image/svg+xml mimetype converting into application/xml

[VarshaJatav]

I am using HasMimeType decorator of 'nestjs-form-data' in dto.
@HasMimeType([
'image/bmp',
'image/gif',
'image/jpeg',
'image/png',
'image/webp',
'image/svg+xml',
])

When uploading the svg file of mime type 'image/svg+xml', I was getting validation error of mimetype.
Error message -> "File must be of one of the types image/bmp, image/gif, image/jpeg, image/png, image/webp, image/svg+xml"

I tried to check the mimetype of image by commenting this decorator, so I found that it was converting the mimetype 'image/svg+xml' to 'application/xml' which violates the validations.

Console message of the file uploaded ->
FileSystemStoredFile {
originalName: 'image.svg',
encoding: '7bit',
busBoyMimeType: 'image/svg+xml',
path: '/home/Documents/project/image.svg',
size: 100314,
fileType: { ext: 'xml', mime: 'application/xml' }
}

This is problematic as we are using the fileType.ext extension to save the file to our database and when this is streamed, the image is unrenderable as the path now refers to a file with extension .xml instead of the correct .svg.

[VarshaJatav]

@dmitriy-nz Please look into this

[MrSatan]

i have the same problem here. my svg file's mime type is application/xml

[maclementED]

The issue appears to be here. The file-type package does not natively detect all XML types and recommends using a third-party processor (reference).

A potential solution is to update this function to use a custom XML detector:

const streamWithFileType = await FileType.stream(stream);
const storedFile = await (this.config['storage'] as any).create({
  originalName,
  encoding,
  mimetype,
}, streamWithFileType, this.config);
storedFile.setFileTypeResult(streamWithFileType.fileType);