def public():
    """Allow public access.

    - anyone can read anything
    - authenticated users can comment, tag and compare
    - only admins may delete datasets
    """
    return {'collection': ['__unauthenticated__', '__authenticated__'],
        'comment': ['__authenticated__'], 'compare': ['__authenticated__'],
        'delete': ['admin'], 'detail': ['__unauthenticated__',
        '__authenticated__'], 'file_list': ['__unauthenticated__',
        '__authenticated__'], 'get_partial_url': ['__unauthenticated__',
        '__authenticated__'], 'get_stream_url': ['__unauthenticated__',
        '__authenticated__'], 'rpcs': ['__authenticated__'], 'stream': [
        '__unauthenticated__'], 'tag': ['__authenticated__']}
