python - 爬虫将数据更新到数组，在循环内yield

Question

我想使用循环连续抓取和更新数组值，因为我需要单击某个按钮来获取数组上的下一个值。然而，循环内的yield似乎作为并行线程工作，并且该项目多次yield。我想要的是遍历循环，更新数据并仅生成一次项目。例子:当前输出:

{'field1': 'data1',
 'filed2' : 'data2',
 'field3' : ['data31']}

{'field1': 'data1',
 'filed2' : 'data2',
 'field3' : ['data32']}

{'field1': 'data1',
 'filed2' : 'data2',
 'field3' : ['data33']}

预期:

{'field1': 'data1',
 'filed2' : 'data2',
 'field3' : ['data31', 'data32', 'data3']}

这是我的代码

def parse_individual_listings(self, response):
     ...
     data = {}
     data[field1] = 'data1'
     data[field1] = 'data2'
     ...
     for i in range(3):
         yield scrapy.Request(
                urlparse.urljoin(response.url, link['href']), #different link
                callback=self.parse_individual_tabs,
                meta={'data': data, 'n':i};
         )
def parse_individual_tabs(self, response):
     data = response.meta['data']
     i = response.meta['i']
     ...
     # keep populating `data`
     data[field3][i] = "data3[i]"  #this value change when I click a button to update
     yield data

Answer 1

尝试使用inline_requests库(https://pypi.org/project/scrapy-inline-requests/)。它允许您在同一函数内发出请求。将数据收集到一个对象而不是产生不同的数据是很有用的。使用一些伪代码检查此示例:

from inline_requests import inline_requests
from scrapy import Selector

@inline_requests
def parse_individual_listings(self, response):
    ...
    data = {}
    data[field1] = 'data1'
    data[field1] = 'data2'
     ...
    for i in range(3):
        extra_req = yield scrapy.Request(
            response.urljoin(link['href']), #different link
        )
        # apply your logics here, say extract some data
        sel = Selector(text=extra_req.text)
        data['field3'].append(sel.css('some css selector').get())
    yield data