Final Project: Enhancing Python Applications with Defensive Programming

BSCS 3A

Submitted by:

• Eugene P. Aquilino
• Mary France B. San Andres

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1. Project Overview

This project demonstrates how to enhance a basic Python application, specifically a Phone Number Tracker, with robust defensive programming techniques.

1.1 Original Project Description

The original project was a Phone Number Tracker application built using Python and Tkinter for the Graphical User Interface (GUI). Its core function was to accept a phone number as input and then determine the associated country.

1.2 Rationale for Project Choice

We selected this project to illustrate the practical application of:

• GUI Integration: Combining front-end user interaction with backend logic.
• Data Processing: Handling user input and processing it in real-time.
• External Libraries: Utilizing external resources (like pycountry and phone_iso3166) for enhanced functionality.

1.3 Summary of Improvements and Enhancements

Our enhancements focused on improving the application's reliability, user-friendliness, and code quality:

• Robust Input Validation: Implemented stricter checks to ensure valid phone number formats.
• Comprehensive Error Handling: Added try-except blocks to gracefully handle potential errors and provide informative feedback to the user.
• Enhanced User Interface: Refined the GUI layout and added a "Clear" button for better usability.
• Detailed Error Messages: Improved the clarity of error messages to help users understand and resolve issues.

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2. Installation and Setup Guide

Follow these steps to set up the development environment and run the enhanced application.

2.1 Setting Up the Development Environment

1. Clone the Repository:

   git clone [repository_url] 

   (Replace [repository_url] with the actual URL of your project repository).

2. Navigate to the Project Directory:

   cd [project_directory_name]

3. Install Dependencies:

   pip install -r requirements.txt

2.2 Dependencies and Requirements

• Python 3.x
• Tkinter: (Usually comes bundled with Python)
• pycountry: pip install pycountry
• phone_iso3166: pip install phone-iso3166

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3. User Manual

Learn how to use the enhanced Phone Number Tracker application.

3.1 How to Use the Application

1. Save the Code: Save the Python code as a file named app.py (or any .py file).
2. Run the Application: Execute the script from your terminal:

   python app.py

3. Enter a Phone Number: Input a phone number into the entry field.
4. Track the Country: Click the "Track Country" button.
5. View Results: The application will display the country associated with the phone number. If the country cannot be determined, it will display "Country is Unknown."

3.2 New Features and Functionalities

• Clear Button: A new "Clear" button resets the input field, making it easier to enter new numbers.
• Enhanced Error Handling: The application is more resilient to invalid inputs and provides more informative error messages.

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4. Technical Documentation

This section provides in-depth information about the technical aspects of the project.

4.1 Architectural Changes

-The overall architecture of the application changed the font size, color of a simple GUI application with a main window, entry field, button, and label.

4.2 New Classes, Methods, and Functions

• No New Classes: The project's structure remains similar to the original.
• Enhanced Methods: The track_location and clear_fields methods were improved for better functionality and error handling.

4.3 Defensive Programming Techniques Implemented

• Input Validation: We implemented strict checks to ensure the entered phone number consists of valid digits only.
• Exception Handling: try-except blocks are used to catch potential errors during country information retrieval, preventing crashes and providing user-friendly error messages.

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5. Code Review and Refactoring

This section details the code improvements made during the project.

5.1 Major Code Changes

• Improved Input Validation: The track_location method now includes more robust validation of the phone number input.
• Enhanced Error Messages: Error messages are more descriptive and user-friendly.
• Clear Button Functionality: Added the functionality for the "Clear" button to reset the input field.

5.2 Justification for Refactoring Decisions

Refactoring was essential to:

• Improve Code Readability: Make the code easier to understand and maintain.
• Enhance Maintainability: Simplify future modifications and debugging.
• Improve User Experience: Provide a smoother and more intuitive interaction for the user.

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6. Testing Documentation

This section outlines the testing strategy and results.

6.1 Overview of Testing Strategy

We employed manual testing to verify the application's functionality and the effectiveness of the enhancements.

6.2 Test Cases and Results

Test Case	Input	Expected Result	Actual Result	Status
Valid Phone Number	+15551234567	Country: United States	Country: United States	Pass
Invalid Phone Number	abc	Error: Invalid phone number format	Error: Invalid phone number format	Pass
Clear Button	(Any input)	Input field is cleared	Input field is cleared	Pass
Country not found	+9999999999	Country is Unknown	Country is Unknown	Pass

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7. Challenges and Solutions

Here, we discuss the challenges faced and how we overcame them.

7.1 Difficulties Encountered

• Handling Invalid Phone Number Inputs: Ensuring the application gracefully handles various invalid input formats.
• Managing Exceptions: Dealing with potential errors during country information retrieval from external libraries.

7.2 How Challenges Were Addressed

• Input Validation: Implemented rigorous input validation using conditional statements to check for valid digits before processing.
• Exception Handling: Added try-except blocks to catch exceptions, preventing the application from crashing and providing informative error messages to the user.

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8. Future Improvements

We propose the following enhancements for future development:

• Support for International Formats: Extend the application to handle a wider range of international phone number formats.
• Robust Testing Framework: Implement automated unit and integration tests using a framework like unittest or pytest.
• GUI Enhancements: Improve the user interface with:
  • More advanced styling (e.g., using themed Tkinter widgets).
  • Additional features (e.g., displaying the country flag, a map).

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9. References and Resources

• Original Project:
• Alternative Project: https://github.com/Kalebu/Python-phonenumber-tracker-App.git

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