订阅/WebSocket

使用订阅

¥Using Subscriptions

提示

• 有关全栈示例，请查看 /examples/next-prisma-starter-websockets。

  ¥For a full-stack example have a look at /examples/next-prisma-starter-websockets.

• 有关最低限度的 Node.js 示例，请参阅 /示例/独立服务器。

  ¥For a bare-minimum Node.js example see /examples/standalone-server.

添加订阅流程

¥Adding a subscription procedure

server/router.ts
tsx
import { EventEmitter } from 'events';
import { initTRPC } from '@trpc/server';
import { observable } from '@trpc/server/observable';
import { z } from 'zod';
// create a global event emitter (could be replaced by redis, etc)
const ee = new EventEmitter();
const t = initTRPC.create();
export const appRouter = t.router({
  onAdd: t.procedure.subscription(() => {
    // return an `observable` with a callback which is triggered immediately
    return observable<Post>((emit) => {
      const onAdd = (data: Post) => {
        // emit data to client
        emit.next(data);
      };
      // trigger `onAdd()` when `add` is triggered in our event emitter
      ee.on('add', onAdd);
      // unsubscribe function when client disconnects or stops subscribing
      return () => {
        ee.off('add', onAdd);
      };
    });
  }),
  add: t.procedure
    .input(
      z.object({
        id: z.string().uuid().optional(),
        text: z.string().min(1),
      }),
    )
    .mutation(async (opts) => {
      const post = { ...opts.input }; /* [..] add to db */
      ee.emit('add', post);
      return post;
    }),
});

server/router.ts
tsx
import { EventEmitter } from 'events';
import { initTRPC } from '@trpc/server';
import { observable } from '@trpc/server/observable';
import { z } from 'zod';
// create a global event emitter (could be replaced by redis, etc)
const ee = new EventEmitter();
const t = initTRPC.create();
export const appRouter = t.router({
  onAdd: t.procedure.subscription(() => {
    // return an `observable` with a callback which is triggered immediately
    return observable<Post>((emit) => {
      const onAdd = (data: Post) => {
        // emit data to client
        emit.next(data);
      };
      // trigger `onAdd()` when `add` is triggered in our event emitter
      ee.on('add', onAdd);
      // unsubscribe function when client disconnects or stops subscribing
      return () => {
        ee.off('add', onAdd);
      };
    });
  }),
  add: t.procedure
    .input(
      z.object({
        id: z.string().uuid().optional(),
        text: z.string().min(1),
      }),
    )
    .mutation(async (opts) => {
      const post = { ...opts.input }; /* [..] add to db */
      ee.emit('add', post);
      return post;
    }),
});

创建 WebSocket 服务器

¥Creating a WebSocket-server

bash
yarn add ws

bash
yarn add ws

server/wsServer.ts
ts
import { applyWSSHandler } from '@trpc/server/adapters/ws';
import ws from 'ws';
import { appRouter } from './routers/app';
import { createContext } from './trpc';
const wss = new ws.Server({
  port: 3001,
});
const handler = applyWSSHandler({ wss, router: appRouter, createContext });
wss.on('connection', (ws) => {
  console.log(`➕➕ Connection (${wss.clients.size})`);
  ws.once('close', () => {
    console.log(`➖➖ Connection (${wss.clients.size})`);
  });
});
console.log('✅ WebSocket Server listening on ws://localhost:3001');
process.on('SIGTERM', () => {
  console.log('SIGTERM');
  handler.broadcastReconnectNotification();
  wss.close();
});

server/wsServer.ts
ts
import { applyWSSHandler } from '@trpc/server/adapters/ws';
import ws from 'ws';
import { appRouter } from './routers/app';
import { createContext } from './trpc';
const wss = new ws.Server({
  port: 3001,
});
const handler = applyWSSHandler({ wss, router: appRouter, createContext });
wss.on('connection', (ws) => {
  console.log(`➕➕ Connection (${wss.clients.size})`);
  ws.once('close', () => {
    console.log(`➖➖ Connection (${wss.clients.size})`);
  });
});
console.log('✅ WebSocket Server listening on ws://localhost:3001');
process.on('SIGTERM', () => {
  console.log('SIGTERM');
  handler.broadcastReconnectNotification();
  wss.close();
});

将 TRPCClient 设置为使用 WebSocket

¥Setting TRPCClient to use WebSockets

提示

你可以使用 链接 通过 WebSocket 将查询和/或突变路由到 HTTP 传输和订阅。

¥You can use Links to route queries and/or mutations to HTTP transport and subscriptions over WebSockets.

client.ts
tsx
import { createTRPCProxyClient, createWSClient, wsLink } from '@trpc/client';
import type { AppRouter } from '../path/to/server/trpc';
// create persistent WebSocket connection
const wsClient = createWSClient({
  url: `ws://localhost:3001`,
});
// configure TRPCClient to use WebSockets transport
const client = createTRPCProxyClient<AppRouter>({
  links: [
    wsLink({
      client: wsClient,
    }),
  ],
});

client.ts
tsx
import { createTRPCProxyClient, createWSClient, wsLink } from '@trpc/client';
import type { AppRouter } from '../path/to/server/trpc';
// create persistent WebSocket connection
const wsClient = createWSClient({
  url: `ws://localhost:3001`,
});
// configure TRPCClient to use WebSockets transport
const client = createTRPCProxyClient<AppRouter>({
  links: [
    wsLink({
      client: wsClient,
    }),
  ],
});

使用 React

¥Using React

参见 /examples/next-prisma-starter-websockets。

¥See /examples/next-prisma-starter-websockets.

WebSockets RPC 规范

¥WebSockets RPC Specification

你可以通过深入研究 TypeScript 定义来阅读更多详细信息：

¥You can read more details by drilling into the TypeScript definitions:

• /packages/server/src/rpc/envelopes.ts
• /packages/server/src/rpc/codes.ts。

query/mutation

请求

¥Request

ts
{
  id: number | string;
  jsonrpc?: '2.0'; // optional
  method: 'query' | 'mutation';
  params: {
    path: string;
    input?: unknown; // <-- pass input of procedure, serialized by transformer
  };
}

ts
{
  id: number | string;
  jsonrpc?: '2.0'; // optional
  method: 'query' | 'mutation';
  params: {
    path: string;
    input?: unknown; // <-- pass input of procedure, serialized by transformer
  };
}

响应

¥Response

...下面，或者出现错误。

¥... below, or an error.

ts
{
  id: number | string;
  jsonrpc?: '2.0'; // only defined if included in request
  result: {
    type: 'data'; // always 'data' for mutation / queries
    data: TOutput; // output from procedure
  }
}

ts
{
  id: number | string;
  jsonrpc?: '2.0'; // only defined if included in request
  result: {
    type: 'data'; // always 'data' for mutation / queries
    data: TOutput; // output from procedure
  }
}

subscription/subscription.stop

开始订阅

¥Start a subscription

ts
{
  id: number | string;
  jsonrpc?: '2.0';
  method: 'subscription';
  params: {
    path: string;
    input?: unknown; // <-- pass input of procedure, serialized by transformer
  };
}

ts
{
  id: number | string;
  jsonrpc?: '2.0';
  method: 'subscription';
  params: {
    path: string;
    input?: unknown; // <-- pass input of procedure, serialized by transformer
  };
}

如需取消订阅，请致电 subscription.stop

¥To cancel a subscription, call subscription.stop

ts
{
  id: number | string; // <-- id of your created subscription
  jsonrpc?: '2.0';
  method: 'subscription.stop';
}

ts
{
  id: number | string; // <-- id of your created subscription
  jsonrpc?: '2.0';
  method: 'subscription.stop';
}

订阅响应形状

¥Subscription response shape

...下面，或者出现错误。

¥... below, or an error.

ts
{
  id: number | string;
  jsonrpc?: '2.0';
  result: (
    | {
        type: 'data';
        data: TData; // subscription emitted data
      }
    | {
        type: 'started'; // subscription started
      }
    | {
        type: 'stopped'; // subscription stopped
      }
  )
}

ts
{
  id: number | string;
  jsonrpc?: '2.0';
  result: (
    | {
        type: 'data';
        data: TData; // subscription emitted data
      }
    | {
        type: 'started'; // subscription started
      }
    | {
        type: 'stopped'; // subscription stopped
      }
  )
}

错误

¥Errors

参见 https://www.jsonrpc.org/specification#error_object 或 格式错误。

¥See https://www.jsonrpc.org/specification#error_object or Error Formatting.

从服务器到客户端的通知

¥Notifications from Server to Client

{ id: null, type: 'reconnect' }

告诉客户端在关闭服务器之前重新连接。由 wssHandler.broadcastReconnectNotification() 调用。

¥Tells clients to reconnect before shutting down the server. Invoked by wssHandler.broadcastReconnectNotification().