Add support for fetch_visitor_authentication event in runtime package (…

…#369)

* Add support for fetch_visitor_authentication event

* Update comment

.changeset/blue-brooms-cough.md

@@ -0,0 +1,5 @@
+---
+'@gitbook/runtime': minor
+---
+
+Add support for fetch_visitor_authentication event

packages/runtime/src/events.ts

@@ -1,4 +1,9 @@
-import { Event, FetchEvent, FetchPublishedScriptEvent } from '@gitbook/api';
+import {
+    Event,
+    FetchEvent,
+    FetchPublishedScriptEvent,
+    FetchVisitorAuthenticationEvent,
+} from '@gitbook/api';
 
 import { RuntimeCallback, RuntimeContext } from './context';
 
@@ -25,7 +30,7 @@ export type EventCallback<
  */
 export type NonFetchEvent = Exclude<
     EventType,
-    FetchEvent['type'] | FetchPublishedScriptEvent['type']
+    FetchEvent['type'] | FetchPublishedScriptEvent['type'] | FetchVisitorAuthenticationEvent['type']
 >;
 
 /**
@@ -53,3 +58,10 @@ export type FetchPublishScriptEventCallback<Context extends RuntimeContext = Run
         Response | undefined | Promise<Response | undefined>, // Scripts can return undefined, in which case a no-op script will be sent back to the caller.
         Context
     >;
+
+/**
+ * Callback to handle visitor authentication fetch event.
+ */
+export type FetchVisitorAuthenticationEventCallback<
+    Context extends RuntimeContext = RuntimeContext
+> = RuntimeCallback<[FetchVisitorAuthenticationEvent], Response | Promise<Response>, Context>;

packages/runtime/src/integrations.ts

@@ -2,7 +2,12 @@ import { Event, IntegrationEnvironment } from '@gitbook/api';
 
 import { ComponentDefinition } from './components';
 import { createContext, RuntimeContext } from './context';
-import { EventCallbackMap, FetchEventCallback, FetchPublishScriptEventCallback } from './events';
+import {
+    EventCallbackMap,
+    FetchEventCallback,
+    FetchPublishScriptEventCallback,
+    FetchVisitorAuthenticationEventCallback,
+} from './events';
 import { Logger } from './logger';
 
 const logger = Logger('integrations');
@@ -19,6 +24,11 @@ interface IntegrationRuntimeDefinition<Context extends RuntimeContext = RuntimeC
      */
     fetch_published_script?: FetchPublishScriptEventCallback<Context>;
 
+    /**
+     * Handler for fetching the visitor auth for an integration.
+     */
+    fetch_visitor_authentication?: FetchVisitorAuthenticationEventCallback<Context>;
+
     /**
      * Handler for GitBook events.
      */
@@ -108,6 +118,21 @@ export function createIntegration<Context extends RuntimeContext = RuntimeContex
                 return resp;
             }
 
+            if (
+                event.type === 'fetch_visitor_authentication' &&
+                definition.fetch_visitor_authentication
+            ) {
+                const resp = await definition.fetch_visitor_authentication(event, context);
+
+                logger.debug(
+                    `response ${resp.status} ${resp.statusText} Content-Type: ${resp.headers.get(
+                        'content-type'
+                    )}`
+                );
+
+                return resp;
+            }
+
             if (event.type === 'ui_render') {
                 const component = components.find((c) => c.componentId === event.componentId);