srapy crawl mulitlayer在列表中附加数据并生成此项

Question

我试图使用scrapy解析的网站结构如下：

我希望提取的数据具有以下格式：

[{
    "project":{"projectname":"project1"},
    "samples":["sample1's_content","sample2's_content","sample3's_content"]
 },
 {
    "project":{"projectname":"project2"},
    "samples":["sample1's_content","samples2's_content","sample3's_content"]
}]

我试过了：

from item import Item

class Spider(scrapy.scrapy):
    name = spider

    def start_request(self):
        url = "the main page's url"
        yield scrapy.Request(url=url, callback=self.parseProjectList)

    def parseProjectList(self, response):
        for url in Selector(Project_list)
            yield scrapy.Request(url=url, callback=self.parseProject)

    def parseProject(self, response):
        #scrap some data
        myItem = Item()
        myItem['samples']=[]
        myItem['project']={'projectname':projectname,...}
        yield scrapy.Request(url=SampleListPage, callback=self.parseSampleListPage,meta={'myItem':myItem})

    def parseSampleListPage(self, response):
        for url in Selector(Sample_list)
            yield scrapy.Request(url=url, callback=self.parseSample,meta={'myItem':'myItem'})

    def parseSample(self, response):
        #parse some sample data
        response.meta['myItem'].append(sample_data)

我尝试将yield response.meta['myItem']放在parseSampleListPage

def parseSampleListPage(self, response):
        for url in Selector(Sample_list)
            yield scrapy.Request(url=url, callback=self.parseSample,meta={'myItem':'myItem'})
    yield response.meta['myItem']

以及parseSample

中的yield response.meta['myItem']

def parseSample(self, response):
    #parse some sample data
    response.meta['myItem'].append(sample_data)
    yield response.meta['myItem']

两种解决方案都失败了。

第一个产生空的“样本”字段。第二个创建具有相同项目的多个数据，如下所示：

[   {
    "project": {
      "projectname": "project2"
    },
    "samples": [
      "sample1's_content"
    ]   },   {
    "project": {
      "projectname": "project2"
    },
    "samples": [
      "sample1's_content",
      "sample2's_content"
    ]   },   {
    "project": {
      "projectname": "project2"
    },
    "samples": [
  "sample1's_content",
  "sample2's_content",
  "sample3's_content"
]   } ]

奇怪有没有办法解决这个问题？