上載到數據庫時，scrapy引發錯誤

Question

我得到的錯誤消息是：exceptions.TypeError：'NoneType'對象沒有屬性' getitem '。 這是我的代碼：

# -*- coding: utf-8 -*-
import scrapy,MySQLdb,codecs
from scrapy import Request

class MyItems(scrapy.Item):
    topLinks = scrapy.Field() #links at top of home page to grab artist page
    artists = scrapy.Field() # list of all the artists
    artists_urls = scrapy.Field() #url of the page for the artist + songs
    song_name = scrapy.Field() #name of each song
    song_duration = scrapy.Field() #duration of the song, duh
    song_dl = scrapy.Field() #dl link for the proxy site for songs
    rd = scrapy.Field()


class UpdaterSpider(scrapy.Spider):
    name = "updater"
    allowed_domains = [
        'myfreemp3.cc', 'unref.eu', 'safeurl.eu'
    ]
    start_urls = (
        'http://www.example.com/',
    )

    def __init__(self, *a, **kw):
        super(UpdaterSpider, self).__init__(*a, **kw)

        self.item = MyItems()
        self.db = MySQLdb.connect( #setup my SQL database info
            "127.0.0.1", #host
            "root", #user
            "uconn3", #password
            "Music" #database
        )

        self.cursor = self.db.cursor() #create a cursor to execute SQL statements

        self.item = MyItems()
        self.y = 0

    def parse(self, response):
        sql = "SELECT * FROM Songs"

        self.cursor.execute(sql)

        result = self.cursor.fetchone()

        while result is not None:
            yield Request(url=result[3], callback= lambda r: self.parse_dl(r, result[1], result[2]))

            result = self.cursor.fetchone()

    def parse_dl(self, response, songname, duration):
        self.item['rd'] = response.xpath("//head/script/text()").extract()

        for x in range(len(self.item['rd'])):
            self.item['rd'][x] = self.item['rd'][x].split('"')[1]


            sql = "INSERT INTO Songs (" \
                "Artist, songName, Duration, URL, Genre) " \
                "VALUES ('Placeholder', '%s', '%s', '%s', 'Placeholder')" % \
                (songname.decode('utf-8'), duration.decode('utf-8'), self.item['rd'][x])

            self.cursor.execute(sql)

            self.db.commit()

當我刪除sql語句行時，該錯誤已修復，但我無法弄清楚為什么這會弄亂事情。

edit1：追溯

Traceback (most recent call last):
      File "/usr/lib/python2.7/dist-packages/twisted/internet/base.py", line 1201, in mainLoop
        self.runUntilCurrent()
      File "/usr/lib/python2.7/dist-packages/twisted/internet/base.py", line 824, in runUntilCurrent
        call.func(*call.args, **call.kw)
      File "/usr/lib/python2.7/dist-packages/twisted/internet/defer.py", line 382, in callback
        self._startRunCallbacks(result)
      File "/usr/lib/python2.7/dist-packages/twisted/internet/defer.py", line 490, in _startRunCallbacks
        self._runCallbacks()
    --- <exception caught here> ---
      File "/usr/lib/python2.7/dist-packages/twisted/internet/defer.py", line 577, in _runCallbacks
        current.result = callback(current.result, *args, **kw)
      File "/home/user/PycharmProjects/untitled/mp3_scraper/mp3_scraper/spiders/updater.py", line 48, in <lambda>
        yield Request(url=result[3], callback= lambda r: self.parse_dl(r, result[1], result[2]))
    exceptions.TypeError: 'NoneType' object has no attribute '__getitem__'

Answer 1

看起來像

  self.item = MyItems()

沒有方法大括號[]調用的方法getitem我認為-問題不在數據庫中，請提供完整的追溯