def board_check(form, field):
"""
检查板块是否存在，是否可以允许当前用户创建文章或写入
"""
try:
board_id = to_bin(field.data)
except TypeError:
raise ValidationError('板块ID无效')
board = Board.get_by_id(board_id)
if not board:
raise ValidationError('板块不存在')
can_post_rank = 100 if set(form.view.roles) & {'forum_master', 'superuser', 'admin'} else 0
if can_post_rank >= board.can_post_rank:
return True
raise ValidationError('没有权限选择此板块')
