Suscripciones

Un servidor aparte

On a deployment behind a reverse proxy, both /ws and /ws/ are served as two separate locations with no redirect between them: a WebSocket client mostly does not follow a 301 on its handshake, so whichever spelling was redirected would simply fail to connect.

El handshake

eth_subscribe y pickle_subscribe se aceptan indistintamente y se comportan igual:

// ->
{"jsonrpc":"2.0","id":1,"method":"pickle_subscribe","params":["miniBlocks"]}

// <-
{"jsonrpc":"2.0","id":1,"result":"0x1"}

// <- then, per event
{"jsonrpc":"2.0","method":"eth_subscription","params":{"subscription":"0x1","result":{…}}}

• Subscription ids come from a per-connection counter starting at 1, so two connections both see 0x1. Do not treat an id as globally unique.
• Notifications always arrive under the method name eth_subscription, even for a subscription opened as pickle_subscribe. Unwrap the payload at params.result.
• eth_unsubscribe and pickle_unsubscribe both return a boolean: true if the id was found on this connection, false otherwise.

Los cuatro tipos

Un ejemplo completo

El flujo de minibloques, con la vía de reserva que usa el feed de primera parte. La vía de reserva importa: un socket caído es normal, y el sondeo es la forma de recuperar el retraso sin huecos.

// WS_URL: wss://rpc.picklechain.xyz/ws/ on the public testnet, or a node of your own.
// The /ws path is required - an upgrade at the bare origin answers 405.
const socket = new WebSocket(WS_URL);

socket.addEventListener("open", () => {
  socket.send(JSON.stringify({
    jsonrpc: "2.0", id: 1, method: "pickle_subscribe", params: ["miniBlocks"],
  }));
});

socket.addEventListener("message", (event) => {
  const message = JSON.parse(event.data);
  // The subscribe reply carries an id; notifications carry params.result.
  if (!message.params) return;
  const mini = message.params.result;

  // Decimal numbers, not hex quantities - and microseconds, not seconds.
  console.log(mini.number, mini.transactions.length, mini.timestampUs);
});

// A slow handler is DROPPED from the stream rather than buffered, so do the
// work elsewhere and keep this callback cheap.

Si el socket se cierra, sondee pickle_miniBlockNumber y luego pickle_getMiniBlockByNumber desde la última altura vista. Acote la recuperación - el cliente de referencia recupera como máximo 100 por pasada - o una desconexión larga se convierte en una ráfaga de peticiones contra el presupuesto compartido de lecturas pesadas.

Límites y política de expulsión

Ninguno de estos límites es ajustable por entorno, y el tope de conexiones se aplica en la aceptación: la conexión número 257 se cierra sin trama de error, lo que parece un fallo de red en lugar de un rechazo.

Las llamadas ordinarias por el socket

Any frame that is not a subscribe or unsubscribe is forwarded to the same handler the HTTP port uses, so every method in the reference is callable over the socket.