QR Code Scanner and Validator

This project is a simple web application built with Streamlit that allows you to:

• Generate QR codes from text input.
• Scan and decode QR codes from uploaded images.
• Validate the content of decoded QR codes based on a predefined URL pattern.

Prerequisites

• Python 3.7+
• A Google Colab environment (for easy setup)
• An ngrok account and API key (for exposing the application via a public URL)

Libraries Used

• pyqrcode: For generating QR codes.
• pyzbar: For decoding QR codes from images.
• pillow: For image processing.
• streamlit: For creating the web interface.
• pyngrok: For creating an ngrok tunnel to make the app publicly accessible.
• pypng: To make sure that it saves images

Setup and Usage in Google Colab

1. Clone/Copy the Code:

   • Create a folder in your Google Drive (e.g., QR_script).
   • Upload the main.py file to that folder.

2. Google Colab Setup:

   • Create a new Google Colab notebook.

   • Copy and paste the following code blocks into separate cells in the notebook:

     Block 1: Mount Google Drive (Optional)

     from google.colab import drive
     drive.mount('/content/drive')

     • Note: This block is only necessary if you plan to load or save QR code images from/to your Google Drive. If you only intend to work with uploaded files, you can skip this step.

     Block 2: Install Dependencies

     !pip install pyqrcode pyzbar pillow streamlit pyngrok pypng

     • This cell installs all the necessary Python libraries. Make sure to run this cell first.

     Block 3: ZBar Library Installation (Conditional)

     try:
         from pyzbar.pyzbar import decode
         print("pyzbar imported successfully (ZBar library likely already installed).")
     except ImportError:
         print("ZBar library not found. Installing...")
         !apt-get install -y zbar-tools
         import os
         os.kill(os.getpid(), 9)  # Restart the runtime after installing ZBar

     • This block attempts to import pyzbar. If it fails, it installs the ZBar library using apt-get and restarts the Colab runtime.

     Block 4: Ngrok Setup and Streamlit Execution

     from pyngrok import ngrok
     
     ngrok.set_auth_token("YOUR_NGROK_AUTHTOKEN")  # Replace with your ngrok API key
     
     tunnel = ngrok.connect(addr="8501", proto="http", bind_tls=True)  # Streamlit's default port
     
     public_url = tunnel.public_url
     print(f"Public URL: {public_url}")
     
     !streamlit run --server.port 8501 /content/drive/MyDrive/QR_script/main.py &

     • Important: Replace "YOUR_NGROK_AUTHTOKEN" with your actual ngrok API key.
     • This block sets up the ngrok tunnel, retrieves the public URL, and starts the Streamlit server, pointing to your main.py script in Google Drive.

3. Run the Colab Notebook:

   • Execute the cells in the notebook one by one, in order.
   • After the last cell executes, you will see a "Public URL" printed in the output.
   • Click on the URL to access the web application in your browser.

How to Use the Web Application

1. Generate QR Code:

   • Enter the text you want to encode into the "Enter data to encode into the QR code:" text input field.
   • Click the "Generate QR Code" button.
   • The generated QR code will be displayed. You can download the QR code image using the "Download QR Code" button.

2. Scan and Validate QR Code:

   • Upload a QR code image using the "Upload a QR code image" file uploader.
   • The application will decode the QR code. If the decoding is successful:
     • The decoded data will be displayed.
     • The application will validate the decoded data against the URL pattern https://www.example.com/....
     • A message indicating whether the validation was successful or not will be displayed.
     • You can download the decoded data as a text file using the "Save and Download Base64 Text File" button.