一文搞懂Scrapy与MongoDB交互过程

class MongoDBPipeline:
    def __init__(self,conn,database):
        self.conn = conn
        self.database = database
    @classmethod
    def from_crawler(cls, crawler):
        return cls(
            conn=crawler.settings.get('MONGODB_CONNECTION_STRING'),
            database=crawler.settings.get('MONGODB_DATABASE')
        )
    def open_spider(self,spider):
        # 创建连接对象
        self.client = pymongo.MongoClient(self.conn)
        # 连接要用的使用的数据库
        self.db = self.client[self.database]
    def process_item(self,item,spider):
        # 设置使用表名称
        name = item.__class__.__name__
        # 默认item类名
        self.db[name].insert_one(dict(item))
        return item
    def close_spider(self,spider):
        self.client.close()

db[name].insert_one({'my': 'document'})
db[name].insert_many([{'doc': 2}, {'doc': 3}])

MONGODB_CONNECTION_STRING = '127.0.0.1'
MONGODB_DATABASE = 'test'

class Man:
    id = 0 # 类变量
    def __init__(self, name):
        self.name = name
        self.id = self.id_number()
    @classmethod
    def id_number(cls):
        cls.id += 1
        return cls.id
a = Man('A')
print(a.id)
b = Man('B')
print(b.id)