The websocket protocol x-afb-ws-json1

/*
 * Copyright (C) 2015-2024 IoT.bzh Company
 * Author: José Bollo <jose.bollo@iot.bzh>
 *
 * SPDX-License-Identifier: MIT
 */
AFB = function(base, initialtoken){

if (typeof base != "object")
	base = { base: base, token: initialtoken };

var initial = {
	base: base.base || "api",
	token: initialtoken || base.token
		|| URLSearchParams(window.location.search).get('access_token')
		|| URLSearchParams(window.location.search).get('token')
		|| "HELLO",
	host: base.host || window.location.host,
	scheme: base.scheme || (window.location.protocol == "https:" ? "wss:" : "ws:"),
	url: base.url || undefined
};

var urlws = initial.url = initial.url || initial.scheme+"//"+initial.host+"/"+initial.base;

/*********************************************/
/****                                     ****/
/****             AFB_context             ****/
/****                                     ****/
/*********************************************/
var AFB_context;
{
	var UUID = undefined;
	var TOKEN = initial.token;

	var context = function(token, uuid) {
		this.token = token;
		this.uuid = uuid;
	}

	context.prototype = {
		get token() {return TOKEN;},
		set token(tok) {if(tok) TOKEN=tok;},
		get uuid() {return UUID;},
		set uuid(id) {if(id) UUID=id;}
	};

	AFB_context = new context();
}
/*********************************************/
/****                                     ****/
/****             AFB_websocket           ****/
/****                                     ****/
/*********************************************/
var AFB_websocket;
{
	var CALL = 2;
	var RETOK = 3;
	var RETERR = 4;
	var EVENT = 5;

	var PROTO1 = "x-afb-ws-json1";

	AFB_websocket = function(on_open, on_abort) {
		var u = urlws, p = '?';
		if (AFB_context.token) {
			u = u + '?x-afb-token=' + AFB_context.token;
			p = '&';
		}
		if (AFB_context.uuid)
			u = u + p + 'x-afb-uuid=' + AFB_context.uuid;
		this.ws = new WebSocket(u, [ PROTO1 ]);
		this.url = u;
		this.pendings = {};
		this.awaitens = {};
		this.counter = 0;
		this.ws.onopen = onopen.bind(this);
		this.ws.onerror = onerror.bind(this);
		this.ws.onclose = onclose.bind(this);
		this.ws.onmessage = onmessage.bind(this);
		this.onopen = on_open;
		this.onabort = on_abort;
	}

	function onerror(event) {
		var f = this.onabort;
		if (f) {
			delete this.onopen;
			delete this.onabort;
			f(this);
		}
		this.onerror && this.onerror(this);
	}

	function onopen(event) {
		var f = this.onopen;
		delete this.onopen;
		delete this.onabort;
		f && f(this);
	}

	function onclose(event) {
		var err = {
			jtype: 'afb-reply',
			request: {
				status:	'disconnected',
				info: 'server hung up'
			}
		};
		for (var id in this.pendings) {
			try { this.pendings[id][1](err); } catch (x) {/*NOTHING*/}
		}
		this.pendings = {};
		this.onclose && this.onclose();
	}

	function fire(awaitens, name, data) {
		var a = awaitens[name];
		if (a)
			a.forEach(function(handler){handler(data, name);});
		var i = name.indexOf("/");
		if (i >= 0) {
			a = awaitens[name.substring(0,i)];
			if (a)
				a.forEach(function(handler){handler(data, name);});
		}
		a = awaitens["*"];
		if (a)
			a.forEach(function(handler){handler(data, name);});
	}

	function reply(pendings, id, ans, offset) {
		if (id in pendings) {
			var p = pendings[id];
			delete pendings[id];
			try { p[offset](ans); } catch (x) {/*TODO?*/}
		}
	}

	function onmessage(event) {
		var obj = JSON.parse(event.data);
		var code = obj[0];
		var id = obj[1];
		var ans = obj[2];
		AFB_context.token = obj[3];
		switch (code) {
		case RETOK:
			reply(this.pendings, id, ans, 0);
			break;
		case RETERR:
			reply(this.pendings, id, ans, 1);
			break;
		case EVENT:
		default:
			fire(this.awaitens, id, ans);
			break;
		}
	}

	function close() {
		this.ws.close();
		this.ws.onopen =
		this.ws.onerror =
		this.ws.onclose =
		this.ws.onmessage =
		this.onopen =
		this.onabort = function(){};
	}

	function call(method, request, callid) {
		return new Promise((function(resolve, reject){
			var id, arr;
			if (callid) {
				id = String(callid);
				if (id in this.pendings)
					throw new Error("pending callid("+id+") exists");
			} else {
				do {
					id = String(this.counter = 4095 & (this.counter + 1));
				} while (id in this.pendings);
			}
			this.pendings[id] = [ resolve, reject ];
			arr = [CALL, id, method, request ];
			if (AFB_context.token) arr.push(AFB_context.token);
			this.ws.send(JSON.stringify(arr));
		}).bind(this));
	}

	function onevent(name, handler) {
		var id = name;
		var list = this.awaitens[id] || (this.awaitens[id] = []);
		list.push(handler);
	}

	AFB_websocket.prototype = {
		close: close,
		call: call,
		onevent: onevent
	};
}
/*********************************************/
/****                                     ****/
/****    EXPORTS                          ****/
/****                                     ****/
/*********************************************/
return {
	context: AFB_context,
	ws: AFB_websocket
};
};