refactor: add json serializable

lib/src/event.dart

@@ -2,8 +2,11 @@ import 'dart:convert';
 import 'package:convert/convert.dart';
 import 'package:crypto/crypto.dart';
 import 'package:bip340/bip340.dart' as bip340;
+import 'package:json_annotation/json_annotation.dart';
 import 'package:nostr/src/utils.dart';
 
+part 'event.g.dart';
+
 /// The only object type that exists is the event, which has the following format on the wire:
 ///
 /// - "id": "32-bytes hex-encoded sha256 of the the serialized event data"
@@ -16,6 +19,7 @@ import 'package:nostr/src/utils.dart';
 ///  ],
 /// - "content": "arbitrary string",
 /// - "sig": "64-bytes signature of the sha256 hash of the serialized event data, which is the same as the 'id' field"
+@JsonSerializable()
 class Event {
   /// 32-bytes hex-encoded sha256 of the the serialized event data (hex)
   late String id;
@@ -24,37 +28,42 @@ class Event {
   late String pubkey;
 
   /// unix timestamp in seconds
-  late int createdAt;
+  @JsonKey(
+    name: 'created_at',
+  )
+  int createdAt;
 
   /// -  0: set_metadata: the content is set to a stringified JSON object {name: <username>, about: <string>, picture: <url, string>} describing the user who created the event. A relay may delete past set_metadata events once it gets a new one for the same pubkey.
   /// -  1: text_note: the content is set to the text content of a note (anything the user wants to say). Non-plaintext notes should instead use kind 1000-10000 as described in NIP-16.
   /// -  2: recommend_server: the content is set to the URL (e.g., wss://somerelay.com) of a relay the event creator wants to recommend to its followers.
-  late int kind;
+  final int kind;
 
   /// The tags array can store a tag identifier as the first element of each subarray, plus arbitrary information afterward (always as strings).
   ///
   /// This NIP defines "p" — meaning "pubkey", which points to a pubkey of someone that is referred to in the event —, and "e" — meaning "event", which points to the id of an event this event is quoting, replying to or referring to somehow.
-  late List<List<String>> tags;
+  final List<List<String>> tags;
 
   /// arbitrary string
-  String content = "";
+  @JsonKey(defaultValue: '')
+  String content;
 
   /// 64-bytes signature of the sha256 hash of the serialized event data, which is the same as the "id" field
   late String sig;
 
   /// subscription_id is a random string that should be used to represent a subscription.
+  @JsonKey(includeIfNull: false, toJson: null)
   String? subscriptionId;
 
-  /// Default constructor
   Event(
     this.id,
     this.pubkey,
     this.createdAt,
     this.kind,
     this.tags,
     this.content,
-    this.sig,
-  ) {
+    this.sig, {
+    this.subscriptionId,
+  }) {
     assert(createdAt.toString().length == 10);
     assert(createdAt <= currentUnixTimestampSeconds());
     pubkey = pubkey.toLowerCase();
@@ -63,47 +72,36 @@ class Event {
     assert(bip340.verify(pubkey, id, sig));
   }
 
-  /// Instanciate Event object from the minimum available data
-  Event.from(
-      {this.createdAt = 0,
-      required this.kind,
-      required this.tags,
-      required this.content,
-      required String privkey,
-      this.subscriptionId}) {
-    if (createdAt == 0) {
-      createdAt = currentUnixTimestampSeconds();
-    }
-    assert(createdAt.toString().length == 10);
-    assert(createdAt <= currentUnixTimestampSeconds());
-    pubkey = bip340.getPublicKey(privkey).toLowerCase();
-    id = getEventId();
-    sig = getSignature(privkey);
-  }
+  factory Event.fromJson(Map<String, dynamic> json) => _$EventFromJson(json);
 
-  /// Deserialize an event from a JSON
-  Event.fromJson(Map<String, dynamic> json, {this.subscriptionId}) {
-    id = json['id'];
-    pubkey = json['pubkey'];
-    createdAt = json['created_at'];
-    kind = json['kind'];
-    tags = (json['tags'] as List<dynamic>)
-        .map((e) => (e as List<dynamic>).map((e) => e as String).toList())
-        .toList();
-    content = json['content'];
-    sig = json['sig'];
+  Map<String, dynamic> toJson() => _$EventToJson(this);
+
+  /// To obtain the event.id, we sha256 the serialized event.
+  /// The serialization is done over the UTF-8 JSON-serialized string (with no white space or line breaks) of the following structure:
+  ///
+  ///[
+  ///  0,
+  ///  <pubkey, as a (lowercase) hex string>,
+  ///  <created_at, as a number>,
+  ///  <kind, as a number>,
+  ///  <tags, as an array of arrays of non-null strings>,
+  ///  <content, as a string>
+  ///]
+  String getEventId() {
+    List data = [0, pubkey.toLowerCase(), createdAt, kind, tags, content];
+    String serializedEvent = json.encode(data);
+    List<int> hash = sha256.convert(utf8.encode(serializedEvent)).bytes;
+    return hex.encode(hash);
   }
 
-  /// Serialize an event in JSON
-  Map<String, dynamic> toJson() => {
-        'id': id,
-        'pubkey': pubkey,
-        'created_at': createdAt,
-        'kind': kind,
-        'tags': tags,
-        'content': content,
-        'sig': sig
-      };
+  /// Each user has a keypair. Signatures, public key, and encodings are done according to the Schnorr signatures standard for the curve secp256k1
+  /// 64-bytes signature of the sha256 hash of the serialized event data, which is the same as the "id" field
+  String getSignature(String privateKey) {
+    /// aux must be 32-bytes random bytes, generated at signature time.
+    /// https://github.com/nbd-wtf/dart-bip340/blob/master/lib/src/bip340.dart#L10
+    String aux = generate64RandomHexChars();
+    return bip340.sign(privateKey, id, aux);
+  }
 
   /// Serialize to nostr event message
   /// - ["EVENT", event JSON as defined above]
@@ -119,51 +117,43 @@ class Event {
   /// Deserialize a nostr event message
   /// - ["EVENT", event JSON as defined above]
   /// - ["EVENT", subscription_id, event JSON as defined above]
-  Event.deserialize(input) {
+  factory Event.deserialize(input) {
     Map<String, dynamic> json = {};
     if (input.length == 2) {
       json = input[1] as Map<String, dynamic>;
+
+      final event = _$EventFromJson(json);
+
+      return event;
     } else if (input.length == 3) {
       json = input[2] as Map<String, dynamic>;
-      subscriptionId = input[1];
+      json['subscriptionId'] = input[1];
+
+      final event = _$EventFromJson(json);
+
+      return event;
     } else {
       throw Exception('invalid input');
     }
-    id = json['id'];
-    pubkey = json['pubkey'];
-    createdAt = json['created_at'];
-    kind = json['kind'];
-    tags = (json['tags'] as List<dynamic>)
-        .map((e) => (e as List<dynamic>).map((e) => e as String).toList())
-        .toList();
-    content = json['content'];
-    sig = json['sig'];
-  }
-
-  /// To obtain the event.id, we sha256 the serialized event.
-  /// The serialization is done over the UTF-8 JSON-serialized string (with no white space or line breaks) of the following structure:
-  ///
-  ///[
-  ///  0,
-  ///  <pubkey, as a (lowercase) hex string>,
-  ///  <created_at, as a number>,
-  ///  <kind, as a number>,
-  ///  <tags, as an array of arrays of non-null strings>,
-  ///  <content, as a string>
-  ///]
-  String getEventId() {
-    List data = [0, pubkey.toLowerCase(), createdAt, kind, tags, content];
-    String serializedEvent = json.encode(data);
-    List<int> hash = sha256.convert(utf8.encode(serializedEvent)).bytes;
-    return hex.encode(hash);
   }
 
-  /// Each user has a keypair. Signatures, public key, and encodings are done according to the Schnorr signatures standard for the curve secp256k1
-  /// 64-bytes signature of the sha256 hash of the serialized event data, which is the same as the "id" field
-  String getSignature(String privateKey) {
-    /// aux must be 32-bytes random bytes, generated at signature time.
-    /// https://github.com/nbd-wtf/dart-bip340/blob/master/lib/src/bip340.dart#L10
-    String aux = generate64RandomHexChars();
-    return bip340.sign(privateKey, id, aux);
+  /// Instanciate Event object from the minimum available data
+  Event.from(
+      {this.createdAt = 0,
+      required this.kind,
+      required this.tags,
+      required this.content,
+      required String privkey,
+      this.subscriptionId}) {
+    if (createdAt == 0) {
+      createdAt = currentUnixTimestampSeconds();
+    } else {
+      createdAt = createdAt;
+    }
+    assert(createdAt.toString().length == 10);
+    assert(createdAt <= currentUnixTimestampSeconds());
+    pubkey = bip340.getPublicKey(privkey).toLowerCase();
+    id = getEventId();
+    sig = getSignature(privkey);
   }
 }

lib/src/filter.dart

@@ -1,4 +1,9 @@
+import 'package:json_annotation/json_annotation.dart';
+
+part 'filter.g.dart';
+
 /// filter is a JSON object that determines what events will be sent in that subscription
+@JsonSerializable(includeIfNull: false)
 class Filter {
   /// a list of event ids or prefixes
   List<String>? ids;
@@ -10,9 +15,11 @@ class Filter {
   List<int>? kinds;
 
   /// a list of event ids that are referenced in an "e" tag
+  @JsonKey(name: '#e')
   List<String>? e;
 
   /// a list of pubkeys that are referenced in a "p" tag
+  @JsonKey(name: '#p')
   List<String>? p;
 
   /// a timestamp, events must be newer than this to pass
@@ -25,56 +32,18 @@ class Filter {
   int? limit;
 
   /// Default constructor
-  Filter(
-      {this.ids,
-      this.authors,
-      this.kinds,
-      this.e,
-      this.p,
-      this.since,
-      this.until,
-      this.limit});
-
-  /// Deserialize a filter from a JSON
-  Filter.fromJson(Map<String, dynamic> json) {
-    ids = json['ids'] == null ? null : List<String>.from(json['ids']);
-    authors =
-        json['authors'] == null ? null : List<String>.from(json['authors']);
-    kinds = json['kinds'] == null ? null : List<int>.from(json['kinds']);
-    e = json['#e'] == null ? null : List<String>.from(json['#e']);
-    p = json['#p'] == null ? null : List<String>.from(json['#p']);
-    since = json['since'];
-    until = json['until'];
-    limit = json['limit'];
-  }
-
-  /// Serialize a filter in JSON
-  Map<String, dynamic> toJson() {
-    final Map<String, dynamic> data = <String, dynamic>{};
-    if (ids != null) {
-      data['ids'] = ids;
-    }
-    if (authors != null) {
-      data['authors'] = authors;
-    }
-    if (kinds != null) {
-      data['kinds'] = kinds;
-    }
-    if (e != null) {
-      data['#e'] = e;
-    }
-    if (p != null) {
-      data['#p'] = p;
-    }
-    if (since != null) {
-      data['since'] = since;
-    }
-    if (until != null) {
-      data['until'] = until;
-    }
-    if (limit != null) {
-      data['limit'] = limit;
-    }
-    return data;
-  }
+  Filter({
+    this.ids,
+    this.authors,
+    this.kinds,
+    this.e,
+    this.p,
+    this.since,
+    this.until,
+    this.limit,
+  });
+
+  factory Filter.fromJson(Map<String, dynamic> json) => _$FilterFromJson(json);
+
+  Map<String, dynamic> toJson() => _$FilterToJson(this);
 }