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Version: 4.x

适配器

适配器是一个服务器端组件，负责向所有或部分客户端广播事件。

¥An Adapter is a server-side component which is responsible for broadcasting events to all or a subset of clients.

当扩展到多个 Socket.IO 服务器时，你将需要用另一种实现替换默认的内存适配器，以便事件正确路由到所有客户端。

¥When scaling to multiple Socket.IO servers, you will need to replace the default in-memory adapter by another implementation, so the events are properly routed to all clients.

以下是我们团队维护的适配器列表：

¥Here is the list of adapters that are maintained by our team:

还有其他几个由（太棒了！）社区维护的选项：

¥There are also several other options which are maintained by the (awesome!) community:

请注意，当使用多个 Socket.IO 服务器和 HTTP 长轮询时，仍然需要启用粘性会话。更多信息在 此处。

¥Please note that enabling sticky sessions is still needed when using multiple Socket.IO servers and HTTP long-polling. More information here.

API​

你可以通过以下方式访问适配器实例：

¥You can have access to the adapter instance with:

// main namespace
const mainAdapter = io.of("/").adapter; // WARNING! io.adapter() will not work
// custom namespace
const adminAdapter = io.of("/admin").adapter;

从 socket.io@3.1.0 开始，每个 Adapter 实例都会触发以下事件：

¥Starting with socket.io@3.1.0, each Adapter instance emits the following events:

  • create-room（参数：房间）

    ¥create-room (argument: room)

  • delete-room（参数：房间）

    ¥delete-room (argument: room)

  • join-room（参数：房间、id）

    ¥join-room (argument: room, id)

  • leave-room（参数：房间、id）

    ¥leave-room (argument: room, id)

示例：

¥Example:

io.of("/").adapter.on("create-room", (room) => {
  console.log(`room ${room} was created`);
});

io.of("/").adapter.on("join-room", (room, id) => {
  console.log(`socket ${id} has joined room ${room}`);
});

触发器​

¥Emitter

大多数适配器实现都附带其关联的触发器包，该包允许从另一个 Node.js 进程与 Socket.IO 服务器组进行通信。

¥Most adapter implementations come with their associated emitter package, which allows communicating to the group of Socket.IO servers from another Node.js process.

Emitter diagramEmitter diagram

例如，这在微服务设置中可能很有用，其中所有客户端都连接到微服务 M1，而微服务 M2 使用触发器广播数据包（单向通信）。

¥This may be useful for example in a microservice setup, where all clients connect to the microservice M1, while the microservice M2 uses the emitter to broadcast packets (uni-directional communication).

触发器备忘单​

¥Emitter cheatsheet

// to all clients
emitter.emit(/* ... */);

// to all clients in "room1"
emitter.to("room1").emit(/* ... */);

// to all clients in "room1" except those in "room2"
emitter.to("room1").except("room2").emit(/* ... */);

const adminEmitter = emitter.of("/admin");

// to all clients in the "admin" namespace
adminEmitter.emit(/* ... */);

// to all clients in the "admin" namespace and in the "room1" room
adminEmitter.to("room1").emit(/* ... */);

触发器还支持 socket.io@4.0.0 中添加的实用方法：

¥The emitter also supports the utility methods that were added in socket.io@4.0.0:

  • socketsJoin()
// make all Socket instances join the "room1" room
emitter.socketsJoin("room1");

// make all Socket instances of the "admin" namespace in the "room1" room join the "room2" room
emitter.of("/admin").in("room1").socketsJoin("room2");
  • socketsLeave()
// make all Socket instances leave the "room1" room
emitter.socketsLeave("room1");

// make all Socket instances in the "room1" room leave the "room2" and "room3" rooms
emitter.in("room1").socketsLeave(["room2", "room3"]);

// make all Socket instances in the "room1" room of the "admin" namespace leave the "room2" room
emitter.of("/admin").in("room1").socketsLeave("room2");
  • disconnectSockets()
// make all Socket instances disconnect
emitter.disconnectSockets();

// make all Socket instances in the "room1" room disconnect (and discard the low-level connection)
emitter.in("room1").disconnectSockets(true);

// make all Socket instances in the "room1" room of the "admin" namespace disconnect
emitter.of("/admin").in("room1").disconnectSockets();

// this also works with a single socket ID
emitter.of("/admin").in(theSocketId).disconnectSockets();
  • serverSideEmit()
// emit an event to all the Socket.IO servers of the cluster
emitter.serverSideEmit("hello", "world");

// Socket.IO server (server-side)
io.on("hello", (arg) => {
  console.log(arg); // prints "world"
});