class:
def validate():
This method will Validate Login and match the Password.
It arranges username — for finding the user in the database in a tuple
Then arranges input data in a tuple
def validate(self):
data = (self.username,)
inputData = (self.username, self.password,)
After That, We check to call a method from Database Class to ValidateData or check Data.
try:
if (db.validateData(data, inputData)):
messagebox.showinfo(“Successful”, “Login Was Successful”)
else:
messagebox.showerror(“Error”, “Wrong Credentials”)
If you look carefully, We Started a Try — Except Block.
We check if we have some return value and then show the user “They Have Successfully Logged In”
Else we show the error
Except Block —
except IndexError:
messagebox.showerror(“Error”, “Wrong Credentials”)
If We Not found them in the Database, then SQLite will throw **IndexError, **which we can tackle easily...
After that, we defined a Register Class — Which will do the same but it adds it the to database and with
self.salt = bcrypt.gensalt()
self.hashed = bcrypt.hashpw(self.password.encode(), self.salt)
It is used to encrypt Password.
database.py
# Importing Important Libraries
import sqlite3
import bcrypt
class Database:
‘’’
Database Class for sqlite3
:params conn — sqlite3Connection
:params curr — cursor
‘’’
def __init__(self):
try:
self.conn = sqlite3.connect(“test.db”)
print(“Successfully Opened Database”)
self.curr = self.conn.cursor()
except:
print(“Failed”)
def createTable(self):
‘’’
Method for Creating Table in Database
‘’’
create_table = ‘’’
CREATE TABLE IF NOT EXISTS cred(
id Integer PRIMARY KEY AUTOINCREMENT,
username TEXT NOT NULL,
password TEXT NOT NULL
);
‘’’
self.curr.execute(create_table)
self.conn.commit()
def insertData(self, data):
‘’’
Method for Inserting Data in Table in Database
‘’’
insert_data = “””
INSERT INTO cred(username, password)
VALUES(?, ?);
“””
self.curr.execute(insert_data, data)
self.conn.commit()
def searchData(self, data):
‘’’
Method for Searching Data in Table in Database
‘’’
search_data = ‘’’
SELECT * FROM cred WHERE username = (?);
‘’’
self.curr.execute(search_data, data)
rows = self.curr.fetchall()
if rows == []:
return 1
return 0
def validateData(self, data, inputData):
‘’’
Method for Validating Data Table in Database
‘’’
print(data)
print(inputData)
validate_data = “””
SELECT * FROM cred WHERE username = (?);
“””
self.curr.execute(validate_data, data)
row = self.curr.fetchall()
if row[0][1] == inputData[0]:
return row[0][2] == bcrypt.hashpw(inputData[1].encode(), row[0][2])
These are some bunch of SQL Commands executed with Python.
Thanks for Your Time.
Stay Home, Stay Safe
Satyam Kulkarni
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