Get rid of blocking behaviour, unify Chrome and Firefox processors, u…

…pdate readme

README.md

@@ -73,7 +73,7 @@ If you want to import bangs from DuckDuckGo, see [this page](./ddg/README.md).
 
 ## How the extension works
 
-CBS uses the `WebRequestBlocking` API to intercept requests to the supported search engines, and if a bang is found, redirects the user to the chosen URL with the query inserted.
+CBS uses the `webRequest.onBeforeRequest` event listener to listen for requests to the supported search engines, and if a bang is found, sends the user to the chosen URL with the query inserted, using the `tabs.update` API.
 
 ## Development
 

manifest.firefox.json

@@ -1,7 +1,5 @@
 {
-  "permissions": [
-    "webRequestBlocking"
-  ],
+  "permissions": [],
   "host_permissions": [],
   "background": {
     "scripts": [

src/background/main.ts

@@ -3,8 +3,7 @@ import browser from 'webextension-polyfill';
 import {
   dev, currentBrowser, version, hash, hostPermissions,
 } from '../lib/esbuilddefinitions';
-import chromeProcessRequest from './chrome';
-import firefoxProcessRequest from './firefox';
+import processRequest from './requests';
 import { Settings } from '../lib/settings';
 import * as legacy from './legacy';
 import * as storage from '../lib/storage';
@@ -67,23 +66,15 @@ function main(): void {
     }
   });
 
-  if (currentBrowser === 'chrome') {
-    browser.webRequest.onBeforeRequest.addListener(
-      (r) => {
-        // Type defs don't like an async non-blocking handler.
-        chromeProcessRequest(r);
-      },
-      { urls: hostPermissions },
-      // The requestBody spec is required for handling POST situations.
-      ['requestBody'],
-    );
-  } else {
-    browser.webRequest.onBeforeRequest.addListener(
-      firefoxProcessRequest,
-      { urls: hostPermissions },
-      ['requestBody', 'blocking'],
-    );
-  }
+  browser.webRequest.onBeforeRequest.addListener(
+    (r) => {
+      // Type defs don't like an async non-blocking handler.
+      processRequest(r);
+    },
+    { urls: hostPermissions },
+    // The requestBody opt is required for handling POST situations.
+    ['requestBody'],
+  );
 }
 
 main();

src/background/shared.ts → src/background/requests.ts

@@ -1,10 +1,12 @@
-import { WebRequest } from 'webextension-polyfill';
+import browser, { WebRequest } from 'webextension-polyfill';
 
 import { getBangsLookup } from './lookup';
+import { getIgnoredDomains } from './ignoreddomains';
 
 const possibleQueryParams = ['q', 'query', 'eingabe'];
 
-export function shouldReject(blacklist: Readonly<string[]>, url: string): boolean {
+// Should this URL be rejected provided the given blacklist?
+function shouldReject(blacklist: Readonly<string[]>, url: string): boolean {
   if (blacklist.includes(new URL(url).hostname)) {
     return true;
   }
@@ -25,7 +27,7 @@ function constructRedirect(redirectUrl: string, queryText: string): string {
  * @param request (Optional) The request details object from a WebRequestBlocking event.
  * @returns A list of redirections to issue.
  */
-export async function getRedirects(
+async function getRedirects(
   reqUrl: string,
   request: WebRequest.OnBeforeRequestDetailsType | undefined = undefined,
 ): Promise<string[]> {
@@ -84,3 +86,32 @@ export async function getRedirects(
 
   return Promise.resolve(redirects);
 }
+
+export default async function processRequest(
+  r: WebRequest.OnBeforeRequestDetailsType,
+): Promise<void> {
+  if (r.type !== 'main_frame') {
+    return Promise.resolve();
+  }
+
+  if (shouldReject(await getIgnoredDomains(), r.url)) {
+    return Promise.resolve();
+  }
+
+  // From the current URL, get the redirections (if any) to apply.
+  const redirections = await getRedirects(r.url, r);
+
+  if (redirections.length === 0) {
+    return Promise.resolve();
+  }
+
+  // Open all URLs (except the first) in new tabs
+  for (let i = 1; i < redirections.length; i += 1) {
+    browser.tabs.create({ url: redirections[i] });
+  }
+
+  // Finally send the current tab to the first in the array.
+  browser.tabs.update(r.tabId, { url: redirections[0] });
+
+  return Promise.resolve();
+}