feat: preview config (#21561)

* feat: base files for static preview

* feat: preview config

* Update packages/core/content-manager/server/src/preview/routes/index.ts

Co-authored-by: Rémi de Juvigny <8087692+remidej@users.noreply.github.com>

* chore: empty handler

* chore: comment controllers type

* fix: remove is enabled check from load

* feat: test preview config

* chore: refactor type

* fix: pr comments

---------

Co-authored-by: Rémi de Juvigny <8087692+remidej@users.noreply.github.com>

examples/getstarted/config/admin.js

@@ -18,4 +18,12 @@ module.exports = ({ env }) => ({
     nps: env.bool('FLAG_NPS', true),
     promoteEE: env.bool('FLAG_PROMOTE_EE', true),
   },
+  preview: {
+    enabled: env.bool('PREVIEW_ENABLED', true),
+    config: {
+      handler: (uid, { documentId, locale, status }) => {
+        return `/preview/${uid}/${documentId}/${locale}/${status}`;
+      },
+    },
+  },
 });

packages/core/content-manager/server/src/preview/index.ts

@@ -4,6 +4,7 @@ import { FEATURE_ID } from './constants';
 import { routes } from './routes';
 import { controllers } from './controllers';
 import { services } from './services';
+import { getService } from './utils';
 
 /**
  * Check once if the feature is enabled before loading it,
@@ -24,11 +25,8 @@ const getFeature = (): Partial<Plugin.LoadedPlugin> => {
       // eslint-disable-next-line no-console -- TODO remove when we have real functionality
       console.log('Bootstrapping preview server');
 
-      // eslint-disable-next-line @typescript-eslint/no-unused-vars -- TODO: Remove when implemented
-      const config = strapi.config.get('admin.preview');
-
-      // TODO: Validation
-      // TODO: Disable feature if config is not valid
+      const config = getService(strapi, 'preview-config');
+      config.validate();
     },
     routes,
     controllers,

packages/core/content-manager/server/src/preview/services/__tests__/preview-config.test.ts

@@ -0,0 +1,55 @@
+import { createPreviewConfigService } from '../preview-config';
+
+const getConfig = (enabled: boolean, handler: () => void) => {
+  return {
+    enabled,
+    config: {
+      handler,
+    },
+  };
+};
+
+describe('Preview Config', () => {
+  test('Is not enabled by default', () => {
+    const strapi = {
+      config: {
+        get: () => undefined,
+      },
+    } as any;
+
+    expect(createPreviewConfigService({ strapi }).isEnabled()).toBe(false);
+  });
+
+  test('Is enabled when configuration is set', () => {
+    const strapi = {
+      config: {
+        get: () => getConfig(true, () => {}),
+      },
+    } as any;
+
+    expect(createPreviewConfigService({ strapi }).isEnabled()).toBe(true);
+  });
+
+  describe('Validation', () => {
+    test('Passes on valid configuration', () => {
+      const strapi = {
+        config: {
+          get: () => getConfig(true, () => {}),
+        },
+      } as any;
+
+      createPreviewConfigService({ strapi }).validate();
+    });
+
+    test('Fails on missing handler', () => {
+      const strapi = {
+        config: {
+          // @ts-expect-error - invalid handler
+          get: () => getConfig(true, 3),
+        },
+      } as any;
+
+      expect(() => createPreviewConfigService({ strapi }).validate()).toThrowError();
+    });
+  });
+});

packages/core/content-manager/server/src/preview/services/index.ts

@@ -1,6 +1,9 @@
 import type { Plugin } from '@strapi/types';
+
 import { createPreviewService } from './preview';
+import { createPreviewConfigService } from './preview-config';
 
 export const services = {
   preview: createPreviewService,
+  'preview-config': createPreviewConfigService,
 } satisfies Plugin.LoadedPlugin['services'];

packages/core/content-manager/server/src/preview/services/preview-config.ts

@@ -0,0 +1,69 @@
+import type { Core, UID } from '@strapi/types';
+import { errors } from '@strapi/utils';
+
+export type HandlerParams = {
+  documentId: string;
+  locale: string;
+  status: 'published' | 'draft';
+};
+
+export interface PreviewConfig {
+  enabled: boolean;
+  config: {
+    handler: (uid: UID.Schema, params: HandlerParams) => string | undefined;
+  };
+}
+
+/**
+ * Read configuration for static preview
+ */
+const createPreviewConfigService = ({ strapi }: { strapi: Core.Strapi }) => {
+  return {
+    isEnabled() {
+      const config = strapi.config.get('admin.preview') as PreviewConfig;
+
+      if (!config) {
+        return false;
+      }
+
+      return config?.enabled ?? true;
+    },
+
+    /**
+     * Validate if the configuration is valid
+     */
+    validate() {
+      if (!this.isEnabled()) {
+        return;
+      }
+
+      const handler = this.getPreviewHandler();
+
+      // Handler must be a function
+      if (typeof handler !== 'function') {
+        throw new errors.ValidationError(
+          'Preview configuration is invalid. Handler must be a function'
+        );
+      }
+    },
+
+    /**
+     * Utility to get the preview handler from the configuration
+     */
+    getPreviewHandler(): PreviewConfig['config']['handler'] {
+      const config = strapi.config.get('admin.preview') as PreviewConfig;
+
+      const emptyHandler = () => {
+        return undefined;
+      };
+
+      if (!this.isEnabled()) {
+        return emptyHandler;
+      }
+
+      return config?.config?.handler || emptyHandler;
+    },
+  };
+};
+
+export { createPreviewConfigService };