Grails CommandObject validating when it should fail

Question

I have the following Command Object in my Grails 2.2.3 application.

@Validateable
class PictureCommand {

    MultipartFile picture
    String notes
    Boolean isDocument

    static constraints = {
        picture nullable: false, validator: { val ->
            if (!val.contentType in ['image/jpeg', 'image/png', 'image/pjpeg', 'image/gif','image/bmp'])
                return 'fileType.invalid'
        }
        notes nullable: true
        isDocument nullable: true
    }
}

This allows for uploading a picture file, and ensures that it is in the list of valid types. The problem, however, is I can upload files that are NOT in that list. When I call cmd.validate() I get true, then I call cmd.hasErrors() and get false. I have tried returning the String 'fileType.invalid' and the List ['fileType.invalid'] and neither work. Does anyone have any ideas? Thanks.

Answer 1

You need some parentheses to get the correct operator order:

if (!(val.contentType in ['image/jpeg', 'image/png', 'image/pjpeg', 'image/gif','image/bmp']))

Currently it's evaluating !val first, and that's always true if it's not null or blank.