为什么scrapy在尝试爬取和解析站点时会抛出错误？

Question

下面的代码

class SiteSpider(BaseSpider):
    name = "some_site.com"
    allowed_domains = ["some_site.com"]
    start_urls = [
        "some_site.com/something/another/PRODUCT-CATEGORY1_10652_-1__85667",
    ]
    rules = (
        Rule(SgmlLinkExtractor(allow=('some_site.com/something/another/PRODUCT-CATEGORY_(.*)', ))),

        # Extract links matching 'item.php' and parse them with the spider's method parse_item
        Rule(SgmlLinkExtractor(allow=('some_site.com/something/another/PRODUCT-DETAIL(.*)', )), callback="parse_item"),
    )
    def parse_item(self, response):
.... parse stuff

抛出以下错误

Traceback (most recent call last):
  File "/usr/lib/python2.6/dist-packages/twisted/internet/base.py", line 1174, in mainLoop
    self.runUntilCurrent()
  File "/usr/lib/python2.6/dist-packages/twisted/internet/base.py", line 796, in runUntilCurrent
    call.func(*call.args, **call.kw)
  File "/usr/lib/python2.6/dist-packages/twisted/internet/defer.py", line 318, in callback
    self._startRunCallbacks(result)
  File "/usr/lib/python2.6/dist-packages/twisted/internet/defer.py", line 424, in _startRunCallbacks
    self._runCallbacks()
--- <exception caught here> ---
  File "/usr/lib/python2.6/dist-packages/twisted/internet/defer.py", line 441, in _runCallbacks
    self.result = callback(self.result, *args, **kw)
  File "/usr/lib/pymodules/python2.6/scrapy/spider.py", line 62, in parse
    raise NotImplementedError
exceptions.NotImplementedError: 

当我将回调更改为"parse“，并将函数更改为"parse”时，我没有得到任何错误，但也没有被擦除。我把它改成了"parse_items“，我想我可能会重写parse method by accident。也许我设置的链接提取器是错误的？

我想要做的是解析分类页面上的每个项目链接。我这样做是完全错误的吗？

Answer 1

我需要将BaseSpider更改为CrawlSpider。感谢srapy用户！

http://groups.google.com/group/scrapy-users/browse_thread/thread/4adaba51f7bcd0af#

你好，

，

如果您从BaseSpider更改为CrawlSpider，可能会起作用？BaseSpider似乎没有实现规则，请参阅：

http://doc.scrapy.org/topics/spiders.html?highlight=rule#scrapy.contr...

-M

Answer 2

默认情况下，scrapy会在类中搜索解析函数。在您的爬行器中，缺少解析函数。您提供的不是解析，而是parse_item。如果将parse_item替换为parse，这个问题将得到解决。或者，您可以用parse_item的解析方法覆盖spider.py中的解析方法。