Dart - Use the HTTP API for Pusher

pusher.dart

import 'package:http/http.dart' as http;
import 'package:crypto/crypto.dart';
import 'dart:convert';

class Pusher {
  // Replace -us3 with -YOUR_REGION
  static String baseUrl = "https://api-us3.pusher.com/apps";

  final String appId;
  final String appKey;
  final String secret;

  const Pusher({
    required this.appId,
    required this.appKey,
    required this.secret,
  });

  String getFullUrl(String channel, String event, String bodyStr) {
    String timestamp =
        (DateTime.now().millisecondsSinceEpoch / 1000).round().toString();
    String authVersion = "1.0";
    var bodyMD5 = md5.convert(utf8.encode(bodyStr));
    String signStr = """POST
/apps/${this.appId}/events
auth_key=${this.appKey}&auth_timestamp=${timestamp}&auth_version=$authVersion&body_md5=${bodyMD5}""";
    var authSignature =
        Hmac(sha256, utf8.encode(this.secret)).convert(utf8.encode(signStr));

    return '$baseUrl/${this.appId}/events?body_md5=$bodyMD5&auth_version=1.0&auth_key=${this.appKey}&auth_timestamp=$timestamp&auth_signature=$authSignature';
  }

  Future<int> triggerEvent(String channel, String event, Map data) async {
    String bodyStr = json.encode({
      'name': event,
      'channel': channel,
      'data': json.encode(data),
    });
    var uri = Uri.parse(getFullUrl(channel, event, bodyStr));
    var response = await http.post(
      uri,
      headers: <String, String>{
        'Content-Type': 'application/json',
      },
      body: bodyStr,
    );

    return response.statusCode;
  }
}

void main() async {
  print("Program started!");

  Pusher pusher = Pusher(
    appId: "YOUR_APP_ID",
    appKey: "YOUR_APP_KEY",
    secret: "YOUR_SECRET",
  );

  int resCode = await pusher.triggerEvent("CHANNEL", "EVENT_NAME", {
    'message': 'Hello World',
  });

  print(resCode); // 200 (hopefully)
}