Add USB card reader authentication for edit feature

- Implemented CardReader class to read data from USB card readers
- Added CardSwipePopup with 5-second timeout and visual feedback
- Card data is captured and included in edit metadata
- Card data sent to server when edited images are uploaded
- Added evdev dependency for USB input device handling
- Fallback mode when evdev not available (for development)
- Created test utility (test_card_reader.py) for card reader testing
- Added comprehensive documentation (CARD_READER_AUTHENTICATION.md)
- Added access-card.png icon for authentication popup
- Edit interface requires card swipe or times out after 5 seconds
This commit is contained in:
2025-12-08 14:05:04 +02:00
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# USB Card Reader Authentication
This document describes the USB card reader authentication feature for the Kiwy Signage Player.
## Overview
The player now supports user authentication via USB card readers when accessing the edit/drawing interface. When a user clicks the edit button (pencil icon), they must swipe their card to authenticate before being allowed to edit the image.
## How It Works
1. **Edit Button Click**: User clicks the pencil icon to edit the current image
2. **Validation Checks**:
- Verify current media is an image (not video)
- Check if editing is allowed for this media (`edit_on_player` permission from server)
3. **Card Reader Prompt**:
- Display "Please swipe your card..." message
- Wait for card swipe (5 second timeout)
- Read card data from USB card reader
- Store the card data (no validation required)
4. **Open Edit Interface**: Edit interface opens with card data stored
5. **Save & Upload**: When user saves the edited image:
- Card data is included in the metadata JSON
- Both image and metadata (with card data) are uploaded to server
- Server receives `user_card_data` field for tracking who edited the image
## Card Reader Setup
### Hardware Requirements
- USB card reader (HID/keyboard emulation type)
- Compatible cards (magnetic stripe or RFID depending on reader)
### Software Requirements
The player requires the `evdev` Python library to interface with USB input devices:
```bash
# Install via apt (recommended for Raspberry Pi)
sudo apt-get install python3-evdev
# Or via pip
pip3 install evdev
```
### Fallback Mode
If `evdev` is not available, the player will:
- Log a warning message
- Use a default card value (`DEFAULT_USER_12345`) for testing
- This allows development and testing without hardware
## Card Data Storage
The card data is captured as a raw string and stored without validation or mapping:
- **No preprocessing**: Card data is stored exactly as received from the reader
- **Format**: Whatever the card reader sends (typically numeric or alphanumeric)
- **Sent to server**: Raw card data is included in the `user_card_data` field of the metadata JSON
- **Server-side processing**: The server can validate, map, or process the card data as needed
### Metadata JSON Format
When an image is saved, the metadata includes:
```json
{
"time_of_modification": "2025-12-08T10:30:00",
"original_name": "image.jpg",
"new_name": "image_e_v1.jpg",
"original_path": "/path/to/image.jpg",
"version": 1,
"user_card_data": "123456789"
}
```
If no card is swiped (timeout), `user_card_data` will be `null`.
## Testing the Card Reader
A test utility is provided to verify card reader functionality:
```bash
cd /home/pi/Desktop/Kiwy-Signage/working_files
python3 test_card_reader.py
```
The test tool will:
1. List all available input devices
2. Auto-detect the card reader (or let you select manually)
3. Listen for card swipes and display the data received
4. Show how the data will be processed
### Test Output Example
```
✓ Card data received: '123456789'
Length: 9 characters
Processed ID: card_123456789
```
## Implementation Details
### Main Components
1. **CardReader Class** (`main.py`)
- Handles USB device detection
- Reads input events from card reader
- Provides async callback interface
- Includes timeout handling (5 seconds)
2. **Card Read Flow** (`show_edit_interface()` method)
- Validates media type and permissions
- Initiates card read
- Stores raw card data
- Opens edit popup
3. **Metadata Creation** (`_save_metadata()` method)
- Includes card data in metadata JSON
- No processing or validation of card data
- Sent to server as-is
### Card Data Format
Card readers typically send data as keyboard input:
- Each character is sent as a key press event
- Data ends with an ENTER key press
- Reader format: `[CARD_DATA][ENTER]`
The CardReader class:
- Captures key press events
- Builds the card data string character by character
- Completes reading when ENTER is detected
- Returns the complete card data to the callback
### Security Considerations
1. **Server-Side Validation**: Card validation should be implemented on the server
2. **Timeout**: 5-second timeout prevents infinite waiting for card swipe
3. **Logging**: All card reads are logged with the raw card data
4. **Permissions**: Edit permission must be enabled on the server (`edit_on_player`)
5. **Raw Data**: Card data is sent as-is; server is responsible for validation and authorization
## Troubleshooting
### Card Reader Not Detected
- Check USB connection
- Run `ls /dev/input/` to see available devices
- Run the test script to verify detection
- Check `evdev` is installed: `python3 -c "import evdev"`
### Card Swipes Not Recognized
- Verify card reader sends keyboard events
- Test with the `test_card_reader.py` utility
- Check card format is compatible with reader
- Ensure card is swiped smoothly at proper speed
### Card Data Not Captured
- Check card data format in logs
- Enable debug logging to see raw card data
- Test in fallback mode (without evdev) to isolate hardware issues
- Verify card swipe completes within 5-second timeout
### Permission Denied Errors
- User may need to be in the `input` group:
```bash
sudo usermod -a -G input $USER
```
- Reboot after adding user to group
## Future Enhancements
Potential improvements for the card reader system:
1. **Server Validation**: Server validates cards against database and returns authorization
2. **Card Enrollment**: Server-side UI for registering new cards
3. **Multiple Card Types**: Support for different card formats (barcode, RFID, magnetic)
4. **Client-side Validation**: Add optional local card validation before opening edit
5. **Audit Trail**: Server tracks all card usage with timestamps
6. **RFID Support**: Test and optimize for RFID readers
7. **Barcode Scanners**: Support USB barcode scanners as alternative
8. **Retry Logic**: Allow re-swipe if card read fails
## Related Files
- `/src/main.py` - Main implementation (CardReader class, authentication flow)
- `/src/edit_drowing.py` - Drawing/editing interface (uses authenticated user)
- `/working_files/test_card_reader.py` - Card reader test utility
- `/requirements.txt` - Dependencies (includes evdev)

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#!/usr/bin/env python3
"""
Test script for USB card reader functionality
"""
import evdev
from evdev import InputDevice, categorize, ecodes
import time
def list_input_devices():
"""List all available input devices"""
print("\n=== Available Input Devices ===")
devices = [evdev.InputDevice(path) for path in evdev.list_devices()]
for i, device in enumerate(devices):
print(f"\n[{i}] {device.path}")
print(f" Name: {device.name}")
print(f" Phys: {device.phys}")
capabilities = device.capabilities()
if ecodes.EV_KEY in capabilities:
print(f" Type: Keyboard/HID Input Device")
return devices
def test_card_reader(device_index=None):
"""Test reading from a card reader device"""
devices = [evdev.InputDevice(path) for path in evdev.list_devices()]
if device_index is not None:
if device_index >= len(devices):
print(f"Error: Device index {device_index} out of range")
return
device = devices[device_index]
else:
# Try to find a card reader automatically
device = None
for dev in devices:
if 'keyboard' in dev.name.lower() or 'card' in dev.name.lower() or 'reader' in dev.name.lower():
device = dev
print(f"Found potential card reader: {dev.name}")
break
if not device and devices:
# Use first keyboard device
for dev in devices:
capabilities = dev.capabilities()
if ecodes.EV_KEY in capabilities:
device = dev
print(f"Using keyboard device: {dev.name}")
break
if not device:
print("No suitable input device found!")
return
print(f"\n=== Testing Card Reader ===")
print(f"Device: {device.name}")
print(f"Path: {device.path}")
print("\nSwipe your card now (press Ctrl+C to exit)...\n")
card_data = ""
try:
for event in device.read_loop():
if event.type == ecodes.EV_KEY:
key_event = categorize(event)
if key_event.keystate == 1: # Key down
key_code = key_event.keycode
# Handle Enter key (card read complete)
if key_code == 'KEY_ENTER':
print(f"\n✓ Card data received: '{card_data}'")
print(f" Length: {len(card_data)} characters")
print(f" Processed ID: card_{card_data.strip().upper()}")
print("\nReady for next card swipe...")
card_data = ""
# Build card data string
elif key_code.startswith('KEY_'):
char = key_code.replace('KEY_', '')
if len(char) == 1: # Single character
card_data += char
print(f"Reading: {card_data}", end='\r', flush=True)
elif char.isdigit(): # Handle numeric keys
card_data += char
print(f"Reading: {card_data}", end='\r', flush=True)
except KeyboardInterrupt:
print("\n\nTest stopped by user")
except Exception as e:
print(f"\nError: {e}")
if __name__ == "__main__":
print("USB Card Reader Test Tool")
print("=" * 50)
devices = list_input_devices()
if not devices:
print("\nNo input devices found!")
exit(1)
print("\n" + "=" * 50)
choice = input("\nEnter device number to test (or press Enter for auto-detect): ").strip()
if choice:
try:
device_index = int(choice)
test_card_reader(device_index)
except ValueError:
print("Invalid device number!")
else:
test_card_reader()