setDiscoverTargets is not allowed for chrome extension - google-chrome

Question

I am trying to develop a chrome extension and in this extension, I need the target related events (targetCreated/targetInfoChanged/targetDestroyed).
To achieve that goal I am using setDiscoverTargets method from the devtools protocol by means of chrome.debugger API. Here is the pseudocode that I am using:
// attach the debugger
chrome.debugger.attach(debuggeeId, version, onAttach);
// when attach is successful send setAuthAttach to make setDiscoverTargets command work
const onAttach = (debuggeeId) => {
if (chrome.runtime.lastError) {
alert(chrome.runtime.lastError.message);
return;
}
console.log(`onAttach: ${JSON.stringify(debuggeeId)}`);
chrome.debugger.sendCommand({ tabId: myTabId }, "Target.setAutoAttach", { autoAttach: false, waitForDebuggerOnStart: false, flatten: true }, setAutoAttachHandler);
}
// when auto attach handler is successful send setDiscoverTargets method
// to enable targetCreated/targetInfoChanged/targetDestroyed events
const setAutoAttachHandler = (result) => {
if (chrome.runtime.lastError) {
console.log("error in setAutoAttachHandler:" + chrome.runtime.lastError.message);
return;
}
console.log(`setAutoAttachHandler result: ${JSON.stringify(result)}`);
chrome.debugger.sendCommand({ tabId: myTabId }, 'Target.setDiscoverTargets', { discover: true }, setDiscoverTargetsHandler);
}
// see the result of command
const setDiscoverTargetsHandler = (result) => {
if (chrome.runtime.lastError) {
console.log("error in setDiscoverTargetsHandler:" + chrome.runtime.lastError.message);
return;
}
console.log(`setDiscoverTargets result: ${JSON.stringify(result)}`);
}
As per execute the code above I am always getting not allowed error
error in setDiscoverTargetsHandler:{"code":-32000,"message":"Not
allowed"}
And the events related to the target are not fired. Is there anything else I should do to get those events?
thank you.

Answer 1

Methods under Target and Browser domain(except for Browser.getVersion) are not allowed when sending command from chrome.debugger api. But if you want to observe for tabs to which debugger is attached or tabs in which developer tools is opened then you can poll chrome.debugger.getTargets at regular intervals. You will get response, something like this :-
[{
"attached": true,
"faviconUrl": "https://www.wikipedia.org/static/favicon/wikipedia.ico",
"id": "DEA9ED6A4A3DFB9A6FC315AF7110465B",
"tabId": 88,
"title": "Wikipedia",
"type": "page",
"url": "https://www.wikipedia.org/,
}, {
"attached": false,
"faviconUrl": "https://github.githubassets.com/favicons/favicon.svg",
"id": "3314432045C3EC141D4C7D7023606122",
"tabId": 87,
"title": "GitHub",
"type": "page",
"url": "https://github.com/"
}]