gRPC / gRPC-Web: пример кода

// Reserve retired field numbers so they can never be reused — a real backward-compat trap
message User {
  int32 id = 1;
  string name = 2;
  reserved 3;              // field 3 was 'ssn' — removed; never reuse the NUMBER
  string email = 4;        // new fields are additive & optional
}

// Browser side (gRPC-Web) — generated, typed client. No hand-written fetch/JSON.
import { UserServiceClient } from './gen/user_grpc_web_pb';
const client = new UserServiceClient('https://api.example.com'); // points at the proxy

// unary — works in the browser
const user = await client.getUser({ id: 7 });

// server streaming — works: server pushes many, browser reads
const stream = client.listUsers({ team: 'core' });
stream.on('data', (u) => render(u));
stream.on('end', () => done());

// ❌ client streaming / bidirectional — NOT supported in gRPC-Web.
//    For continuous client→server push from the browser, use a WebSocket.