From d892c9e7348770f29b135e7a113ca662c8a1fa19 Mon Sep 17 00:00:00 2001
From: Cory McWilliams <cory@unprompted.com>
Date: Sun, 19 Jun 2022 18:01:21 +0000
Subject: [PATCH] Add a helper for app <-> browser communication.

git-svn-id: https://www.unprompted.com/svn/projects/tildefriends/trunk@3908 ed5197a5-7fde-0310-b194-c3ffbd925b24
---
 core/client.js |  2 +-
 core/core.js   |  4 ++-
 core/tfrpc.js  | 78 ++++++++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 82 insertions(+), 2 deletions(-)
 create mode 100644 core/tfrpc.js

diff --git a/core/client.js b/core/client.js
index 0e48996b..b911aa0d 100644
--- a/core/client.js
+++ b/core/client.js
@@ -410,7 +410,7 @@ function api_error(error) {
 		if (typeof(error) == 'string') {
 			setStatusMessage('⚠️ ' + error, '#f00');
 		} else {
-			setStatusMessage('⚠️ ' + merror.message + '\n' + error.stack, '#f00');
+			setStatusMessage('⚠️ ' + error.message + '\n' + error.stack, '#f00');
 		}
 	}
 	console.log('error', error);
diff --git a/core/core.js b/core/core.js
index 73cb3d77..f04d3c0c 100644
--- a/core/core.js
+++ b/core/core.js
@@ -225,6 +225,7 @@ async function getProcessBlob(blobId, key, options) {
 					var id = appObject.files[appSourceName];
 					var blob = await getBlobOrContent(id);
 					appSource = utf8Decode(blob);
+					await process.task.loadFile(['/tfrpc.js', await File.readFile('core/tfrpc.js')]);
 					await Promise.all(Object.keys(appObject.files).map(async function(f) {
 						await process.task.loadFile([f, await getBlobOrContent(appObject.files[f])]);
 					}));
@@ -264,6 +265,7 @@ var kStaticFiles = [
 	{uri: '/style.css', type: 'text/css; charset=UTF-8'},
 	{uri: '/favicon.png', type: 'image/png'},
 	{uri: '/client.js', type: 'text/javascript; charset=UTF-8'},
+	{uri: '/tfrpc.js', type: 'text/javascript; charset=UTF-8', headers: {'Access-Control-Allow-Origin': 'null'}},
 	{uri: '/robots.txt', type: 'text/plain; charset=UTF-8'},
 ];
 
@@ -285,7 +287,7 @@ async function staticFileHandler(request, response, blobId, uri) {
 			var path = kStaticFiles[i].path || uri.substring(1);
 			var type = kStaticFiles[i].type || guessType(path);
 			var data = await File.readFile("core/" + path);
-			response.writeHead(200, {"Content-Type": type, "Content-Length": data.byteLength});
+			response.writeHead(200, Object.assign({"Content-Type": type, "Content-Length": data.byteLength}, kStaticFiles[i].headers || {}));
 			response.end(data);
 			return;
 		}
diff --git a/core/tfrpc.js b/core/tfrpc.js
new file mode 100644
index 00000000..79dfc2cc
--- /dev/null
+++ b/core/tfrpc.js
@@ -0,0 +1,78 @@
+const k_is_browser = get_is_browser();
+let g_api = {};
+let g_next_id = 1;
+let g_calls = {};
+
+function get_is_browser() {
+	try { return window !== undefined && console !== undefined; } catch { return false; }
+}
+
+if (k_is_browser) {
+	print = console.log;
+}
+
+function make_rpc(target, prop, receiver) {
+	return function() {
+		let id = g_next_id++;
+		let promise = new Promise(function(resolve, reject) {
+			g_calls[id] = {resolve: resolve, reject: reject};
+		});
+		if (k_is_browser) {
+			window.parent.postMessage({message: 'tfrpc', method: prop, params: [...arguments], id: id}, '*');
+			return promise;
+		} else {
+			return app.postMessage({message: 'tfrpc', method: prop, params: [...arguments], id: id}).then(x => promise);
+		}
+	}
+}
+
+function call_rpc(message) {
+	if (message && message.message === 'tfrpc') {
+		if (message.method) {
+			let method = g_api[message.method];
+			if (method) {
+				let response = {message: 'tfrpc', id: message.id};
+				try {
+					response.result = method(...message.params);
+				} catch (error) {
+					response.error = error;
+				}
+				if (k_is_browser) {
+					window.parent.postMessage(response, '*');
+				} else {
+					app.postMessage(response);
+				}
+			} else {
+				throw new Error(message.method + ' not found.');
+			}
+		} else if (message.result !== undefined) {
+			if (g_calls[message.id]) {
+				g_calls[message.id].resolve(message.result);
+			} else {
+				throw new Error(message.id + ' not found to reply.');
+			}
+		} else if (message.error !== undefined) {
+			if (g_calls[message.id]) {
+				g_calls[message.id].reject(message.error);
+			} else {
+				throw new Error(message.id + ' not found to reply.');
+			}
+		}
+	}
+}
+
+if (k_is_browser) {
+	window.addEventListener('message', function(event) {
+		call_rpc(event.data);
+	});
+} else {
+	core.register('message', function(message) {
+		call_rpc(message?.message);
+	});
+}
+
+export let rpc = new Proxy({}, {get: make_rpc});
+
+export function register(method) {
+	g_api[method.name] = method;
+}