Add NoneFileUploader class to handle disabled file uploads

apps/app/src/interfaces/file-uploader.ts

@@ -13,6 +13,7 @@ export type FileUploadType =
 // file upload type strings you can specify in the env variable
 export const FileUploadTypeForEnvVar = {
   ...FileUploadType,
+  none: 'none',
   mongo: 'mongo',
   mongodb: 'mongodb',
   gcp: 'gcp',

apps/app/src/server/service/file-uploader/none.ts

@@ -0,0 +1,129 @@
+import type { Response } from 'express';
+import type { Readable } from 'stream';
+
+import type { ICheckLimitResult } from '~/interfaces/attachment';
+import type Crowi from '~/server/crowi';
+import type { RespondOptions } from '~/server/interfaces/attachment';
+import type { IAttachmentDocument } from '~/server/models/attachment';
+
+import {
+  AbstractFileUploader,
+  type SaveFileParam,
+  type TemporaryUrl,
+} from './file-uploader';
+
+/**
+ * NoneFileUploader is a placeholder uploader when file upload is disabled.
+ * All write operations are disabled, but read operations return empty results.
+ */
+class NoneFileUploader extends AbstractFileUploader {
+  /**
+   * @inheritdoc
+   */
+  override getIsUploadable(): boolean {
+    return false;
+  }
+
+  /**
+   * @inheritdoc
+   */
+  override isValidUploadSettings(): boolean {
+    return false;
+  }
+
+  /**
+   * @inheritdoc
+   */
+  override async isWritable(): Promise<boolean> {
+    return false;
+  }
+
+  /**
+   * @inheritdoc
+   */
+  override getIsReadable(): boolean {
+    return false;
+  }
+
+  /**
+   * @inheritdoc
+   */
+  override listFiles(): [] {
+    return [];
+  }
+
+  /**
+   * @inheritdoc
+   */
+  override saveFile(_param: SaveFileParam): Promise<void> {
+    throw new Error('File upload is disabled');
+  }
+
+  /**
+   * @inheritdoc
+   */
+  override deleteFile(_attachment: IAttachmentDocument): void {
+    throw new Error('File upload is disabled');
+  }
+
+  /**
+   * @inheritdoc
+   */
+  override deleteFiles(_attachments: IAttachmentDocument[]): void {
+    throw new Error('File upload is disabled');
+  }
+
+  /**
+   * @inheritdoc
+   */
+  override checkLimit(_uploadFileSize: number): Promise<ICheckLimitResult> {
+    return Promise.resolve({
+      isUploadable: false,
+      errorMessage: 'File upload is disabled',
+    });
+  }
+
+  /**
+   * @inheritdoc
+   */
+  override async uploadAttachment(
+    _readable: Readable,
+    _attachment: IAttachmentDocument,
+  ): Promise<void> {
+    throw new Error('File upload is disabled');
+  }
+
+  /**
+   * @inheritdoc
+   */
+  override respond(
+    res: Response,
+    _attachment: IAttachmentDocument,
+    _opts?: RespondOptions,
+  ): void {
+    res.status(404).send('File upload is disabled');
+  }
+
+  /**
+   * @inheritdoc
+   */
+  override findDeliveryFile(
+    _attachment: IAttachmentDocument,
+  ): Promise<NodeJS.ReadableStream> {
+    throw new Error('File upload is disabled');
+  }
+
+  /**
+   * @inheritdoc
+   */
+  override generateTemporaryUrl(
+    _attachment: IAttachmentDocument,
+    _opts?: RespondOptions,
+  ): Promise<TemporaryUrl> {
+    throw new Error('File upload is disabled');
+  }
+}
+
+module.exports = (crowi: Crowi) => {
+  return new NoneFileUploader(crowi);
+};