'GuideSpider' 对象不可切片。

我有一个Scrapy项目，想要用它来爬取一些网站。

当我尝试将所有信息保存到MySQL数据库中时，出现了标题中的错误。

我到处都看了，发现这是一个“列表”问题，可能与items[]列表有关...

请帮助我理解这个错误的含义，并告诉我在哪里修复代码。

也请解释一下原因，因为我想要理解。非常感谢。

爬虫代码：

from scrapy.contrib.linkextractors.sgml import SgmlLinkExtractor
from scrapy.contrib.spiders.crawl import Rule, CrawlSpider
from scrapy.selector import HtmlXPathSelector
from gscrape.items import GscrapeItem
class GuideSpider(CrawlSpider):
    name = "Dplay"
    allowed_domains = ['www.example.com']
    start_urls = [
        "http://www.examplea.com/forums/forumdisplay.php?f=108&order=desc&page=1"
    ]
    rules = (
        Rule(SgmlLinkExtractor(allow=("forumdisplay.php.*f=108.*page=")), callback='parse_item', follow=True),
    )
    
    def parse_item(self, response):
        hxs = HtmlXPathSelector(response)
        items = []
        sites = hxs.select('//div')
        for site in sites:
            item = GscrapeItem()
            item['title'] = site.select('a[@class="threadcolor"]/text()').extract()
            item['guide_url'] = site.select('a[@class="threadcolor"]/@href').extract()
            item['subject'] = site.select('./text()[1]').extract()
            items.append(item)
        return items

管道代码：

from scrapy.exceptions import DropItem
from string import join
from scrapy import log
from twisted.enterprise import adbapi
import MySQLdb.cursors
class GscrapePipeline(object):
    def process_item(self, item, spider):
        if item['guide_url']:
            item['guide_url'] = "http://www.example.com/forums/" + join(item['guide_url'])
            return item
        else:
            raise DropItem()
class MySQLStorePipeline(object):
    def __init__(self):
        # @@@ hardcoded db settings
        # TODO: make settings configurable through settings
        self.dbpool = adbapi.ConnectionPool('MySQLdb',
            db='prova',
            host='127.0.0.1',
            user='root',
            passwd='',
            cursorclass=MySQLdb.cursors.DictCursor,
            charset='utf8',
            use_unicode=True
        )
        
    def process_item(self, item, spider):
        # 在线程池中运行数据库查询
        query = self.dbpool.runInteraction(self._conditional_insert, item)
        query.addErrback(self.handle_error)
        return item
    
    def _conditional_insert(self, tx, item):
        # 如果记录不存在，则创建记录
        # 该块在自己的线程上运行
        tx.execute("select * from prova where guide_url = %s", item['guide_url'])
        result = tx.fetchone()
        if result:
            log.msg("Item already stored in db: %s" % item, level=log.DEBUG)
        else:
            tx.execute(
                "insert into prova (title, guide_url, subject) "
                "values (%s, %s, %s)",
                (item['title'],
                 item['guide_url'],
                 item['subject']
                )
            )
            log.msg("Item stored in db: %s" % item, level=log.DEBUG)
            
    def handle_error(self, e):
        log.err(e)

错误：exceptions.TypeError: 'GuideSpider' object is not subscriptable (line 47) pipelines.py