1 files changed, 13 insertions, 0 deletions

diff --git a/server/helpers/custom-validators/video-captions.ts b/server/helpers/custom-validators/video-captions.ts
index 528edf60c..4cc7dcaf4 100644
--- a/server/helpers/custom-validators/video-captions.ts
+++ b/server/helpers/custom-validators/video-captions.ts
@@ -1,3 +1,5 @@
+import { getFileSize } from '@shared/extra-utils'
+import { readFile } from 'fs-extra'
 import { CONSTRAINTS_FIELDS, MIMETYPES, VIDEO_LANGUAGES } from '../../initializers/constants'
 import { exists, isFileValid } from './misc'
 
@@ -13,9 +15,20 @@ function isVideoCaptionFile (files: { [ fieldname: string ]: Express.Multer.File
   return isFileValid(files, videoCaptionTypesRegex, field, CONSTRAINTS_FIELDS.VIDEO_CAPTIONS.CAPTION_FILE.FILE_SIZE.max)
 }
 
+async function isVTTFileValid (filePath: string) {
+  const size = await getFileSize(filePath)
+
+  if (size > CONSTRAINTS_FIELDS.VIDEO_CAPTIONS.CAPTION_FILE.FILE_SIZE.max) return false
+
+  const content = await readFile(filePath, 'utf8')
+
+  return content?.startsWith('WEBVTT\n')
+}
+
 // ---------------------------------------------------------------------------
 
 export {
   isVideoCaptionFile,
+  isVTTFileValid,
   isVideoCaptionLanguageValid
 }