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版本：4.x

Version 4.5.0

April 23, 2022

Server​

Bug Fixes​

  • typings: ensure compatibility with TypeScript 3.x (#4259) (02c87a8)

Features​

Catch-all listeners for outgoing packets​

This is similar to onAny(), but for outgoing packets.

Syntax:

socket.onAnyOutgoing((event, ...args) => {
  console.log(event);
});

Added in 531104d.

Broadcast and expect multiple acknowledgements​

Syntax:

io.timeout(1000).emit("some-event", (err, responses) => {
  // ...
});

Added in 8b20457.

maxHttpBufferSize value negotiation​

A "maxPayload" field is now included in the Engine.IO handshake, so that clients in HTTP long-polling can decide how many packets they have to send to stay under the maxHttpBufferSize value.

This is a backward compatible change which should not mandate a new major revision of the protocol (we stay in v4), as we only add a field in the JSON-encoded handshake data:

0{"sid":"lv_VI97HAXpY6yYWAAAC","upgrades":["websocket"],"pingInterval":25000,"pingTimeout":5000,"maxPayload":1000000}

Added in 088dcb4.

Dependencies​

Client​

Features​

Additional details for the disconnect event​

The "disconnect" event will now include additional details to help debugging if anything has gone wrong.

Example when a payload is over the maxHttpBufferSize value in HTTP long-polling mode:

socket.on("disconnect", (reason, details) => {
  console.log(reason); // "transport error"

  // in that case, details is an error object
  console.log(details.message); "xhr post error"
  console.log(details.description); // 413 (the HTTP status of the response)

  // details.context refers to the XMLHttpRequest object
  console.log(details.context.status); // 413
  console.log(details.context.responseText); // ""
});

Added in b862924.

Catch-all listeners for outgoing packets​

This is similar to onAny(), but for outgoing packets.

Syntax:

socket.onAnyOutgoing((event, ...args) => {
  console.log(event);
});

Added in 74e3e60.

Slice write buffer according to the maxPayload value​

The server will now include a "maxPayload" field in the handshake details, allowing the clients to decide how many packets they have to send to stay under the maxHttpBufferSize value.

Added in 46fdc2f.

Dependencies​