vue-signalr

A Vue3 plugin which wraps SignalR and provider stricter typings.

Installation

Install this package and SignalR peer dependency

$ yarn add @dreamonkey/vue-signalr @microsoft/signalr

Apply the plugin providing a HubConnection instance

import { VueSignalR } from "@dreamonkey/vue-signalr";
import { HubConnectionBuilder } from "@microsoft/signalr";
import { createApp } from "vue";
import App from "./App.vue";

// Create your connection
// See https://docs.microsoft.com/en-us/javascript/api/@microsoft/signalr/hubconnectionbuilder
const connection = new HubConnectionBuilder()
  .withUrl("http://localhost:5000/signalr")
  .build();

createApp(App).use(VueSignalR, { connection }).mount("#app");

Usage

import { useSignalR } from "@dreamonkey/vue-signalr";
import { inject } from "vue";

export default {
  setup() {
    const signalr = useSignalR();

    signalr.invoke("SendMessage", { message });

    signalr.on("MessageReceived", ({ message }) => {
      /* do stuff */
    });
  },
};

While SignalR doesn't make a distinction between client side and server side methods, into this package we refer the formers as "Events" and the latters as "Commands".

Commands can be sent using signalr.invoke(), while events can be enabled or disabled using signalr.on() and signalr.off()

Unsubscribing

All Event you create a listener for using signalr.on() must be unsubscribed when not used anymore, to avoid memory leaks and erratic code behavior. If you call signalr.on() within a Vue component setup scope, the listener will be unsubscribed automatically into onBeforeUnmount hook. This behavior can be disabled via autoOffInsideComponentScope plugin option.

If you disabled it, or you start a listener outside a component scope, you'll need to unsubscribe it manually using signal.off() and providing the same listener function reference to it. Not providing it will remove all listeners from the provided Event

const messageReceivedCallback = (message) => console.log(message.prop);

signalr.on("MessageReceived", messageReceivedCallback);

signalr.off("MessageReceived", messageReceivedCallback); // Remove this listener
signalr.off("MessageReceived"); // Remove all listeners on `MessageReceived` event

Type-safety

Command and Events names and payloads are registered via type augmentation of dedicated interfaces (SignalREvents and SignalRCommands) into @dreamonkey/vue-signalr scope. These types are later used to provide you autocompletion.

The package works with plain strings too, you're not required to register Commands/Events typings

import "@dreamonkey/vue-signalr";

interface MessageReceivedPayload {
  message: string;
}

interface SendMessagePayload {
  message: string;
}

declare module "@dreamonkey/vue-signalr" {
  interface SignalREvents {
    // Define an event, its payload is a single parameter of type `MessageReceivedPayload`
    MessageReceived: MessageReceivedPayload;
    // Define an event, its payload is composed by 0 or more parameters of type `MessageReceivedPayload`
    MultipleMessagesReceived: MessageReceivedPayload[];
    // Define an event, its payload is composed by exactly 2 parameters of type `MessageReceivedPayload`
    TwoMessagesReceived: [MessageReceivedPayload, MessageReceivedPayload];
    // Define an event with no payload
    MainTopicJoined: false;
  }

  interface SignalRCommands {
    // Define a command and its payload
    SendMessage: SendMessagePayload;
    // Define a command with no payload
    JoinMainTopic: false;
  }
}

Methods remapping

In case you need to remap a Command or Event name, you could do so using remapMethod or remapMethods helpers

import { remapMethod } from "@dreamonkey/vue-signalr";

remapMethod("receiveMessageWithStrangeMethodName", "MessageReceived");

remapMethods([
  ["legacyTopic2Joined", "MainTopicJoined"],
  ["createNewMessage", "SendMessage"],
]);

Error Handling

You can react to connection/reconnection errors providing a failFn option into the plugin options

import { VueSignalR } from "@dreamonkey/vue-signalr";
import { createApp } from "vue";
import App from "./App.vue";

const connection = new HubConnectionBuilder()
  .withUrl("http://localhost:5000/signalr")
  .build();

createApp(App)
  .use(VueSignalR, {
    connection,
    failFn: () => {
      /* do stuff */
    },
  })
  .mount("#app");

Possible next steps

• take inspiration from other helpers into https://socket.io/docs/v4/listening-to-events/
• take inspiration from other features at the end of https://socket.io/docs/v4/how-it-works/
• add rooms join/leave abstractions (?)

Credits

This package has been inspired by https://github.com/quangdaon/vue-signalr