feat: TXT record in MDNSBrowser

main/platform/MDNSBrowser.h

@@ -1,10 +1,11 @@
 #pragma once
 
-#include <functional>  // for function
-#include <map>         // for map
-#include <memory>      // for unique_ptr
-#include <string>      // for string
-#include <vector>      // for vector
+#include <BellLogger.h>
+#include <functional>     // for function
+#include <memory>         // for unique_ptr
+#include <string>         // for string
+#include <unordered_map>  // for unordered_map
+#include <vector>         // for vector
 
 namespace bell {
 
@@ -17,6 +18,7 @@ class MDNSBrowser {
     std::string name, type, domain, hostname;
 
     std::vector<std::string> ipv4, ipv6;
+    std::unordered_map<std::string, std::string> txtRecords;
     uint16_t port = 0;
 
     bool operator==(const DiscoveredRecord& rhs) const {
@@ -43,6 +45,43 @@ class MDNSBrowser {
   // Starts discovery of passed type and returns implemented browser instance
   static std::unique_ptr<MDNSBrowser> startDiscovery(
       std::string type, RecordsUpdatedCallback callback);
+
+ protected:
+  std::unordered_map<std::string, std::string> parseMDNSTXTRecord(
+      int txtLen, const unsigned char* txtRecord) {
+    std::unordered_map<std::string, std::string> result;
+    int i = 0;
+
+    while (i < txtLen) {
+      // Get the length of the current key-value pair
+      int length = txtRecord[i];
+      i++;
+
+      if (i + length > txtLen) {
+        // This should not happen if the input is well-formed
+        BELL_LOG(error, "MDNSBrowser", "Cannot parse ill-formed txt record");
+        break;
+      }
+
+      // Extract the key-value pair
+      std::string pair(reinterpret_cast<const char*>(txtRecord + i), length);
+      i += length;
+
+      // Find the position of the '=' character
+      size_t pos = pair.find('=');
+      if (pos != std::string::npos) {
+        // Split into key and value
+        std::string key = pair.substr(0, pos);
+        std::string value = pair.substr(pos + 1);
+        result[key] = value;
+      } else {
+        // If there's no '=', then it's just a key with an empty value
+        result[pair] = "";
+      }
+    }
+
+    return result;
+  }
 };
 
 }  // namespace bell

main/platform/apple/MDNSBrowser.cpp

@@ -8,6 +8,7 @@
 #include <unistd.h>
 #include <atomic>  // for function
 #include <stdexcept>
+#include <string>
 #include <utility>  // for pair
 #include "BellLogger.h"
 #include "dns_sd.h"  // for DNSServiceRef, DNSServiceRefDeallocate, DNS...
@@ -28,6 +29,7 @@ class implMDNSBrowser : public MDNSBrowser {
   struct AddrResolvReference {
     implMDNSBrowser* parentPtr;
     std::string name, type, domain;
+    std::unordered_map<std::string, std::string> txtRecords;
     int port = 0;
   };
 
@@ -63,6 +65,7 @@ class implMDNSBrowser : public MDNSBrowser {
       for (auto& record : discoveredRecords) {
         if (record.name == ctx->name && record.domain == ctx->domain &&
             record.type == ctx->type) {
+          record.txtRecords = ctx->txtRecords;
           record.hostname = hostname;
           record.ipv4.push_back(addrStr);
           record.port = ctx->port;
@@ -98,6 +101,7 @@ class implMDNSBrowser : public MDNSBrowser {
                                  const unsigned char* txtRecord) {
     auto refCopy = service;
     if (ctx->parentPtr != NULL) {
+      ctx->txtRecords = parseMDNSTXTRecord(txtLen, txtRecord);
       auto error = DNSServiceGetAddrInfo(
           &refCopy, kDNSServiceFlagsShareConnection, 0,
           kDNSServiceProtocol_IPv4, hostTarget, getAddrInfoReply, ctx);

main/platform/esp/MDNSBrowser.cpp

@@ -62,6 +62,11 @@ class implMDNSBrowser : public MDNSBrowser {
         a = a->next;
       }
 
+      // copy txt records int std::unordered_map
+      for (int x = 0; x < r->txt_count; x++) {
+        record.txtRecords.insert({std::string(r->txt[x].key), std::string(&r->txt[x].value[0], &r->txt[x].value[r->txt_value_len[x]])});
+      }
+
       discoveredRecords.push_back(record);
       r = r->next;
     }