DartでNostrのTLを眺めるやつ

hello_nostr.dart

// flutter pub add nostr

import 'dart:convert';
import 'dart:io';
import 'package:nostr/nostr.dart';

//自分の公開鍵(16進数。https://damus.io/key/ で変換できる)
const yourPubKeyHex =
    "XXXXXXXXXXXXXXXXXXXXXXXXXXXXXX";

class User {
  User(this.pubkey, this.name, this.displayName, this.nip05, this.createdAt);
  String pubkey = "";
  String nip05 = "";
  String displayName = "";
  String name = "";
  int createdAt = 0;

  @override
  String toString() {
    return "$pubkey : $displayName : @$name <$nip05>";
  }
}

void main(List<String> arguments) async {
  List<Event> receivedEvents = List.empty(growable: true);
  Map<String, User> userMap = {};
  bool isEOSE = false;
  bool timelineMode = false;
  print('Hello');

  //リレーサーバーに接続する
  WebSocket webSocket = await WebSocket.connect(
    'wss://nos.lol',
  );

  //メッセージを待ち受ける
  webSocket.listen((payload) {
    if (payload is String) {
      if (!timelineMode) {
        //受信モード
        print('Received event: $payload');
      }
      //ここで種類別のデシリアライズも完了する
      Message m = Message.deserialize(payload);
      switch (m.type) {
        case "EVENT":
          receivedEvents.add(m.message);
          break;
        case "EOSE":
          isEOSE = true;
          break;
        case "OK":
          print('OK!');
          break;
      }
    }
  });

  //Event event = Event.from(kind: kind, tags: tags, content: content, privkey: privkey)

  //リレーから受信したい情報を指定する
  int epochTimeSec_before30day =
      ((DateTime.now().subtract(Duration(days: 30))).millisecondsSinceEpoch /
              1000)
          .floor();

  String followListSubscriptionId = generate64RandomHexChars().substring(0, 32);
  //リレーサーバーから最新のフォローリストを取得する
  Request followListRequest = Request(followListSubscriptionId, [
    Filter(
      //3=連絡先情報
      kinds: [3],
      authors: [yourPubKeyHex],
      //受信する最低時刻
      since: epochTimeSec_before30day,
      //最初に受信するイベント数の上限
      limit: 450,
    )
  ]);

  //要求を送信
  isEOSE = false;
  receivedEvents = List.empty(growable: true);
  webSocket.add(followListRequest.serialize());

  //完了するまで待つ
  while (!isEOSE) {
    await Future.delayed(Duration(milliseconds: 30));
  }

  //要求解除を送信
  webSocket.add(Close(followListSubscriptionId).serialize());

  //最新順にソート
  receivedEvents.sort((a, b) => b.createdAt.compareTo(a.createdAt));

  //何らかの理由でフォローリスト以外のものが出てきたとき
  if (receivedEvents[0].kind != 3) {
    throw "not contact(3)";
  }

  //最新のフォローリストを決定
  String relayList = receivedEvents[0].content;
  List<List<String>> followList = receivedEvents[0].tags;

  //受信先リストを生成
  List<String> followedPubKeys = List.empty(growable: true);
  for (var element in followList) {
    if (element[0] == "p") {
      followedPubKeys.add(element[1]);
    }
  }

  print("==> $followedPubKeys");

  //-------------

  //ユーザー名とアイコンを取得する
  String profileSubscriptionId = generate64RandomHexChars().substring(0, 32);

  Request profileRequest = Request(profileSubscriptionId, [
    Filter(
      //0=メタデータ
      kinds: [0],
      //受信する最低時刻
      since: epochTimeSec_before30day,
      //フォローしてる人リスト
      authors: followedPubKeys,
      //最初に受信するイベント数の上限
      limit: 450,
    )
  ]);

  //要求を送信
  isEOSE = false;
  receivedEvents = List.empty(growable: true);
  webSocket.add(profileRequest.serialize());

  //完了するまで待つ
  while (!isEOSE) {
    await Future.delayed(Duration(milliseconds: 30));
  }

  //要求解除を送信
  webSocket.add(Close(profileSubscriptionId).serialize());

  //解析
  for (var element in receivedEvents) {
    Map<String, dynamic> json = jsonDecode(element.content);

    //存在しないか古い場合は上書きする
    if (!userMap.containsKey(element.pubkey) ||
        userMap[element.pubkey]!.createdAt < element.createdAt) {
      userMap[element.pubkey] = User(
          element.pubkey,
          json["name"] ?? "",
          json["display_name"] == ""
              ? (json["name"] ?? "")
              : (json["display_name"] ?? json["name"] ?? ""),
          json["nip05"] ?? "",
          element.createdAt);
      print(userMap[element.pubkey]);
    }
  }

  print("=====================");
  int epochTimeSec_before30min =
      ((DateTime.now().subtract(Duration(minutes: 30))).millisecondsSinceEpoch /
              1000)
          .floor();
  String messageSubscriptionId = generate64RandomHexChars().substring(0, 32);
  Request request = Request(messageSubscriptionId, [
    Filter(
      //1=テキスト, 2=推奨リレー
      //5=削除イベント, 7=リアクション(+1)
      kinds: [1, 2, 5],
      //受信する最低時刻
      since: epochTimeSec_before30min,
      //フォローしてる人リスト
      authors: followedPubKeys,
      //最初に受信するイベント数の上限
      limit: 450,
    )
  ]);

  //要求を送信
  isEOSE = false;
  receivedEvents = List.empty(growable: true);
  webSocket.add(request.serialize());

  //完了するまで待つ
  while (!isEOSE) {
    await Future.delayed(Duration(milliseconds: 30));
  }

  //最新順にソート
  receivedEvents.sort((a, b) => a.createdAt.compareTo(b.createdAt));

  print("=====================");

  //以降来たら順に出す
  timelineMode = true;
  while (true) {
    await Future.delayed(Duration(seconds: 1));

    if (receivedEvents.isNotEmpty) {
      for (var message in receivedEvents) {
        //TLモード (この実装は極めてイケていない)
        String name = userMap[message.pubkey]?.displayName ?? message.pubkey;
        String nip05 = userMap[message.pubkey]?.nip05 ?? "-";
        print(
            '\n========== ${name} <${nip05}> ========== \n ${message.content}');
      }
      receivedEvents = List.empty(growable: true);
    }
  }

  //要求解除を送信
  webSocket.add(Close(messageSubscriptionId).serialize());
  webSocket.close();
}