Allow blank answer in a rich-text-editor question

[firasm]

I'd like to allow my students to submit nothing in a pl-rich-text-editor question:

However, students see an 'invalid, not gradeable when they leave it blank. Of course this doesn't have any consequences since the question is worth 0 points, but still I'd like to know how to remove the 'invalid format error.

I suppose a better, more general way, would be to submit a PR with a parameter allow-blank like in other pl-elements, but in the meantime, I know there's a way to do this using server.py but I can't quite get it to work.

I know that a blank submission ("") works out to be (after the encoding business): ZnNkZ2RmZwoK
Replacing a blank submission with N/A works out to be: Ti9BCgo=

I tried this in server.py:

def parse(data):
    
    if data["format_errors"] == {}:
        pass
    else:
        data['submitted_answers']['_files'] = [
            {
                'name': 'anything_else.md',
                'contents': "Ti9BCgo="
            }
        ]

Rather than if data["format_errors"] == {}:, I also tried: if data["submitted_answers"]['_files'][0]['contents'] == 'ZnNkZ2RmZwoK': but I got a KeyError:

KeyError: '_files'
Traceback (most recent call last):

Any ideas? At this point, I know I'm making this too complicated.

[jonatanschroeder]

You are changing the content, but not clearing the error. Try:

def parse(data):
    if '_files' in data['format_errors']:
        del data['format_errors']['_files']

And it's probably a good idea to have an issue for adding allow-blank to pl-rich-text-editor (and maybe pl-file-editor as well).

[firasm]

Thanks! I thought the error would be removed if I removed the offending text, but I think I would have needed to do the replacement at an earlier stage (and I'm not even sure if that's possible).

Here was my final parse(data) function:

def parse(data):
    
    if '_files' in data['format_errors']:
        del data['format_errors']['_files']
        data['submitted_answers']['_files'] = [
            {
                'name': 'anything_else.md',
                'contents': "Ti9BCgo="
            }
        ]

which gives me this if a student leaves the last question blank: