Scrapy 错误：“管道”对象没有属性“导出器”

Question

我制作了一个刮刀，并正在使用this 教程使用管道导出。当我运行scrapy crawl [myspider] 时，我看到终端中的对象闪烁，但每次运行后都会出现错误'PostPipeline' object has no attribute 'exporter'。

我的蜘蛛

class FokSpider1(CrawlSpider):
name = 'fok'
allowed_domains = ['fok.nl']
start_urls = ['http://forum.fok.nl/?token=77c1f767bc31859fee1ffe041343fa48&allowcookies=ACCEPTEER+ALLE+COOKIES']

rules = (
    # My rules, leave out to save space
)

def __init__(self, *args, **kwargs):
    self.driver = webdriver.Chrome()
    super(FokSpider1, self).__init__(*args, **kwargs)

def parse_topic(self, response):
    posts = response.xpath("//div[contains(@class, 'post userid')]")

    for i, post in enumerate(posts):
        l = ItemLoader(selector=post, item=ForumTopic(), response=response)
        l.add_xpath('subforum_title',"//*[@id='pageWrapper']/div[4]/div/h2/a/text()")
        l.add_xpath('topic_title',"//*[@id='pageWrapper']/div[4]/h1/span/text()")
        l.add_xpath('unique_post_id', ".//@data-postid")
        l.add_xpath('post_rank', ".//@data-teller")
        l.add_xpath('author', ".//@data-member")
        l.add_xpath('timestamp', ".//span[contains(@class, 'post_time')]/a[1]/text()")
        l.add_xpath('content', ".//div[contains(@id, '_bot')]/div[contains(@class, 'postmain_right')]/text()")
        yield l.load_item()

settings.py

ITEM_PIPELINES = {
   'scrapy_spider.pipelines.PostPipeline': 300,
}

我认为 settings.py 的其余部分不相关？

pipelines.py

from scrapy.exceptions import DropItem
from scrapy import signals
from scrapy.exporters import XmlItemExporter


class PostPipeline(object):
    def __init__(self):
        self.ids_seen = set()
        self.files = {}

    @classmethod
    def from_crawler(cls, crawler):
        pipeline = cls()
        crawler.signals.connect(pipeline.spider_opened, signals.spider_opened)
        crawler.signals.connect(pipeline.spider_closed, signals.spider_closed)
        return pipeline

    def spider_opened(self, spider):
        file = open('fokSpider1.xml' % spider.name, 'w+b')
        self.files[spider] = file
        self.exporter = XmlItemExporter(file)
        self.exporter.start_exporting()

    def spider_closed(self, spider):
        self.exporter.finish_exporting()
        file = self.files.pop(spider)
        file.close()

    def process_item(self, item, spider):
        if item['unique_post_id'] in self.ids_seen:
            raise DropItem("Duplicate item found: %s" % item)
        else:
            self.ids_seen.add(item['unique_post_id'])
            self.exporter.export_item(item)
            return item

其他信息

process_item 方法引发错误：

    2017-12-18 17:24:00 [scrapy.core.scraper] ERROR: Error processing {'author': u'HaverMoutKoekje',
 'content': u'Here is the content',
 'post_rank': u'7',
 'subforum_title': u'televisie',
 'timestamp': u'vrijdag 8 december 2017 @ 21:59',
 'unique_post_id': u'175586521'}
**Traceback (most recent call last):
  File "/anaconda/lib/python2.7/site-packages/twisted/internet/defer.py", line 653, in _runCallbacks
    current.result = callback(current.result, *args, **kw)
  File "/Users/my.name/scrapy/scrapy_spider/scrapy_spider/pipelines.py", line 40, in process_item
    self.exporter.export_item(item)
AttributeError: 'PostPipeline' object has no attribute 'exporter'**

当我运行scrapy crawl [myspider] -o somefile.xml 时，文件已创建，但它没有内容。

与here 相同的错误，但那里没有答案...

非常感谢任何帮助！

更新： 虽然没有真正解决这个问题，但我现在至少可以使用简单的管道导出数据

from scrapy.exceptions import DropItem

class PostPipeline(object):
    def __init__(self):
        self.ids_seen = set()
        self.files = {}

    def process_item(self, item, spider):
        if item['unique_post_id'] in self.ids_seen:
            raise DropItem("Duplicate item found: %s" % item)
        else:
            self.ids_seen.add(item['unique_post_id'])
            return item

使用命令scrapy crawl [myspider] -o somefile.xml。为什么直接从教程中获取的早期方法不起作用，仍然不知道。

Answer 1

file = open('fokSpider1.xml' % spider.name, 'w+b')

这看起来不对。但是为什么它没有引发错误？

无论如何，可能是这个原因，你的exporter参数不正确，所以没有初始化。