python – Mongoengine – 如何执行“保存新项目或增量计数器”

为此,我存储图像src URL和图像遇到的次数.

MongoEngine模型定义如下：

class ImagesUrl(Document):
    """ Model representing images encountered during web-scraping.

    When an image is encountered on a web-page during scraping,we store its url and the number of times it has been
    seen (default counter value is 1).
    If the image had been seen before,we do not insert a new document
    in collection,but merely increment the corresponding counter value.

    """

    # The url of the image. There cannot be any duplicate.
    src = URLField(required=True,unique=True)

    # counter of the total number of occurences of the image during
    # the datamining process
    counter = IntField(min_value=0,required=True,default=1)

我正在寻找实现“保存或增量”过程的正确方法.

到目前为止,我正在以这种方式处理它,但我觉得可能有更好的,内置的方式使用MongoEngine：

def save_or_increment(self):
    """ If it is the first time the image has been encountered,insert
        its src in mongo,along with a counter=1 value.
        If not,increment its counter value by 1.

    """ 
    # check if item is already stored
    # if not,save a new item
    if not ImagesUrl.objects(src=self.src):
        ImagesUrl(
            src=self.src,counter=self.counter,).save()
    else:
        # if item already stored in Mongo,just increment its counter
        ImagesUrl.objects(src=self.src).update_one(inc__counter=1)

有没有更好的方法呢？

非常感谢您的宝贵时间.