FEATURE: addBeforeAuthCompleteCallback plugin API method

app/assets/javascripts/discourse/app/instance-initializers/auth-complete.js

@@ -15,6 +15,16 @@ const AuthErrors = [
   "not_allowed_from_ip_address",
 ];
 
+const beforeAuthCompleteCallbacks = [];
+
+export function addBeforeAuthCompleteCallback(fn) {
+  beforeAuthCompleteCallbacks.push(fn);
+}
+
+export function resetBeforeAuthCompleteCallbacks() {
+  beforeAuthCompleteCallbacks.length = 0;
+}
+
 export default {
   after: "inject-objects",
   initialize(owner) {
@@ -30,12 +40,17 @@ export default {
       const router = owner.lookup("router:main");
       router.one("didTransition", () => {
         next(() => {
+          const options = JSON.parse(lastAuthResult);
+
+          if (!beforeAuthCompleteCallbacks.every((fn) => fn(options))) {
+            return;
+          }
+
           if (router.currentPath === "invites.show") {
             owner
               .lookup("controller:invites-show")
-              .authenticationComplete(JSON.parse(lastAuthResult));
+              .authenticationComplete(options);
           } else {
-            const options = JSON.parse(lastAuthResult);
             const modal = owner.lookup("service:modal");
             const siteSettings = owner.lookup("service:site-settings");
 

app/assets/javascripts/discourse/app/lib/plugin-api.js

@@ -128,12 +128,13 @@ import { registerCustomUserNavMessagesDropdownRow } from "discourse/controllers/
 import { registerFullPageSearchType } from "discourse/controllers/full-page-search";
 import { registerHashtagType } from "discourse/lib/hashtag-autocomplete";
 import { _addBulkButton } from "discourse/components/modal/topic-bulk-actions";
+import { addBeforeAuthCompleteCallback } from "discourse/instance-initializers/auth-complete";
 
 // If you add any methods to the API ensure you bump up the version number
 // based on Semantic Versioning 2.0.0. Please update the changelog at
 // docs/CHANGELOG-JAVASCRIPT-PLUGIN-API.md whenever you change the version
 // using the format described at https://keepachangelog.com/en/1.0.0/.
-export const PLUGIN_API_VERSION = "1.10.0";
+export const PLUGIN_API_VERSION = "1.11.0";
 
 // This helper prevents us from applying the same `modifyClass` over and over in test mode.
 function canModify(klass, type, resolverName, changes) {
@@ -2400,6 +2401,15 @@ class PluginApi {
     registerFullPageSearchType(translationKey, searchTypeId, searchFunc);
   }
 
+  /**
+   * @param {function} fn - Function that will be called before the auth complete logic is run
+   * in instance-initializers/auth-complete.js. If any single callback returns false, the
+   * auth-complete logic will be aborted.
+   */
+  addBeforeAuthCompleteCallback(fn) {
+    addBeforeAuthCompleteCallback(fn);
+  }
+
   /**
    * Registers a hashtag type and its corresponding class.
    * This is used when generating CSS classes in the hashtag-css-generator.

app/assets/javascripts/discourse/tests/acceptance/auth-complete-test.js

@@ -1,6 +1,7 @@
 import { acceptance, exists } from "discourse/tests/helpers/qunit-helpers";
 import { currentRouteName, visit } from "@ember/test-helpers";
 import { test } from "qunit";
+import { withPluginApi } from "discourse/lib/plugin-api";
 
 acceptance("Auth Complete", function (needs) {
   needs.hooks.beforeEach(() => {
@@ -49,4 +50,28 @@ acceptance("Auth Complete", function (needs) {
       "it shows the registration modal"
     );
   });
+
+  test("Callback added using addBeforeAuthCompleteCallback", async function (assert) {
+    withPluginApi("1.11.0", (api) => {
+      api.addBeforeAuthCompleteCallback(() => {
+        api.container
+          .lookup("router:main")
+          .transitionTo("discovery.categories");
+        return false;
+      });
+    });
+
+    await visit("/");
+
+    assert.strictEqual(
+      currentRouteName(),
+      "discovery.categories",
+      "The function added via API was run and it transitioned to 'discovery.categories' route"
+    );
+
+    assert.notOk(
+      exists("#discourse-modal div.create-account-body"),
+      "registration modal is not shown"
+    );
+  });
 });

app/assets/javascripts/discourse/tests/helpers/qunit-helpers.js

@@ -91,6 +91,7 @@ import { resetMentions } from "discourse/lib/link-mentions";
 import { resetModelTransformers } from "discourse/lib/model-transformers";
 import { cleanupTemporaryModuleRegistrations } from "./temporary-module-helper";
 import { clearBulkButtons } from "discourse/components/modal/topic-bulk-actions";
+import { resetBeforeAuthCompleteCallbacks } from "discourse/instance-initializers/auth-complete";
 
 export function currentUser() {
   return User.create(sessionFixtures["/session/current.json"].current_user);
@@ -228,6 +229,7 @@ export function testCleanup(container, app) {
   cleanupTemporaryModuleRegistrations();
   cleanupCssGeneratorTags();
   clearBulkButtons();
+  resetBeforeAuthCompleteCallbacks();
 }
 
 function cleanupCssGeneratorTags() {

docs/CHANGELOG-JAVASCRIPT-PLUGIN-API.md

@@ -7,6 +7,14 @@ in this file.
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
+## [1.11.0] - 2023-08-30
+
+### Added
+
+- Adds `addBeforeAuthCompleteCallback` which allows plugins and themes to add functions to be 
+  evaluated before the auth-complete logic is run. If any of these callbacks return false, the 
+  auth-complete logic will be aborted.
+
 ## [1.10.0] - 2023-08-25
 
 ### Added