初始化

lib/hj_utils/dns_solve/_answer.dart

@@ -0,0 +1,176 @@
+part of '_dnsolve.dart';
+
+/// Represents an answer containing a list of generic records and a list of
+/// Service (SRV) records parsed from JSON data.
+class _Answer {
+  const _Answer(this.records, [this.srvs]);
+
+  /// List of generic records.
+  final List<_Record>? records;
+
+  /// List of Service (SRV) records.
+  final List<SRVRecord>? srvs;
+
+  /// Constructs an [_Answer] instance from JSON data.
+  ///
+  /// The [json] parameter should be a list of dynamic objects representing
+  /// DNS records. Returns an [_Answer] instance containing parsed records
+  /// and Service (SRV) records.
+  factory _Answer.fromJson(List<dynamic>? json) {
+    if (json == null) {
+      return const _Answer(null);
+    }
+
+    final records = json
+        .map((answer) => _Record.fromJson(answer as Map<String, dynamic>))
+        .toList();
+    final srvs = <SRVRecord>[];
+
+    {
+      final RegExp regExp = RegExp(r'(\d+)\s+(\d+)\s+(\d+)\s+([\w\.\-]+)');
+      for (final record in records) {
+        if (record.rType == RecordType.srv) {
+          final match = regExp.firstMatch(record.data);
+
+          if (match != null) {
+            final priority = int.parse(match.group(1)!);
+            final weight = int.parse(match.group(2)!);
+            final port = int.parse(match.group(3)!);
+            final target = match.group(4)!;
+
+            srvs.add(
+              SRVRecord(
+                priority: priority,
+                weight: weight,
+                port: port,
+                target: target,
+                fqdn: record.name,
+              ),
+            );
+          } else {
+            throw const SRVRecordFormatException(
+              'Failed to parse or process the Service (SRV) record',
+            );
+          }
+        }
+      }
+    }
+
+    return _Answer(records, srvs);
+  }
+
+  @override
+  String toString() => '''$records''';
+}
+
+class _Record {
+  const _Record({
+    required this.name,
+    required this.rType,
+    required this.ttl,
+    required this.data,
+  });
+
+  final String name;
+  final RecordType rType;
+  final int ttl;
+  final String data;
+
+  factory _Record.fromJson(Map<String, dynamic> json) => _Record(
+        name: json['name'] as String,
+        rType: DNSolve.intToRecord(json['type'] as int),
+        ttl: json['TTL'] as int,
+        data: json['data'] as String,
+      );
+
+  @override
+  String toString() =>
+      '''(name: $name, type: $rType, ttl: $ttl, data: $data)''';
+
+  String get toBind {
+    final buffer = StringBuffer();
+    buffer.write(name);
+    if (buffer.length < 8) {
+      buffer.write('\t');
+    }
+    if (buffer.length > 10) {
+      buffer.write('\t');
+    }
+    buffer.writeAll(
+      [ttl, '\tIN\t', rType.name.toUpperCase(), '\t', '"', data, '"'],
+    );
+
+    return buffer.toString();
+  }
+}
+
+/// Returns a Service (SRV) record containing information about a server or
+/// service in the domain name system (DNS).
+class SRVRecord {
+  /// Constructs an [SRVRecord] with the specified parameters.
+  const SRVRecord({
+    required this.priority,
+    required this.weight,
+    required this.port,
+    this.target,
+    required this.fqdn,
+  });
+
+  /// The priority of this SRV record.
+  final int priority;
+
+  /// The weight of this SRV record.
+  final int weight;
+
+  /// The port on which the service is available.
+  final int port;
+
+  /// The target domain name of the server.
+  final String? target;
+
+  /// Fully Qualified Domain Name.
+  final String fqdn;
+
+  /// Sorts a list of [SRVRecord] instances based on their priority and weight.
+  static List<SRVRecord> sort(List<SRVRecord> records) {
+    records.sort(_srvRecordSortComparator);
+
+    return records;
+  }
+
+  /// Comparator function for sorting [SRVRecord] instances.
+  static int _srvRecordSortComparator(SRVRecord a, SRVRecord b) {
+    if (a.priority < b.priority) {
+      return -1;
+    } else {
+      if (a.priority > b.priority) {
+        return 1;
+      }
+
+      if (a.weight < b.weight) {
+        return -1;
+      } else if (a.weight > b.weight) {
+        return 1;
+      } else {
+        return 0;
+      }
+    }
+  }
+
+  @override
+  bool operator ==(Object other) {
+    if (identical(this, other)) {
+      return true;
+    }
+
+    return other is SRVRecord &&
+        other.runtimeType == runtimeType &&
+        other.priority == priority &&
+        other.weight == weight &&
+        other.port == port &&
+        other.target == other.target;
+  }
+
+  @override
+  int get hashCode => Object.hash(priority, weight, port, target);
+}