Block images from particular domain in GeckoView android

How can i block image loading from specific domain in GeckoView? I tried searching equitant method like setLoadsImagesAutomatically from webview in GeckoView but no luck. I found few links like this and this. Can we block image loading by injecting javaScript in GeckoView?

Answer

You can register a system WebExtension using installBuiltIn that uses webRequest.onBeforeRequest to block loading images from a given domain, or really any other criteria.

Example:

Create a folder under /assets/ for your extension, e.g. /assets/block-images and add a manifest.json and background.js files like this:

manifest.json

{
  "manifest_version": 2,
  "name": "block-images",
  "version": "1.0",
  "description": "Block images from mozilla.org",
  "browser_specific_settings": {
    "gecko": {
      "id": "[e-mail]"
    }
  },
  "permissions": [
    "*://*.mozilla.org/*",
    "webRequest",
    "webRequestBlocking"
  ],
  "background": {
    "scripts": ["background.js"]
  }
}

background.js

"use strict";

function listener(details) {
  // blocks all images from twitter.com
  return {cancel: true};
}

browser.webRequest.onBeforeRequest.addListener(
  listener,
  {urls: ["*://*.mozilla.org/*"], types: ["image"]},
  ["blocking"]
);

Then you can install the extension at startup somewhere using ensureBuiltIn:

  runtime
      .getWebExtensionController()
      .ensureBuiltIn(
          "resource://android/assets/block-images/",
          "[e-mail]");

And after that any page that you load in GeckoView will block images to mozilla.org as defined in the background.js file.