README.md

Surge.jl

A package that exposes reactive state via WebSockets, enabling real-time synchronization between Julia backends and web clients. It uses StateSignals.jl for managing reactive states, and exposes their values via websockets.

You can find here a demo application with a Surge.jl backend and a VueJS frontend. See it live here with a VueJS frontend.

Example

Define some signals and start the server:

using Surge: Signal, computed, effect, start_server

counter = Signal(0,:counter)
countertwo = Signal(6,:countertwo)
total = computed(() -> counter() + countertwo(), :total)
word = Signal("hello", :word)


effect(() -> println("Counter updated to ", counter()))
effect(() -> println("Countertwo updated to ", countertwo()))
effect(() -> println("Total is ", total()))


server = start_server([counter, countertwo, total, word], 8080)

You can now send websocket messages as

using HTTP.WebSockets
using JSON

WebSockets.open("ws://localhost:8080'") do ws
    # Send an update message
    update_msg = JSON.json(Dict(
        "type" => "update",
        "id" => "counter",  # matches the signal ID
        "value" => 42
    ))
    WebSockets.send(ws, update_msg)

    response = String(WebSockets.receive(ws))
    println("Received: ", response)
end

You'll see in the REPL that the effects are triggered and the total is updated.