Extension Manifest V3 support is now available

[samuelmaddock]

Features required for Manifest V3 support have been proposed in Electron upstream. Once other maintainers have reviewed and accepted the changes, it will be ready to use.
electron/electron#44411

---

Manifest V3 (MV3) is that latest versions of the Chrome extensions API which is now stable in Chrome.

It's partially supported in Electron at the moment since electron/electron#27562 was introduced.

Known affected extensions

I don't know of any widely used extensions shipping with MV3 yet, but there will be as MV2 begins to be phased out.

Possible solutions

electron-chrome-extensions provides new extension APIs by injecting them with JavaScript. This is done in Electron preload scripts. Instead of background hosts using a WebContents instance, MV3 uses service workers.

Electron doesn't have support for injecting JS into a service worker context yet. The API will need to be expanded to support new contexts. Work on specing out changes has started in electron/governance#366

[schetle]

Is there any news on electron's support for injecting JS into service worker contexts?

https://developer.chrome.com/docs/extensions/mv3/mv2-sunset/

Here's the V2 support timeline, and so we're looking to get upgraded to V3 before V2 is completely killed off.

[samuelmaddock]

Is there any news on electron's support for injecting JS into service worker contexts?

Currently no update. I've spent time researching what it would take and the amount of work is non-trivial.

Electron's preload scripts work in a secure environment thanks to the effort of extension content scripts which provide an isolated JS context. Node's globals and other variables within preload scripts are separate from the main JS context. This is how V8's binding system works: https://chromium.googlesource.com/chromium/src/+/master/third_party/blink/renderer/bindings/core/v8/V8BindingDesign.md#world

The problem is when trying to do the same thing with Workers (Service, Web, Shared). Support for isolated worlds/contexts within a worker environment isn't something that exists yet. This has been attempted before without context isolation which isn't a secure approach (see electron/electron#28923 (comment)).

At a high-level, here's a list of what might be needed:

• Create new v8::Context in the renderer's Worker Thread to run alongside global service worker contexts
• Inject node into the new context
• Use internals of the contextBridge API to provide a bridge between the worker preload context and the service worker context
• Provide API for executing JS in the main worker context from the preload context; ie. worker.executeScript(js)

Then there's a few other requirements just for API design within Electron. A design proposal might be needed for that in the API governance repo.

I do realize the importance of this work prior to Chrome dropping support of MV2, however, I don't currently have a roadmap for these contributions.

[lengband]

@samuelmaddock hello. May I know the current status of this matter? Is there any news on electron's support for injecting JS into service worker contexts?
i am using electron-chrome-extensions but it only supports V2.

[samuelmaddock]

Electron does not yet support preload scripts for service workers. I'm not aware of others currently working towards adding this.

I spent time on it a couple of months ago, but I have no estimate and I'm not close to a solution.

[PascalPixel]

In case anyone is interested, there is movement towards Manifest v3; electron/electron#39395

[ductridev]

any updates on this :(

[samuelmaddock]

I'm currently awaiting comments on my RFC which would unblock this
electron/rfcs#4