Extend nfc ndef records with Text (#2191)

Co-authored-by: Oxan van Leeuwen <oxan@oxanvanleeuwen.nl>

esphome/components/nfc/ndef_message.cpp

@@ -10,16 +10,13 @@ NdefMessage::NdefMessage(std::vector<uint8_t> &data) {
   uint8_t index = 0;
   while (index <= data.size()) {
     uint8_t tnf_byte = data[index++];
-    bool me = tnf_byte & 0x40;
-    bool sr = tnf_byte & 0x10;
-    bool il = tnf_byte & 0x08;
-    uint8_t tnf = tnf_byte & 0x07;
+    bool me = tnf_byte & 0x40;      // Message End bit (is set if this is the last record of the message)
+    bool sr = tnf_byte & 0x10;      // Short record bit (is set if payload size is less or equal to 255 bytes)
+    bool il = tnf_byte & 0x08;      // ID length bit (is set if ID Length field exists)
+    uint8_t tnf = tnf_byte & 0x07;  // Type Name Format
 
     ESP_LOGVV(TAG, "me=%s, sr=%s, il=%s, tnf=%d", YESNO(me), YESNO(sr), YESNO(il), tnf);
 
-    auto record = make_unique<NdefRecord>();
-    record->set_tnf(tnf);
-
     uint8_t type_length = data[index++];
     uint32_t payload_length = 0;
     if (sr) {
@@ -38,28 +35,34 @@ NdefMessage::NdefMessage(std::vector<uint8_t> &data) {
     ESP_LOGVV(TAG, "Lengths: type=%d, payload=%d, id=%d", type_length, payload_length, id_length);
 
     std::string type_str(data.begin() + index, data.begin() + index + type_length);
-    record->set_type(type_str);
+
     index += type_length;
 
+    std::string id_str = "";
     if (il) {
-      std::string id_str(data.begin() + index, data.begin() + index + id_length);
-      record->set_id(id_str);
+      id_str = std::string(data.begin() + index, data.begin() + index + id_length);
       index += id_length;
     }
 
-    uint8_t payload_identifier = 0x00;
-    if (type_str == "U") {
-      payload_identifier = data[index++];
-      payload_length -= 1;
+    std::vector<uint8_t> payload_data(data.begin() + index, data.begin() + index + payload_length);
+
+    std::unique_ptr<NdefRecord> record;
+
+    // Based on tnf and type, create a more specific NdefRecord object
+    // constructed from the payload data
+    if (tnf == TNF_WELL_KNOWN && type_str == "U") {
+      record = make_unique<NdefRecordUri>(payload_data);
+    } else if (tnf == TNF_WELL_KNOWN && type_str == "T") {
+      record = make_unique<NdefRecordText>(payload_data);
+    } else {
+      // Could not recognize the record, so store as generic one.
+      record = make_unique<NdefRecord>(payload_data);
+      record->set_tnf(tnf);
+      record->set_type(type_str);
     }
 
-    std::string payload_str(data.begin() + index, data.begin() + index + payload_length);
+    record->set_id(id_str);
 
-    if (payload_identifier > 0x00 && payload_identifier <= PAYLOAD_IDENTIFIERS_COUNT) {
-      payload_str.insert(0, PAYLOAD_IDENTIFIERS[payload_identifier]);
-    }
-
-    record->set_payload(payload_str);
     index += payload_length;
 
     ESP_LOGV(TAG, "Adding record type %s = %s", record->get_type().c_str(), record->get_payload().c_str());
@@ -82,13 +85,10 @@ bool NdefMessage::add_record(std::unique_ptr<NdefRecord> record) {
 bool NdefMessage::add_text_record(const std::string &text) { return this->add_text_record(text, "en"); };
 
 bool NdefMessage::add_text_record(const std::string &text, const std::string &encoding) {
-  std::string payload = to_string(text.length()) + encoding + text;
-  return this->add_record(make_unique<NdefRecord>(TNF_WELL_KNOWN, "T", payload));
+  return this->add_record(make_unique<NdefRecordText>(encoding, text));
 }
 
-bool NdefMessage::add_uri_record(const std::string &uri) {
-  return this->add_record(make_unique<NdefRecord>(TNF_WELL_KNOWN, "U", uri));
-}
+bool NdefMessage::add_uri_record(const std::string &uri) { return this->add_record(make_unique<NdefRecordUri>(uri)); }
 
 std::vector<uint8_t> NdefMessage::encode() {
   std::vector<uint8_t> data;

esphome/components/nfc/ndef_message.h

@@ -5,6 +5,8 @@
 #include "esphome/core/helpers.h"
 #include "esphome/core/log.h"
 #include "ndef_record.h"
+#include "ndef_record_text.h"
+#include "ndef_record_uri.h"
 
 namespace esphome {
 namespace nfc {
@@ -18,7 +20,7 @@ class NdefMessage {
   NdefMessage(const NdefMessage &msg) {
     records_.reserve(msg.records_.size());
     for (const auto &r : msg.records_) {
-      records_.emplace_back(make_unique<NdefRecord>(*r));
+      records_.emplace_back(r->clone());
     }
   }
 

esphome/components/nfc/ndef_record.cpp

@@ -5,40 +5,22 @@ namespace nfc {
 
 static const char *const TAG = "nfc.ndef_record";
 
-uint32_t NdefRecord::get_encoded_size() {
-  uint32_t size = 2;
-  if (this->payload_.length() > 255) {
-    size += 4;
-  } else {
-    size += 1;
-  }
-  if (this->id_.length()) {
-    size += 1;
-  }
-  size += (this->type_.length() + this->payload_.length() + this->id_.length());
-  return size;
+NdefRecord::NdefRecord(std::vector<uint8_t> payload_data) {
+  this->payload_ = std::string(payload_data.begin(), payload_data.end());
 }
 
 std::vector<uint8_t> NdefRecord::encode(bool first, bool last) {
   std::vector<uint8_t> data;
 
-  data.push_back(this->get_tnf_byte(first, last));
+  // Get encoded payload, this is overriden by more specific record classes
+  std::vector<uint8_t> payload_data = get_encoded_payload();
+
+  size_t payload_length = payload_data.size();
+
+  data.push_back(this->create_flag_byte(first, last, payload_length));
 
   data.push_back(this->type_.length());
 
-  uint8_t payload_prefix = 0x00;
-  uint8_t payload_prefix_length = 0x00;
-  for (uint8_t i = 1; i < PAYLOAD_IDENTIFIERS_COUNT; i++) {
-    std::string prefix = PAYLOAD_IDENTIFIERS[i];
-    if (this->payload_.substr(0, prefix.length()).find(prefix) != std::string::npos) {
-      payload_prefix = i;
-      payload_prefix_length = prefix.length();
-      break;
-    }
-  }
-
-  uint32_t payload_length = this->payload_.length() - payload_prefix_length + 1;
-
   if (payload_length <= 255) {
     data.push_back(payload_length);
   } else {
@@ -58,25 +40,23 @@ std::vector<uint8_t> NdefRecord::encode(bool first, bool last) {
     data.insert(data.end(), this->id_.begin(), this->id_.end());
   }
 
-  data.push_back(payload_prefix);
-
-  data.insert(data.end(), this->payload_.begin() + payload_prefix_length, this->payload_.end());
+  data.insert(data.end(), payload_data.begin(), payload_data.end());
   return data;
 }
 
-uint8_t NdefRecord::get_tnf_byte(bool first, bool last) {
-  uint8_t value = this->tnf_;
+uint8_t NdefRecord::create_flag_byte(bool first, bool last, size_t payload_size) {
+  uint8_t value = this->tnf_ & 0b00000111;
   if (first) {
-    value = value | 0x80;
+    value = value | 0x80;  // Set MB bit
   }
   if (last) {
-    value = value | 0x40;
+    value = value | 0x40;  // Set ME bit
   }
-  if (this->payload_.length() <= 255) {
-    value = value | 0x10;
+  if (payload_size <= 255) {
+    value = value | 0x10;  // Set SR bit
   }
   if (this->id_.length()) {
-    value = value | 0x08;
+    value = value | 0x08;  // Set IL bit
   }
   return value;
 };

esphome/components/nfc/ndef_record.h

@@ -15,86 +15,40 @@ static const uint8_t TNF_UNKNOWN = 0x05;
 static const uint8_t TNF_UNCHANGED = 0x06;
 static const uint8_t TNF_RESERVED = 0x07;
 
-static const uint8_t PAYLOAD_IDENTIFIERS_COUNT = 0x23;
-static const char *const PAYLOAD_IDENTIFIERS[] = {"",
-                                                  "http://www.",
-                                                  "https://www.",
-                                                  "http://",
-                                                  "https://",
-                                                  "tel:",
-                                                  "mailto:",
-                                                  "ftp://anonymous:anonymous@",
-                                                  "ftp://ftp.",
-                                                  "ftps://",
-                                                  "sftp://",
-                                                  "smb://",
-                                                  "nfs://",
-                                                  "ftp://",
-                                                  "dav://",
-                                                  "news:",
-                                                  "telnet://",
-                                                  "imap:",
-                                                  "rtsp://",
-                                                  "urn:",
-                                                  "pop:",
-                                                  "sip:",
-                                                  "sips:",
-                                                  "tftp:",
-                                                  "btspp://",
-                                                  "btl2cap://",
-                                                  "btgoep://",
-                                                  "tcpobex://",
-                                                  "irdaobex://",
-                                                  "file://",
-                                                  "urn:epc:id:",
-                                                  "urn:epc:tag:",
-                                                  "urn:epc:pat:",
-                                                  "urn:epc:raw:",
-                                                  "urn:epc:",
-                                                  "urn:nfc:"};
-
 class NdefRecord {
  public:
   NdefRecord(){};
-  NdefRecord(uint8_t tnf, const std::string &type, const std::string &payload) {
-    this->tnf_ = tnf;
-    this->type_ = type;
-    this->set_payload(payload);
-  };
-  NdefRecord(uint8_t tnf, const std::string &type, const std::string &payload, const std::string &id) {
-    this->tnf_ = tnf;
-    this->type_ = type;
-    this->set_payload(payload);
-    this->id_ = id;
-  };
-  NdefRecord(const NdefRecord &rhs) {
-    this->tnf_ = rhs.tnf_;
-    this->type_ = rhs.type_;
-    this->payload_ = rhs.payload_;
-    this->payload_identifier_ = rhs.payload_identifier_;
-    this->id_ = rhs.id_;
-  };
+  NdefRecord(std::vector<uint8_t> payload_data);
   void set_tnf(uint8_t tnf) { this->tnf_ = tnf; };
   void set_type(const std::string &type) { this->type_ = type; };
-  void set_payload_identifier(uint8_t payload_identifier) { this->payload_identifier_ = payload_identifier; };
   void set_payload(const std::string &payload) { this->payload_ = payload; };
   void set_id(const std::string &id) { this->id_ = id; };
+  NdefRecord(const NdefRecord &) = default;
+  virtual ~NdefRecord() {}
+  virtual std::unique_ptr<NdefRecord> clone() const {  // To allow copying polymorphic classes
+    return make_unique<NdefRecord>(*this);
+  };
 
   uint32_t get_encoded_size();
 
   std::vector<uint8_t> encode(bool first, bool last);
-  uint8_t get_tnf_byte(bool first, bool last);
+
+  uint8_t create_flag_byte(bool first, bool last, size_t payload_size);
 
   const std::string &get_type() const { return this->type_; };
   const std::string &get_id() const { return this->id_; };
-  const std::string &get_payload() const { return this->payload_; };
+  virtual const std::string &get_payload() const { return this->payload_; };
+
+  virtual std::vector<uint8_t> get_encoded_payload() {
+    std::vector<uint8_t> empty_payload;
+    return empty_payload;
+  };
 
  protected:
   uint8_t tnf_;
   std::string type_;
-  uint8_t payload_identifier_;
-  std::string payload_;
   std::string id_;
+  std::string payload_;
 };
 
 }  // namespace nfc

esphome/components/nfc/ndef_record_text.cpp

@@ -0,0 +1,40 @@
+#include "ndef_record_text.h"
+#include "ndef_record.h"
+
+namespace esphome {
+namespace nfc {
+
+static const char *const TAG = "nfc.ndef_record_text";
+
+NdefRecordText::NdefRecordText(const std::vector<uint8_t> &payload) {
+  if (payload.empty()) {
+    ESP_LOGE(TAG, "Record payload too short");
+    return;
+  }
+
+  uint8_t language_code_length = payload[0] & 0b00111111;  // Todo, make use of encoding bit?
+
+  this->language_code_ = std::string(payload.begin() + 1, payload.begin() + 1 + language_code_length);
+
+  this->text_ = std::string(payload.begin() + 1 + language_code_length, payload.end());
+
+  this->tnf_ = TNF_WELL_KNOWN;
+
+  this->type_ = "T";
+}
+
+std::vector<uint8_t> NdefRecordText::get_encoded_payload() {
+  std::vector<uint8_t> data;
+
+  uint8_t flag_byte = this->language_code_.length() & 0b00111111;  // UTF8 assumed
+
+  data.push_back(flag_byte);
+
+  data.insert(data.end(), this->language_code_.begin(), this->language_code_.end());
+
+  data.insert(data.end(), this->text_.begin(), this->text_.end());
+  return data;
+}
+
+}  // namespace nfc
+}  // namespace esphome

esphome/components/nfc/ndef_record_text.h

@@ -0,0 +1,41 @@
+#pragma once
+
+#include "esphome/core/log.h"
+#include "esphome/core/helpers.h"
+#include "ndef_record.h"
+
+namespace esphome {
+namespace nfc {
+
+class NdefRecordText : public NdefRecord {
+ public:
+  NdefRecordText(){};
+  NdefRecordText(const std::vector<uint8_t> &payload);
+  NdefRecordText(const std::string &language_code, const std::string &text) {
+    this->tnf_ = TNF_WELL_KNOWN;
+    this->type_ = "T";
+    this->language_code_ = language_code;
+    this->text_ = text;
+  };
+  NdefRecordText(const std::string &language_code, const std::string &text, const std::string &id) {
+    this->tnf_ = TNF_WELL_KNOWN;
+    this->type_ = "T";
+    this->language_code_ = language_code;
+    this->text_ = text;
+    this->id_ = id;
+  };
+  NdefRecordText(const NdefRecordText &) = default;
+
+  std::unique_ptr<NdefRecord> clone() const override { return make_unique<NdefRecordText>(*this); };
+
+  std::vector<uint8_t> get_encoded_payload() override;
+
+  const std::string &get_payload() const override { return this->text_; };
+
+ protected:
+  std::string text_;
+  std::string language_code_;
+};
+
+}  // namespace nfc
+}  // namespace esphome

esphome/components/nfc/ndef_record_uri.cpp

@@ -0,0 +1,48 @@
+#include "ndef_record_uri.h"
+
+namespace esphome {
+namespace nfc {
+
+static const char *const TAG = "nfc.ndef_record_uri";
+
+NdefRecordUri::NdefRecordUri(const std::vector<uint8_t> &payload) {
+  if (payload.empty()) {
+    ESP_LOGE(TAG, "Record payload too short");
+    return;
+  }
+
+  uint8_t payload_identifier = payload[0];  // First byte of payload is prefix code
+
+  std::string uri(payload.begin() + 1, payload.end());
+
+  if (payload_identifier > 0x00 && payload_identifier <= PAYLOAD_IDENTIFIERS_COUNT) {
+    uri.insert(0, PAYLOAD_IDENTIFIERS[payload_identifier]);
+  }
+
+  this->tnf_ = TNF_WELL_KNOWN;
+  this->type_ = "U";
+  this->set_URI(uri);
+}
+
+std::vector<uint8_t> NdefRecordUri::get_encoded_payload() {
+  std::vector<uint8_t> data;
+
+  uint8_t payload_prefix = 0x00;
+  uint8_t payload_prefix_length = 0x00;
+  for (uint8_t i = 1; i < PAYLOAD_IDENTIFIERS_COUNT; i++) {
+    std::string prefix = PAYLOAD_IDENTIFIERS[i];
+    if (this->URI_.substr(0, prefix.length()).find(prefix) != std::string::npos) {
+      payload_prefix = i;
+      payload_prefix_length = prefix.length();
+      break;
+    }
+  }
+
+  data.push_back(payload_prefix);
+
+  data.insert(data.end(), this->URI_.begin() + payload_prefix_length, this->URI_.end());
+  return data;
+}
+
+}  // namespace nfc
+}  // namespace esphome

esphome/components/nfc/ndef_record_uri.h

@@ -0,0 +1,76 @@
+#pragma once
+
+#include "esphome/core/log.h"
+#include "esphome/core/helpers.h"
+#include "ndef_record.h"
+
+namespace esphome {
+namespace nfc {
+
+static const uint8_t PAYLOAD_IDENTIFIERS_COUNT = 0x23;
+static const char *const PAYLOAD_IDENTIFIERS[] = {"",
+                                                  "http://www.",
+                                                  "https://www.",
+                                                  "http://",
+                                                  "https://",
+                                                  "tel:",
+                                                  "mailto:",
+                                                  "ftp://anonymous:anonymous@",
+                                                  "ftp://ftp.",
+                                                  "ftps://",
+                                                  "sftp://",
+                                                  "smb://",
+                                                  "nfs://",
+                                                  "ftp://",
+                                                  "dav://",
+                                                  "news:",
+                                                  "telnet://",
+                                                  "imap:",
+                                                  "rtsp://",
+                                                  "urn:",
+                                                  "pop:",
+                                                  "sip:",
+                                                  "sips:",
+                                                  "tftp:",
+                                                  "btspp://",
+                                                  "btl2cap://",
+                                                  "btgoep://",
+                                                  "tcpobex://",
+                                                  "irdaobex://",
+                                                  "file://",
+                                                  "urn:epc:id:",
+                                                  "urn:epc:tag:",
+                                                  "urn:epc:pat:",
+                                                  "urn:epc:raw:",
+                                                  "urn:epc:",
+                                                  "urn:nfc:"};
+
+class NdefRecordUri : public NdefRecord {
+ public:
+  NdefRecordUri(){};
+  NdefRecordUri(const std::vector<uint8_t> &payload);
+  NdefRecordUri(const std::string &URI) {
+    this->tnf_ = TNF_WELL_KNOWN;
+    this->type_ = "U";
+    this->URI_ = URI;
+  };
+  NdefRecordUri(const std::string &URI, const std::string &id) {
+    this->tnf_ = TNF_WELL_KNOWN;
+    this->type_ = "U";
+    this->URI_ = URI;
+    this->id_ = id;
+  };
+  NdefRecordUri(const NdefRecordUri &) = default;
+  std::unique_ptr<NdefRecord> clone() const override { return make_unique<NdefRecordUri>(*this); };
+
+  void set_URI(const std::string &URI) { this->URI_ = URI; };
+
+  std::vector<uint8_t> get_encoded_payload() override;
+  const std::string &get_payload() const override { return this->URI_; };
+
+ protected:
+  std::string URI_;
+};
+
+}  // namespace nfc
+}  // namespace esphome