3D-Druck/Filaman
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases 184 Wiki Activity

feat: enhance NDEF decoding with detailed validation and debugging output

Browse Source
This commit is contained in:
Manuel Weiser
2025-08-29 09:46:08 +02:00
parent d897817020
commit f1cdd3f41d
1 changed files with 135 additions and 16 deletions
Download Patch File Download Diff File Expand all files Collapse all files

151
src/nfc.cpp
View File

@@ -206,62 +206,169 @@ uint8_t ntag2xx_WriteNDEF(const char *payload) {
bool decodeNdefAndReturnJson(const byte* encodedMessage, String uidString) {
oledShowProgressBar(1, octoEnabled?5:4, "Reading", "Decoding data");
// Check for NDEF TLV (Type-Length-Value) structure
if (encodedMessage[0] != 0x03) {
Serial.println("Not a valid NDEF message (missing TLV tag 0x03)");
// Debug: Print first 32 bytes of the raw data
Serial.println("Raw NDEF data (first 32 bytes):");
for (int i = 0; i < 32; i++) {
if (encodedMessage[i] < 0x10) Serial.print("0");
Serial.print(encodedMessage[i], HEX);
Serial.print(" ");
if ((i + 1) % 16 == 0) Serial.println();
}
Serial.println();
// Look for the NDEF TLV structure starting from the beginning
int tlvOffset = 0;
bool foundNdefTlv = false;
// Search for NDEF TLV (0x03) in the first few bytes
for (int i = 0; i < 16; i++) {
if (encodedMessage[i] == 0x03) {
tlvOffset = i;
foundNdefTlv = true;
Serial.print("Found NDEF TLV at offset: ");
Serial.println(tlvOffset);
break;
}
}
if (!foundNdefTlv) {
Serial.println("No NDEF TLV found in tag data");
return false;
}
// Get the total NDEF message length from TLV
byte ndefMessageLength = encodedMessage[1];
// Get the NDEF message length from TLV
uint16_t ndefMessageLength = 0;
int ndefRecordOffset = 0;
// Skip TLV header (2 bytes) to get to NDEF record
const byte* ndefRecord = &encodedMessage[2];
if (encodedMessage[tlvOffset + 1] == 0xFF) {
// Extended length format: next 2 bytes contain the actual length
ndefMessageLength = (encodedMessage[tlvOffset + 2] << 8) | encodedMessage[tlvOffset + 3];
ndefRecordOffset = tlvOffset + 4; // Skip TLV tag + 0xFF + 2 length bytes
Serial.print("NDEF Message Length (extended): ");
} else {
// Standard length format: single byte contains the length
ndefMessageLength = encodedMessage[tlvOffset + 1];
ndefRecordOffset = tlvOffset + 2; // Skip TLV tag + 1 length byte
Serial.print("NDEF Message Length (standard): ");
}
Serial.println(ndefMessageLength);
// Get pointer to NDEF record
const byte* ndefRecord = &encodedMessage[ndefRecordOffset];
// Parse NDEF record header
byte recordHeader = ndefRecord[0];
byte typeLength = ndefRecord[1];
Serial.print("NDEF Record Header: 0x");
Serial.println(recordHeader, HEX);
Serial.print("Type Length: ");
Serial.println(typeLength);
// Determine payload length (can be 1 or 4 bytes depending on SR flag)
uint32_t payloadLength = 0;
byte payloadLengthBytes = 1;
byte payloadLengthOffset = 2;
// Check if Short Record (SR) flag is set
// Check if Short Record (SR) flag is set (bit 4)
if (recordHeader & 0x10) { // SR flag
payloadLength = ndefRecord[2];
payloadLengthBytes = 1;
payloadLengthOffset = 2;
} else {
// Long record format (4 bytes for payload length)
payloadLength = (ndefRecord[2] << 24) | (ndefRecord[3] << 16) |
(ndefRecord[4] << 8) | ndefRecord[5];
payloadLengthBytes = 4;
payloadLengthOffset = 2;
}
Serial.print("NDEF Record Header: 0x");
Serial.println(recordHeader, HEX);
Serial.print("Type Length: ");
Serial.println(typeLength);
Serial.print("Payload Length: ");
Serial.println(payloadLength);
Serial.print("Payload Length Bytes: ");
Serial.println(payloadLengthBytes);
// Check for ID field (if IL flag is set)
byte idLength = 0;
if (recordHeader & 0x08) { // IL flag
idLength = ndefRecord[payloadLengthOffset + payloadLengthBytes];
Serial.print("ID Length: ");
Serial.println(idLength);
}
// Calculate offset to payload
byte payloadOffset = 2 + payloadLengthBytes + typeLength;
byte payloadOffset = 1 + 1 + payloadLengthBytes + typeLength + idLength;
Serial.print("Calculated payload offset: ");
Serial.println(payloadOffset);
// Verify we have enough data
if (payloadOffset + payloadLength > ndefMessageLength + 2) {
if (payloadOffset + payloadLength > ndefMessageLength) {
Serial.println("Invalid NDEF structure - payload extends beyond message");
Serial.print("Payload offset + length: ");
Serial.print(payloadOffset + payloadLength);
Serial.print(", NDEF message length: ");
Serial.println(ndefMessageLength);
return false;
}
// Print the record type for debugging
Serial.print("Record Type: ");
for (int i = 0; i < typeLength; i++) {
Serial.print((char)ndefRecord[1 + 1 + payloadLengthBytes + i]);
}
Serial.println();
nfcJsonData = "";
// Extract JSON payload
// Extract JSON payload with validation
uint32_t actualJsonLength = 0;
for (uint32_t i = 0; i < payloadLength; i++) {
nfcJsonData += (char)ndefRecord[payloadOffset + i];
byte currentByte = ndefRecord[payloadOffset + i];
// Stop at null terminator or if we find the end of JSON
if (currentByte == 0x00) {
Serial.print("Found null terminator at position: ");
Serial.println(i);
break;
}
// Only add printable characters and common JSON characters
if (currentByte >= 32 && currentByte <= 126) {
nfcJsonData += (char)currentByte;
actualJsonLength++;
} else {
Serial.print("Skipping non-printable byte at position ");
Serial.print(i);
Serial.print(": 0x");
Serial.println(currentByte, HEX);
}
// Check if we've reached the end of a JSON object
if (currentByte == '}') {
// Count opening and closing braces to detect complete JSON
int braceCount = 0;
for (uint32_t j = 0; j <= i; j++) {
if (ndefRecord[payloadOffset + j] == '{') braceCount++;
else if (ndefRecord[payloadOffset + j] == '}') braceCount--;
}
if (braceCount == 0) {
Serial.print("Found complete JSON object at position: ");
Serial.println(i);
actualJsonLength = i + 1;
break;
}
}
}
Serial.print("Actual JSON length extracted: ");
Serial.println(actualJsonLength);
Serial.println("Decoded JSON Data:");
Serial.println(nfcJsonData);
// Trim any trailing whitespace or invalid characters
nfcJsonData.trim();
// JSON-Dokument verarbeiten
JsonDocument doc;
@@ -566,6 +673,18 @@ void scanRfidTask(void * parameter) {
Serial.println("Tag entfernt");
if (!bambuCredentials.autosend_enable) oledShowWeight(weight);
}
// Reset state after successful read when tag is removed
else if (!success && nfcReaderState == NFC_READ_SUCCESS)
{
nfcReaderState = NFC_IDLE;
Serial.println("Tag nach erfolgreichem Lesen entfernt - bereit für nächsten Tag");
}
// Add a longer pause after successful reading to prevent immediate re-reading
if (nfcReaderState == NFC_READ_SUCCESS) {
Serial.println("Tag erfolgreich gelesen - warte 5 Sekunden vor nächstem Scan");
vTaskDelay(5000 / portTICK_PERIOD_MS); // 5 second pause
}
// aktualisieren der Website wenn sich der Status ändert
sendNfcData();