如何从数据帧中为scrapy中的每个start_url分配ID

class MySpider(scrapy.Spider):
    name = 'myspider'
    
    def __init__(self, *args, **kwargs):
        super(MySpider, self).__init__(*args, **kwargs)
        self.id_counter = 0

def start_requests(self):
    for index, row in df.iterrows():
        start_url = row['start_url']
        request = scrapy.Request(url=start_url, callback=self.parse)
        request.meta['id'] = self.id_counter  # 将ID存储在request的meta中
        self.id_counter += 1
        yield request

def parse(self, response):
    item = MyItem()
    item['id'] = response.meta['id']
    # 其他处理逻辑...
    yield item