有没有办法在不同的formdata上循环Scrapy？

# middlewares.py
class FormDataMiddleware(object):
    def process_request(self, request, spider):
        if 'formdata' in request.meta:
            formdata_list = request.meta['formdata']
            for formdata in formdata_list:
                request_copy = request.copy()
                request_copy.meta['formdata'] = formdata
                yield request_copy

# settings.py
DOWNLOADER_MIDDLEWARES = {
    'your_project_name.middlewares.FormDataMiddleware': 543,
}

# your_spider.py
class YourSpider(scrapy.Spider):
    name = 'your_spider'

    def start_requests(self):
        formdata_list = [
            {'key1': 'value1'},
            {'key2': 'value2'},
            # 添加更多的formdata
        ]
        for formdata in formdata_list:
            yield scrapy.Request(url='http://example.com', meta={'formdata': formdata}, callback=self.parse)

    def parse(self, response):
        # 解析响应数据
        pass