From 13b59dacb2cd8f907eaba6b97f927b72f02fe672 Mon Sep 17 00:00:00 2001
From: toasted-nutbread <toasted-nutbread@users.noreply.github.com>
Date: Sun, 31 May 2020 18:19:53 -0400
Subject: Limit action port message size (#587)

* Add onDisconnect handler

* Update how error is posted

* Update action ports to send long messages in fragments

* Remove ack timer

* Move message destructuring into try block
---
 ext/mixed/js/api.js | 26 +++++++++-----------------
 1 file changed, 9 insertions(+), 17 deletions(-)

(limited to 'ext/mixed/js')

diff --git a/ext/mixed/js/api.js b/ext/mixed/js/api.js
index 0bc91759..d2be12aa 100644
--- a/ext/mixed/js/api.js
+++ b/ext/mixed/js/api.js
@@ -204,7 +204,6 @@ function _apiCreateActionPort(timeout=5000) {
 
 function _apiInvokeWithProgress(action, params, onProgress, timeout=5000) {
     return new Promise((resolve, reject) => {
-        let timer = null;
         let port = null;
 
         if (typeof onProgress !== 'function') {
@@ -213,12 +212,6 @@ function _apiInvokeWithProgress(action, params, onProgress, timeout=5000) {
 
         const onMessage = (message) => {
             switch (message.type) {
-                case 'ack':
-                    if (timer !== null) {
-                        clearTimeout(timer);
-                        timer = null;
-                    }
-                    break;
                 case 'progress':
                     try {
                         onProgress(...message.data);
@@ -243,10 +236,6 @@ function _apiInvokeWithProgress(action, params, onProgress, timeout=5000) {
         };
 
         const cleanup = () => {
-            if (timer !== null) {
-                clearTimeout(timer);
-                timer = null;
-            }
             if (port !== null) {
                 port.onMessage.removeListener(onMessage);
                 port.onDisconnect.removeListener(onDisconnect);
@@ -256,17 +245,20 @@ function _apiInvokeWithProgress(action, params, onProgress, timeout=5000) {
             onProgress = null;
         };
 
-        timer = setTimeout(() => {
-            cleanup();
-            reject(new Error('Timeout'));
-        }, timeout);
-
         (async () => {
             try {
                 port = await _apiCreateActionPort(timeout);
                 port.onMessage.addListener(onMessage);
                 port.onDisconnect.addListener(onDisconnect);
-                port.postMessage({action, params});
+
+                // Chrome has a maximum message size that can be sent, so longer messages must be fragmented.
+                const messageString = JSON.stringify({action, params});
+                const fragmentSize = 1e7; // 10 MB
+                for (let i = 0, ii = messageString.length; i < ii; i += fragmentSize) {
+                    const data = messageString.substring(i, i + fragmentSize);
+                    port.postMessage({action: 'fragment', data});
+                }
+                port.postMessage({action: 'invoke'});
             } catch (e) {
                 cleanup();
                 reject(e);
-- 
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