When a player disconnects, fail all unresolved requests that were sent to that player

CHANGELOG.md

@@ -5,6 +5,7 @@
 
 ### Bugfixes
 - When an invalid user id is specified socketlib will now throw the correct error message.
+- When a player disconnects the moment an execution has been scheduled for their client the execution function will now throw an exception, as it would if the player hadn't been connected in the first place. Previously the execution would just silently fail and the promise never resolve in such cases.
 
 
 ## 1.0.3

module.json

@@ -14,6 +14,7 @@
 		}
 	],
 	"esmodules": [
+		"src/libwrapper_shim.js",
 		"src/socketlib.js"
 	],
 	"url": "https://github.com/manuelVo/foundryvtt-socketlib",

src/libwrapper_shim.js

@@ -0,0 +1,61 @@
+// SPDX-License-Identifier: MIT
+// Copyright © 2021 fvtt-lib-wrapper Rui Pinheiro
+
+'use strict';
+
+// A shim for the libWrapper library
+export let libWrapper = undefined;
+
+Hooks.once('init', () => {
+	// Check if the real module is already loaded - if so, use it
+	if(globalThis.libWrapper && !(globalThis.libWrapper.is_fallback ?? true)) {
+		libWrapper = globalThis.libWrapper;
+		return;
+	}
+
+	// Fallback implementation
+	libWrapper = class {
+		static get is_fallback() { return true };
+
+		static register(module, target, fn, type="MIXED", {chain=undefined}={}) {
+			const is_setter = target.endsWith('#set');
+			target = !is_setter ? target : target.slice(0, -4);
+			const split = target.split('.');
+			const fn_name = split.pop();
+			const root_nm = split.splice(0,1)[0];
+			const _eval = eval; // The browser doesn't expose all global variables (e.g. 'Game') inside globalThis, but it does to an eval. We copy it to a variable to have it run in global scope.
+			const obj = split.reduce((x,y)=>x[y], globalThis[root_nm] ?? _eval(root_nm));
+
+			let iObj = obj;
+			let descriptor = null;
+			while(iObj) {
+				descriptor = Object.getOwnPropertyDescriptor(iObj, fn_name);
+				if(descriptor) break;
+				iObj = Object.getPrototypeOf(iObj);
+			}
+			if(!descriptor || descriptor?.configurable === false) throw `libWrapper Shim: '${target}' does not exist, could not be found, or has a non-configurable descriptor.`;
+
+			let original = null;
+			const wrapper = (chain ?? type != 'OVERRIDE') ? function() { return fn.call(this, original.bind(this), ...arguments); } : function() { return fn.apply(this, arguments); };
+
+			if(!is_setter) {
+				if(descriptor.value) {
+					original = descriptor.value;
+					descriptor.value = wrapper;
+				}
+				else {
+					original = descriptor.get;
+					descriptor.get = wrapper;
+				}
+			}
+			else {
+				if(!descriptor.set) throw `libWrapper Shim: '${target}' does not have a setter`;
+				original = descriptor.set;
+				descriptor.set = wrapper;
+			}
+
+			descriptor.configurable = true;
+			Object.defineProperty(obj, fn_name, descriptor);
+		}
+	}
+});

src/socketlib.js

@@ -1,3 +1,4 @@
+import {libWrapper} from "./libwrapper_shim.js";
 import * as errors from "./errors.js";
 
 const RECIPIENT_TYPES = {
@@ -17,8 +18,9 @@ const MESSAGE_TYPES = {
 
 Hooks.once("init", () => {
 	window.socketlib = new Socketlib();
+	libWrapper.register("socketlib", "Users.prototype.constructor._handleUserActivity", handleUserActivity);
 	Hooks.callAll("socketlib.ready");
-});
+}, "WRAPPER");
 
 class Socketlib {
 	constructor() {
@@ -88,7 +90,7 @@ class SocketlibSocket {
 			return this._executeLocal(func, ...args);
 		}
 		else {
-			if (!game.users.find(user => user.isGM && user.active)) {
+			if (!game.users.find(isActiveGM)) {
 				throw new errors.SocketlibNoGMConnectedError(`Could not execute handler '${name}' (${func.name}) as GM, because no GM is connected.`);
 			}
 			return this._sendRequest(name, args, RECIPIENT_TYPES.ONE_GM);
@@ -304,6 +306,48 @@ class SocketlibSocket {
 function isResponsibleGM() {
 	if (!game.user.isGM)
 		return false;
-	const connectedGMs = game.users.filter(user => user.isGM && user.active);
+	const connectedGMs = game.users.filter(isActiveGM);
 	return !connectedGMs.some(other => other.data._id < game.user.data._id);
 }
+
+function isActiveGM(user) {
+	return user.active && user.isGM;
+}
+
+function handleUserActivity(wrapper, userId, activityData={}) {
+	const user = game.users.get(userId);
+	const wasActive = user.active;
+	const result = wrapper(userId, activityData);
+
+	// If user disconnected
+	if (!user.active && wasActive) {
+		const modules = Array.from(socketlib.modules.values());
+		if (socketlib.system)
+			modules.concat(socketlib.system);
+		const GMConnected = Boolean(game.users.find(isActiveGM));
+		// Reject all promises that are still waiting for a response from this player
+		for (const socket of modules) {
+			const failedRequests = Array.from(socket.pendingRequests.entries()).filter(([id, request]) => {
+				const recipient = request.recipient;
+				const handlerName = request.handlerName;
+				if (recipient === RECIPIENT_TYPES.ONE_GM) {
+					if (!GMConnected) {
+						request.reject(new errors.SocketlibNoGMConnectedError(`Could not execute handler '${handlerName}' as GM, because all GMs disconnected while the execution was being dispatched.`));
+						return true;
+					}
+				}
+				else if (recipient instanceof Array) {
+					if (recipient.includes(userId)) {
+						request.reject(new errors.SocketlibInvalidUserError(`User '${game.users.get(userId).name}' (${userId}) disconnected while handler '${handlerName}' was being dispatched.`));
+						return true;
+					}
+				}
+				return false;
+			});
+			for (const [id, request] of failedRequests) {
+				socket.pendingRequests.delete(id);
+			}
+		}
+	}
+	return result;
+}