Intercepting HTTP requests doesn't work

Add-ons Development
1

Hi, I’m trying to build a simple extension to intercept HTTP requests. My Firefox version is 140.7.0 ESR.

I follow this article: Intercept HTTP requests - Mozilla | MDN

Basically, I’ve copy-pasted the content of manifest.json and background.js files from the above article. Then I loaded the extension in the about:debugging page. The extension should print URLs into the console but when I click links on pages nothing happens.

Here’s manifest.json:

{
  "description": "Demonstrating webRequests",
  "manifest_version": 2,
  "name": "webRequest-demo",
  "version": "1.0",

  "permissions": ["webRequest", "<all_urls>"],

  "background": {
    "scripts": ["background.js"]
  }
}

And background.js:

function logURL(requestDetails) {
  console.log(`Loading: ${requestDetails.url}`);
}

browser.webRequest.onBeforeRequest.addListener(logURL, {
  urls: ["<all_urls>"],
});

I’m not sure what is going wrong as this is my first attempt to write an extension.

2

Do you have correct console open?
These logs are printed only the background script console.
You can open it from the about:debugging page by clicking the Inspect button next to your addon:

image
image947×392 33.7 KB

3

That worked, thank you!