[Django]-Check if the file format is different with the file name extension in Python, Javascript?

If you would like to do this via Javascript, you can get the mime type of the selected file and do the check in the frontend. The advantage of this is that you won’t need to upload the file to server for initial validations. Based on this, the mime type for .mov files is ‘video/quicktime‘. This is much difficult for a user to modify than changing the file extension.

Also take note of Mathias’ answer. It is important to validate the uploaded file in the backend server as well. 🙂

Here is a demo of file validation using Javascript.

$('#movieFile').change(function() {
    var file = $('#movieFile')[0].files[0];

    var filename = file.name;
    var fileMimeType = file.type;
    var fileExtension = filename.split('.').pop();

    if (isValidMimeType(fileMimeType)) {
        console.log('good file');
    } else {
        console.log('bad file');
    }
});

function isValidMimeType(fileMimeType) {
    // mime type of .mov files
    var validFileMimeTypes = [ 'video/quicktime' ];

    for (var i = 0; i < validFileMimeTypes.length; i++) {
        if (validFileMimeTypes[i].toLowerCase() === fileMimeType.toLowerCase()) {
            return true;
        }
    }
    return false;
}

adding to Mathias’ answer using python-magic you could do this instead

file_type = magic.from_buffer(upload.file.read(1024), mime=True)

this would not require saving the file to get it’s mime