Initial commit: NFC Actions Windows tray application
Implement PC/SC-based NFC card reader monitoring application with WPF UI. Features include: - System tray integration with single-click to open main window - Dynamic reader detection and management with enable/disable per reader - NDEF payload extraction supporting Type 2 and Type 4 tags - Auto-detection of block sizes (4-byte vs 16-byte) for different reader types - Configurable actions: copy to clipboard, launch URLs, keyboard input simulation - URI record type detection - only launches browser for actual URI records - Real-time activity logging with color-coded levels (Debug, Info, Warning, Error) - File-based debug logging for troubleshooting - Settings persistence between sessions - Dangerous Things branding with custom icons and clickable logo 🤖 Generated with [Claude Code](https://claude.com/claude-code) Co-Authored-By: Claude <noreply@anthropic.com>
This commit is contained in:
311
NfcActions/Services/NdefParser.cs
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311
NfcActions/Services/NdefParser.cs
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using System;
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using System.Text;
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namespace NfcActions.Services;
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public class NdefRecord
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{
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public string Payload { get; set; } = string.Empty;
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public bool IsUri { get; set; }
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}
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public static class NdefParser
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{
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/// <summary>
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/// Extracts the first NDEF payload from raw card data.
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/// Returns the payload as a string, or null if no valid NDEF message found.
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/// </summary>
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public static string? ExtractFirstPayload(byte[] data)
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{
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var record = ExtractFirstRecord(data);
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return record?.Payload;
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}
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/// <summary>
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/// Extracts the first NDEF record from raw card data with type information.
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/// Returns an NdefRecord object, or null if no valid NDEF message found.
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/// </summary>
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public static NdefRecord? ExtractFirstRecord(byte[] data)
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{
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if (data == null || data.Length < 3)
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return null;
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try
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{
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int position = 0;
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// Look for NDEF TLV (Type-Length-Value) structure
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// We're looking for TLV type 0x03 which indicates NDEF Message
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while (position < data.Length - 2)
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{
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byte tlvType = data[position];
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if (tlvType == 0x00) // NULL TLV, skip
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{
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position++;
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continue;
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}
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if (tlvType == 0xFE) // Terminator TLV
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{
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break;
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}
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position++; // Move to length byte
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if (position >= data.Length)
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break;
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int length;
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if (data[position] == 0xFF) // 3-byte length format
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{
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if (position + 2 >= data.Length)
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break;
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length = (data[position + 1] << 8) | data[position + 2];
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position += 3;
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}
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else
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{
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length = data[position];
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position++;
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}
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if (tlvType == 0x03) // NDEF Message TLV
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{
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if (position + length > data.Length)
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break;
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// Parse NDEF message
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var record = ParseNdefMessage(data, position, length);
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if (record != null)
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return record;
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}
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position += length;
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}
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// If we didn't find TLV structure, try to parse as raw NDEF message
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return ParseNdefMessage(data, 0, data.Length);
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}
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catch
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{
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return null;
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}
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}
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private static NdefRecord? ParseNdefMessage(byte[] data, int offset, int length)
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{
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if (offset + length > data.Length || length < 3)
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return null;
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int position = offset;
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int endPosition = offset + length;
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while (position < endPosition)
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{
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if (position >= data.Length)
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break;
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byte header = data[position];
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position++;
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bool mb = (header & 0x80) != 0; // Message Begin
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bool me = (header & 0x40) != 0; // Message End
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bool cf = (header & 0x20) != 0; // Chunk Flag
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bool sr = (header & 0x10) != 0; // Short Record
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bool il = (header & 0x08) != 0; // ID Length present
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byte tnf = (byte)(header & 0x07); // Type Name Format
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if (position >= endPosition)
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break;
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int typeLength = data[position];
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position++;
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int typePosition = 0; // Track where type field starts
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if (position >= endPosition)
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break;
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int payloadLength;
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if (sr) // Short record - 1 byte payload length
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{
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payloadLength = data[position];
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position++;
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}
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else // Normal record - 4 byte payload length
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{
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if (position + 3 >= endPosition)
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break;
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payloadLength = (data[position] << 24) |
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(data[position + 1] << 16) |
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(data[position + 2] << 8) |
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data[position + 3];
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position += 4;
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}
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int idLength = 0;
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if (il)
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{
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if (position >= endPosition)
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break;
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idLength = data[position];
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position++;
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}
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// Remember type position before skipping
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typePosition = position;
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// Read type field to check if it's a URI record
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byte[]? typeField = null;
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if (typeLength > 0 && position + typeLength <= endPosition)
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{
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typeField = new byte[typeLength];
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Array.Copy(data, position, typeField, 0, typeLength);
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}
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// Skip type
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position += typeLength;
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// Skip ID
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position += idLength;
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if (position + payloadLength > endPosition)
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break;
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// Extract payload
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if (payloadLength > 0)
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{
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byte[] payload = new byte[payloadLength];
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Array.Copy(data, position, payload, 0, payloadLength);
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// Determine if this is a URI record
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bool isUri = IsUriRecord(tnf, typeField, payload);
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// Decode payload
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string payloadText = DecodeTextPayload(payload);
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return new NdefRecord
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{
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Payload = payloadText,
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IsUri = isUri
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};
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}
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position += payloadLength;
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// If this was the first record, return what we found (or null)
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break;
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}
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return null;
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}
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private static bool IsUriRecord(byte tnf, byte[]? typeField, byte[] payload)
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{
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// TNF Well-Known (0x01) with type "U" is a URI record
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if (tnf == 0x01 && typeField != null && typeField.Length == 1 && typeField[0] == 0x55) // 'U'
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{
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return true;
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}
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// TNF Absolute URI (0x03)
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if (tnf == 0x03)
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{
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return true;
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}
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// Check if payload starts with URI identifier code (0x00-0x23)
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if (payload.Length > 0 && payload[0] <= 0x23)
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{
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string prefix = GetUriPrefix(payload[0]);
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// If we have a recognized URI prefix, it's likely a URI
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if (!string.IsNullOrEmpty(prefix) || payload[0] == 0x00)
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{
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return true;
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}
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}
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return false;
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}
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private static string DecodeTextPayload(byte[] payload)
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{
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if (payload.Length == 0)
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return string.Empty;
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// Check if first byte indicates URI identifier code
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if (payload[0] <= 0x23) // URI identifier codes range from 0x00 to 0x23
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{
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string prefix = GetUriPrefix(payload[0]);
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string uri = Encoding.UTF8.GetString(payload, 1, payload.Length - 1);
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return prefix + uri;
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}
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// Check if it's a text record (first byte is status byte)
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if (payload.Length > 1)
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{
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byte statusByte = payload[0];
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bool isUtf16 = (statusByte & 0x80) != 0;
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int languageCodeLength = statusByte & 0x3F;
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if (languageCodeLength < payload.Length)
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{
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int textStart = 1 + languageCodeLength;
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if (textStart < payload.Length)
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{
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var encoding = isUtf16 ? Encoding.Unicode : Encoding.UTF8;
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return encoding.GetString(payload, textStart, payload.Length - textStart);
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}
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}
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}
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// Default: try UTF8 decoding of entire payload
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return Encoding.UTF8.GetString(payload);
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}
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private static string GetUriPrefix(byte code)
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{
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return code switch
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{
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0x00 => "",
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0x01 => "http://www.",
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0x02 => "https://www.",
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0x03 => "http://",
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0x04 => "https://",
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0x05 => "tel:",
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0x06 => "mailto:",
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0x07 => "ftp://anonymous:anonymous@",
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0x08 => "ftp://ftp.",
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0x09 => "ftps://",
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0x0A => "sftp://",
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0x0B => "smb://",
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0x0C => "nfs://",
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0x0D => "ftp://",
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0x0E => "dav://",
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0x0F => "news:",
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0x10 => "telnet://",
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0x11 => "imap:",
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0x12 => "rtsp://",
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0x13 => "urn:",
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0x14 => "pop:",
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0x15 => "sip:",
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0x16 => "sips:",
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0x17 => "tftp:",
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0x18 => "btspp://",
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0x19 => "btl2cap://",
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0x1A => "btgoep://",
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0x1B => "tcpobex://",
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0x1C => "irdaobex://",
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0x1D => "file://",
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0x1E => "urn:epc:id:",
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0x1F => "urn:epc:tag:",
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0x20 => "urn:epc:pat:",
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0x21 => "urn:epc:raw:",
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0x22 => "urn:epc:",
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0x23 => "urn:nfc:",
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_ => ""
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};
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}
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}
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