onibrowser/zombie-lord/adblocking/blockAds.js

A browser in the browser

import {URL} from 'url';
import BLOCKING from './blocking.js';
import {BLOCKED_BODY, BLOCKED_CODE, BLOCKED_HEADERS} from './blockedResponse.js';

export async function blockAds(zombie, sessionId) {
  // do nothing
}

export async function onInterceptRequest({sessionId, message}, zombie) {
  if ( message.method == "Fetch.requestPaused" ) {
    const {request:{url}, requestId, resourceType} = message.params;
    const isNavigationRequest = resourceType == "Document";
    const host = new URL(url).host;
    let blocked = false;
    for( const regex of BLOCKING ) {
      if ( regex.test(host) ) {
        try {
          if ( isNavigationRequest ) {
            // we want to provide a response body to indicate that we blocked it via an ad blocker
            await zombie.send("Fetch.fulfillRequest", {
                requestId,
                responseHeaders: BLOCKED_HEADERS,
                responseCode: BLOCKED_CODE,
                body: BLOCKED_BODY
              },
              sessionId
            );
          } else {
            await zombie.send("Fetch.failRequest", {
                requestId,
                errorReason: "BlockedByClient"
              },
              sessionId
            );
          }
          blocked = true;
          break;
        } catch(e) {
          console.warn("Issue with intercepting request", e);
        }
      }
    }
    if ( blocked ) return;
    try {
      await zombie.send("Fetch.continueRequest", {
          requestId,
        },
        sessionId
      );
    } catch(e) {
      console.warn("Issue with continuing request", e);
    }
  }
};