Welcome to the Barcode Scanner App codelab! In this tutorial, you will learn how to:

• Install the app via terminal
• Verify the service is running
• Simulate external connections using Postman
• Send commands and check responses
• Explore two use cases: a successful scan and an aborted scan

• Castles S1U2 device is required for this codelab
• The device must be connected to a network (via WiFi)
• Barcode Scanner app (only available from the SmartPOS Store)
• Postman installed on your computer (Download Postman)

1. Open the SmartPOS Store client app on your device (usually found in the terminal menu).
2. Search for "Barcode Scanner" in the SmartPOS Store.

3. Install the application directly from the SmartPOS Store.

Note: The Barcode Scanner app is only available as an official release through the SmartPOS Store.

4. Confirm installation on your device.

1. After installation, check the status bar for the Barcode Scanner app service icon.

2. If the icon is not visible, open the app from the launcher menu.

3. The main activity will display the service status and WebSocket connection info.

4. Verify that the service icon (camera icon) is present in the status bar.

5. If an external connection has been established, the notification center will display the connection status.

6. The service is now running.

Warning: The WebSocket server must be running for external connections to work.

1. Open Postman on your computer.
2. Create a new collection.

3. Create a new WebSocket request.

4. Enter the WebSocket URL in Postman:

• a. Enter the device IP and port in the URL field:
• b. To find the device IP, check the main activity screen in the app:

5. Click Connect to establish the WebSocket connection.

6. You should see a successful connection message.

Note: Ensure your computer and device are on the same network.

1. In Postman, send the following command as a simple string (not JSON):

   readScannerData
   

• a. Enter the command in the message field:
• b. Click the Send button:

2. Confirm the command has been sent successfully in Postman.

3. The app will initiate a scan.

Note: Present a barcode or QR code at the bottom of the device so the reader can scan it.

4. You should receive a response in Postman with the scanned data:

   {
     status: "success",
     data: "<scanned-barcode-data>"
   }
   

   

1. In Postman, send the following command as a simple string (not JSON):

   readScannerData
   

• a. Enter the command in the message field:
• b. Click the Send button:

2. Confirm the command has been sent successfully in Postman.

3. Before scanning a barcode, send the cancelRead command as a simple string (not JSON):

   cancelRead
   

• a. Enter the command in the message field:
• b. Click the Send button:

4. Confirm the cancel command has been sent successfully in Postman.

5. The scan operation will be aborted. You should receive a response indicating the cancellation:

   {
     "status": "success",
     "data": "Read operation canceled"
   }
   

   
6. You should also receive a response to the initial readScannerData command:

   {
     "status": "error",
     "data": "No data read from scanner"
   }
   

   

Note: This demonstrates how to abort a scan operation from an external client.

You have learned how to:

• Install and verify the Barcode Scanner app
• Connect and interact with the app using Postman
• Send commands and handle responses for both successful and aborted scan operations