Chrome extensions - Other ways to read response bodies than chrome.devtools.network?

Question

I'd like to read (not modify) the response body for all requests that match some pattern in a Chrome extension. I'm currently using chrome.devtools.network.onRequestFinished, which gives you a Request object with a getContent() method. This works just fine, but of course requires the devtools to be open for the extension to work. Ideally the extension would be a popup, but chrome.webRequest.onCompleted doesn't seem to give access to the response body. There is a feature request to allow the webRequest API to edit response bodies - but can webRequest even read them? If not, is there any other way to read response bodies outside of devtools extensions?

Answer 1

The feature request you linked to implies that there is no support for reading either:

Unfortunately, this request is not trivial. (...) Regarding reading the Response Body: This is challenging from a performance perspective. (...) So overall, this is just not easy to achieve...

So, no, there doesn't seem to be a way for an extension to access network response bodies, except for devtools.