使用 meta 的 Scrapy 传递值从未更新

Question

我试图抓取一些网站。我已经获得了数据，并尝试使用 meta={} 传递值。但是当我使用 yield scrapy.Request 进入下一个函数时，问题就出现了。我被发送到下一个函数是一个新的 URL 并使用 meta 传递 JSON 值。我得到了新的 URL 但没有 JSON 数据，JSON 从未更新过。刚刚传递了相同的值。我不知道是怎么回事。

你可以看到我的代码，我试图传递 JSON 值，但我只得到相同的 JSON 但 URL 已更新为新的 [=23] =].

def first_function(self, response):
    value_json = self.get_json() #i got the json from here
    for key, value in value_json.items(): #loop the json
        for values in value:

            # values will show me as dictionay of dictionary
            # thats like {"blabla":{"key1":"value1","key1":"value2"}}
            # I gave the conditions as below to get just a value or to make sure if that key ("blabla") is exist
            # if the condition is true, i will get the value {"key1":"value1","key1":"value2"}

            if values == "blabla":
                get_url = "http://www.example.com/"
                yield Request(
                    url=get_url+values["id_url"],
                    meta={"data_rest":values}, 
                    callback=self.second_function
                )

def second_function(self, response):
    # ============== PROBLEM =====================
    # The problem is here!
    # I always got a new url from first_function, my logic is if I got a new url, i should get a new json
    # but the json or "data_rest" never updated. Always send the same json to this function
    # ============== PROBLEM =====================

    josn_data = response.meta["data_rest"]
    names = response.css() #get the tag in here
    for get_data in names:
        sub_url = get_data.css("a::attr(href)").extract()
        for loop_url_menu in sub_url:
            yield scrapy.Request(
                url=loop_url_menu, 
                headers=self.session,
                meta = {
                    'dont_redirect': True,
                    'handle_httpstatus_list': [302]
                }, callback=self.next_function
            )

Answer 1

好消息！！我可以解决它。我们只需要在我们产生值之后附加第一个值。

def first_function(self, response):
    temp = []
    value_json = self.get_json() #i got the json from here
    for key, value in value_json.items(): #loop the json
        for values in value:
            if values == "blabla":
                get_url = "http://www.example.com/"
                temp.append(values)

    yield Request(
        url=get_url+values["id_url"],
        meta={"data_rest":temp}, 
        callback=self.second_function
    )

使用 meta 的 Scrapy 传递值从未更新

Scrapy pass value using meta never updated

python

scrapy

web-scraping

scrape

python-requests