Menu
I've been working on browser extensions that interact with a local application running a WebSocket server. Safari and Chrome Extensions were very easy to implement, and after some headache getting a feel for FF development, I thought I would be able to implement WebSockets as I had in the other browsers. However I have had some issues.
I understand that I can't directly create a WebSocket in the "main" js file, and so attempted to use workarounds I found on the internet:
https://github.com/canuckistani/Jetpack-Websocket-Example uses a page-worker as a sort of proxy between main and the WebSocket code. When I implement this code, my WebSocket connection immediately errors w/ {"isTrusted":true} as the only information.
I also tried to use a hiddenframe as it appears this is how 1Password deals with websocket communication in their FF Addon, but this also results in the same immediate error.
When I simply open a websocket connection to my server in my normal FF instance, it connects perfectly, but so far, I haven't gotten anything to work from addon.
making pageWorker with:
var pw = pageWorker.Page({
contentUrl: self.data.url('com.html'),
contentScriptFile: self.data.url('com.js')
})
com.html:
<!DOCTYPE HTML>
<html>
<body>
</body>
</html>
com.js:
document.onready = launchCom();
// Could this need to be on ready?
function launchCom() {
console.log("[com.js] launchCom Called");
var wsAvailable = false;
if ("WebSocket" in window) {
console.log("[com.js] Detected Websocket in Window, attempting to open...");
// WebSocket is supported.
ws = new WebSocket('ws://localhost:9001');
wsAvailable = true;
} else {
console.log("[com.js] Websocket is not supported, upgrade your browser!");
}
}
ws.onmessage = function(event) {
console.log(event.data);
}
ws.onopen = function(evt) {
console.log("[com.js] ws opened. evt: " + evt);
}
ws.onerror = function(evt) {
console.log("[com.js] ws error: " + JSON.stringify(evt));
}
Running this results in:
console.log: xxx: [com.js] launchCom Called
console.log: xxx: [com.js] Detected Websocket in Window, attempting to open...
console.log: xxx: [com.js] ws error: {"isTrusted":true}
console.log: xxx: [com.js] ws closed. evt: {"isTrusted":true}
Any help would be greatly appreciated!
954
asked Feb 24 '26 01:02
I've solved the problem:
I'm using https://github.com/zwopple/PocketSocket in my OS X application as my server, and there appears to be an issue with PocketSocket and FF.
After changing PocketSocket's PSWebSocketDriver.m line 87 code from
[[headers[@"Connection"] lowercaseString] isEqualToString:@"upgrade"]
to
[[headers[@"Connection"] lowercaseString] containsString:@"upgrade"]
per https://github.com/zwopple/PocketSocket/issues/34, I was able to open a WebSocket connection from FF addon using the original code, but the server errored on messages.
Setting network.websocket.extensions.permessage-deflate to false in about:config allowed messages to be sent so I added
require("sdk/preferences/service").set("network.websocket.extensions.permessage-deflate", false);
to my main.js and everthing is working!
The tiny change to PocketSocket's code hasn't had any effects on the server interacting with other WebSocket clients.
175
answered Feb 25 '26 15:02
If you love us? You can donate to us via Paypal or buy me a coffee so we can maintain and grow! Thank you!
Donate Us With