news.py

class NewsPage(Page):
    # Other fields
    writer = models.CharField(max_length=255, blank=True, default=get_current_user_full_name)
    
    content_panels = Page.content_panels + [
        FieldPanel('writer'),
    ]

# ===================
# Utility Functions
# ===================
def get_current_user_full_name():
    request = get_current_request()
    if request:
        return request.user.full_name
    else:
        return ''
      
# get_current_request is our wrapper function around CrequestMiddleware https://pypi.org/project/django-crequest/