main.py

# Import necessary modules from Flask for creating the API, handling requests, and JSON formatting.
from flask import Flask, request, jsonify
import sqlite3  # Import SQLite3 for database operations.



app = Flask(__name__)        # Create an instance of the Flask class.


@app.route('/', methods=['GET'])
def main():
    return jsonify("Hello World")



def createTables():  # Define a function to create a user table if it doesn't already exist in the database.

    conn = sqlite3.connect("my_user.db")      # Connect to the SQLite database.
    cursor = conn.cursor()    # Create a cursor object to execute SQL queries.

    # Execute a SQL query to create the User table with specified columns if it doesn't exist.
    cursor.execute('''
        CREATE TABLE IF NOT EXISTS User (
            Id INTEGER PRIMARY KEY AUTOINCREMENT,
            Name VARCHAR(255),
            Password VARCHAR(255),
            Address VARCHAR(255),
            PinCode VARCHAR(255),
            Email VARCHAR(255),
            Phone VARCHAR(255)
        )
    ''')
    # Commit the changes to the database.
    conn.commit()
    # Close the database connection.
    conn.close()




# Define a route for adding a new user via a POST request.
@app.route('/addUser', methods=['POST'])
def add_user():
    try:
        # Extract form data from the request.
        name = request.form['Name']
        password = request.form['Password']
        address = request.form['Address']
        pincode = request.form['PinCode']
        email = request.form['Email']
        phone = request.form['Phone']

        # Connect to the SQLite database.
        conn = sqlite3.connect("my_user.db")
        # Create a cursor object to execute SQL queries.
        cursor = conn.cursor()
        # Execute an SQL query to insert user data into the User table.
        cursor.execute("INSERT INTO User (Name, Password, Address, PinCode, Email, Phone) VALUES (?, ?, ?, ?, ?, ?)",
                       (name, password, address, pincode, email, phone))
        # Commit the changes to the database.
        conn.commit()
        # Close the database connection.
        conn.close()

        # Return a JSON response indicating successful user addition.
        return jsonify({"message": "User added successfully"}), 201
    except Exception as e:
        # Return a JSON response indicating any errors that occurred during user addition.
        return jsonify({"error": str(e)}), 400






# Define a route for fetching and displaying all users via a GET request.
@app.route('/showUsers', methods=['GET'])
def show_users():
    try:
        # Connect to the SQLite database.
        conn = sqlite3.connect("my_user.db")
        # Create a cursor object to execute SQL queries.
        cursor = conn.cursor()
        # Execute an SQL query to retrieve all users from the User table.
        cursor.execute("SELECT * FROM User")
        # Fetch all user records from the cursor.
        users = cursor.fetchall()
        # Close the database connection.
        conn.close()

        # Initialize an empty list to store user data dictionaries.
        user_list = []
        # Iterate through each user record fetched from the database.
        for user in users:
            # Create a dictionary representing user data with appropriate keys and values.
            user_dict = {
                "Id": user[0],
                "Name": user[1],
                "Password": user[2],
                "Address": user[3],
                "PinCode": user[4],
                "Email": user[5],
                "Phone": user[6]
            }
            # Append the user dictionary to the user list.
            user_list.append(user_dict)

        # Return a JSON response containing the list of user data.
        return jsonify(user_list), 200
    except Exception as e:
        # Return a JSON response indicating any errors that occurred during user retrieval.
        return jsonify({"error": str(e)}), 400







# Define a route for updating user information via a PUT request.
@app.route('/updateUser/<int:user_id>', methods=['PUT'])
def update_user(user_id):
    try:
        # Connect to the SQLite database.
        conn = sqlite3.connect("my_user.db")
        # Create a cursor object to execute SQL queries.
        cursor = conn.cursor()

        # Prepare the SET part of the SQL query dynamically based on form data.
        set_values = []
        # Iterate through form data items.
        for key, value in request.form.items():
            # Check if the key is a valid field name in the User table.
            if key in ['Name', 'Password', 'Address', 'PinCode', 'Email', 'Phone']:
                # Append a string representing the key-value pair to the set_values list.
                set_values.append(f"{key}='{value}'")
        # Join the set_values list elements with commas to create the SET clause of the SQL query.
        set_clause = ", ".join(set_values)

        # Execute the SQL query to update user information.
        cursor.execute(f"UPDATE User SET {set_clause} WHERE Id=?", (user_id,))
        # Commit the changes to the database.
        conn.commit()
        # Close the database connection.
        conn.close()

        # Return a JSON response indicating successful user update.
        return jsonify({"message": "User updated successfully"}), 200
    except Exception as e:
        # Return a JSON response indicating any errors that occurred during user update.
        return jsonify({"error": str(e)}), 400






# Define a route for deleting a user via a DELETE request.
@app.route('/deleteUser/<int:user_id>', methods=['DELETE'])
def delete_user(user_id):
    try:
        # Connect to the SQLite database.
        conn = sqlite3.connect("my_user.db")
        # Create a cursor object to execute SQL queries.
        cursor = conn.cursor()
        # Execute an SQL query to delete a user with the specified user_id.
        cursor.execute("DELETE FROM User WHERE Id=?", (user_id,))
        # Commit the changes to the database.
        conn.commit()
        # Close the database connection.
        conn.close()

        # Return a JSON response indicating successful user deletion.
        return jsonify({"message": "User deleted successfully"}), 200
    except Exception as e:
        # Return a JSON response indicating any errors that occurred during user deletion.
        return jsonify({"error": str(e)}), 400





# Start the Flask application.
if __name__ == "__main__":
    # Call the createTables function to ensure the User table exists in the database.
    createTables()
    # Run the Flask application in debug mode.
    app.run(debug=True)