fnx_web/svelte/src/lib/StatsSocket.js

import { readable } from "svelte/store";

let results = {
	connected: false,
	file_stats_init: false,
	file_stats: {
		views: 0,
		downloads: 0,
		bandwidth: 0,
		bandwidth_paid: 0,
	},
	limits_init: false,
	limits: {
		server_overload: false,
		speed_limit: 0,
		download_limit: 0,
		download_limit_used: 0,
		transfer_limit: 0,
		transfer_limit_used: 0,
	},
}

export const stats = readable(
	results,
	(set) => {
		start_sock(set)
		return () => stop_sock(set)
	},
);

let socket = null
const start_sock = (set_func) => {
	if (socket !== null) {
		return
	}

	console.log("initializing stats socket")
	socket = new WebSocket(location.origin.replace(/^http/, 'ws') + "/api/file_stats")

	socket.onopen = () => {
		results.connected = true
		set_func(results)

		// Subscribe to the rate limit feed. This will also process any queued
		// commands built up while the socket was down
		send_cmd({ type: "limits" })
	}
	socket.onmessage = msg => {
		let j = JSON.parse(msg.data)
		console.debug("WS update", j)

		if (j.type === "file_stats") {
			results.file_stats = j.file_stats
			results.file_stats_init = true
			set_func(results)
		} else if (j.type === "limits") {
			results.limits = j.limits
			results.limits_init = true
			set_func(results)
		} else {
			console.error("Unknown ws message type", j.type, "data", msg.data)
		}
	}
	socket.onerror = err => {
		console.error("socket error", err)
		stop_sock(set_func)
		window.setTimeout(() => start_sock(set_func), 2000)
	}
	socket.onclose = () => {
		stop_sock(set_func)
		window.setTimeout(() => start_sock(set_func), 2000)
	}
}

const stop_sock = (set_func) => {
	if (socket === null) {
		return
	}

	// Prevent error handlers from re-initializing the socket
	socket.onerror = null
	socket.onclose = null

	// Close and delete the socket
	socket.close()
	socket = null

	// Reset the state
	results.connected = false
	results.file_stats_init = false
	results.limits_init = false
	set_func(results)
}

export const set_file = file_id => {
	send_cmd({
		type: "file_stats",
		data: { file_id: file_id },
	})
}

let queued_commands = []
const send_cmd = cmd => {
	if (socket !== null && socket.readyState === WebSocket.OPEN) {

		// First empty the queue
		while (queued_commands.length !== 0) {
			socket.send(JSON.stringify(queued_commands.shift()))
		}

		// Send the requested command
		socket.send(JSON.stringify(cmd))
	} else if (cmd !== null) {
		queued_commands.push(cmd)
		console.debug("Socket is closed, command", cmd, "added to queue")
	}
}