Function validateMediaFileType

apps/sim/lib/uploads/utils/validation.ts:366–398

(
  fileName: string,
  mimeType: string
)

}

export function validateMediaFileType(
  fileName: string,
  mimeType: string
): FileValidationError | null {
  const raw = extractExtension(fileName)
  const extension = isAlphanumericExtension(raw) ? raw : ''

  const isAudio = SUPPORTED_AUDIO_EXTENSIONS.includes(extension as SupportedAudioExtension)
  const isVideo = SUPPORTED_VIDEO_EXTENSIONS.includes(extension as SupportedVideoExtension)

  if (!isAudio && !isVideo) {
    return {
      code: 'UNSUPPORTED_FILE_TYPE',
      message: `Unsupported media file type${extension ? `: ${extension}` : ` for "${fileName}"`}. Supported audio types: ${SUPPORTED_AUDIO_EXTENSIONS.join(', ')}. Supported video types: ${SUPPORTED_VIDEO_EXTENSIONS.join(', ')}`,
      supportedTypes: [...SUPPORTED_AUDIO_EXTENSIONS, ...SUPPORTED_VIDEO_EXTENSIONS],
    }
  }

  const baseMimeType = mimeType.split(';')[0].trim()
  const allowedMimeTypes = isAudio
    ? SUPPORTED_AUDIO_MIME_TYPES[extension as SupportedAudioExtension]
    : SUPPORTED_VIDEO_MIME_TYPES[extension as SupportedVideoExtension]

  if (!allowedMimeTypes.includes(baseMimeType)) {
    return {
      code: 'MIME_TYPE_MISMATCH',
      message: `MIME type ${baseMimeType} does not match file extension ${extension}. Expected: ${allowedMimeTypes.join(', ')}`,
      supportedTypes: allowedMimeTypes,
    }
  }

  return null
}