fix: allow creating folders even if the mime type validation is set (#509)

Author: fenos

src/storage/limits.ts

@@ -115,3 +115,7 @@ export function parseFileSizeToBytes(valueWithUnit: string) {
 export function isUuid(value: string) {
   return /^[0-9a-f]{8}-[0-9a-f]{4}-[0-5][0-9a-f]{3}-[089ab][0-9a-f]{3}-[0-9a-f]{12}$/i.test(value)
 }
+
+export function isEmptyFolder(object: string) {
+  return object.endsWith('.emptyFolderPlaceholder')
+}

src/storage/uploader.ts

@@ -5,7 +5,7 @@ import { ERRORS } from '@internal/errors'
 import { FileUploadedSuccess, FileUploadStarted } from '@internal/monitoring/metrics'
 
 import { ObjectMetadata, StorageBackendAdapter } from './backend'
-import { getFileSizeLimit } from './limits'
+import { getFileSizeLimit, isEmptyFolder } from './limits'
 import { Database } from './database'
 import { ObjectAdminDelete, ObjectCreatedPostEvent, ObjectCreatedPutEvent } from './events'
 import { getConfig } from '../config'
@@ -81,10 +81,15 @@ export class Uploader {
   async upload(request: FastifyRequest, options: UploaderOptions) {
     const version = await this.prepareUpload(options)
 
+    // When is an empty folder we restrict it to 0 bytes
+    if (isEmptyFolder(options.objectName)) {
+      options.fileSizeLimit = 0
+    }
+
     try {
       const file = await this.incomingFileInfo(request, options)
 
-      if (options.allowedMimeTypes) {
+      if (options.allowedMimeTypes && !isEmptyFolder(options.objectName)) {
         this.validateMimeType(file.mimeType, options.allowedMimeTypes)
       }
 

src/test/object.test.ts

@@ -380,6 +380,43 @@ describe('testing POST object via multipart upload', () => {
     expect(S3Backend.prototype.uploadObject).not.toHaveBeenCalled()
   })
 
+  test('can create an empty folder when mime-type is set', async () => {
+    const form = new FormData()
+    const headers = Object.assign({}, form.getHeaders(), {
+      authorization: `Bearer ${serviceKey}`,
+      'x-upsert': 'true',
+    })
+
+    form.append('file', Buffer.alloc(0))
+
+    const response = await app().inject({
+      method: 'POST',
+      url: '/object/public-limit-mime-types/nested/.emptyFolderPlaceholder',
+      headers,
+      payload: form,
+    })
+    expect(response.statusCode).toBe(200)
+    expect(S3Backend.prototype.uploadObject).toHaveBeenCalled()
+  })
+
+  test('cannot create an empty folder with more than 0kb', async () => {
+    const form = new FormData()
+    const headers = Object.assign({}, form.getHeaders(), {
+      authorization: `Bearer ${serviceKey}`,
+      'x-upsert': 'true',
+    })
+
+    form.append('file', Buffer.alloc(1))
+
+    const response = await app().inject({
+      method: 'POST',
+      url: '/object/public-limit-mime-types/nested-2/.emptyFolderPlaceholder',
+      headers,
+      payload: form,
+    })
+    expect(response.statusCode).toBe(400)
+  })
+
   test('return 422 when uploading an object with a malformed mime-type', async () => {
     const form = new FormData()
     form.append('file', fs.createReadStream(`./src/test/assets/sadcat.jpg`))