带有附加参数的 mysql 的 start_requests

Question

我正在尝试使用以下方案抓取网站：

我有一个 mysql 表，其中包含有关电影名称及其发行年份的信息。 Scrapy spider 在 start_requests 函数中获取这两个值，然后处理请求。 search_in_filmweb 函数分析响应并检查，结果包含与我从数据库中获得的发布年份相同的发布年份。

假设我的数据库中有如下值：

movie_name：威尼斯之死；发布年份：1971

蜘蛛发送请求为：http://www.filmweb.pl/search?q=Death+in+Venice，然后在发布日期前选择正确的结果。

我编写的蜘蛛可以正常工作，但仅适用于数据库中的一条特定记录（作为 BaseSpider）。但是，当我尝试通过从数据库中获取所有行来发出批量请求时，出现错误：

2014-03-07 18:01:19+0100 [single] DEBUG: Crawled (200) <GET http://www.filmweb.pl/search?q=Death+in+Venice> (referer: None)
2014-03-07 18:01:19+0100 [single] ERROR: Spider error processing <GET http://www.filmweb.pl/search?q=Death+in+Venice>
    Traceback (most recent call last):
      File "/Library/Python/2.7/site-packages/twisted/internet/base.py", line 824, in runUntilCurrent
        call.func(*call.args, **call.kw)
      File "/Library/Python/2.7/site-packages/twisted/internet/task.py", line 638, in _tick
        taskObj._oneWorkUnit()
      File "/Library/Python/2.7/site-packages/twisted/internet/task.py", line 484, in _oneWorkUnit
        result = next(self._iterator)
      File "/Library/Python/2.7/site-packages/scrapy/utils/defer.py", line 57, in <genexpr>
        work = (callable(elem, *args, **named) for elem in iterable)
    --- <exception caught here> ---
      File "/Library/Python/2.7/site-packages/scrapy/utils/defer.py", line 96, in iter_errback
        yield next(it)
      File "/Library/Python/2.7/site-packages/scrapy/contrib/spidermiddleware/offsite.py", line 23, in process_spider_output
        for x in result:
      File "/Library/Python/2.7/site-packages/scrapy/contrib/spidermiddleware/referer.py", line 22, in <genexpr>
        return (_set_referer(r) for r in result or ())
      File "/Library/Python/2.7/site-packages/scrapy/contrib/spidermiddleware/urllength.py", line 33, in <genexpr>
        return (r for r in result or () if _filter(r))
      File "/Library/Python/2.7/site-packages/scrapy/contrib/spidermiddleware/depth.py", line 50, in <genexpr>
        return (r for r in result or () if _filter(r))
      File "/Users/mikolajroszkowski/Desktop/python/scrapy_projects/filmweb_moviecus/filmweb_moviecus/spiders/single.py", line 37, in search_in_filmweb
        yield Request("http://www.filmweb.pl"+item['link_from_search'][0], meta={'item': item}, callback=self.parse)
    exceptions.IndexError: list index out of range

还有蜘蛛代码：

from scrapy.spider import Spider
from scrapy.selector import Selector
from filmweb_moviecus.items import FilmwebItem
from scrapy.http import Request

import MySQLdb
import urllib

class MySpider(Spider):
    name = 'single'
    allowed_domains = ['filmweb.pl']

    def start_requests(self):
        item = FilmwebItem()
        conn = MySQLdb.connect(unix_socket = '/Applications/MAMP/tmp/mysql/mysql.sock', user='root', passwd='root', db='filmypodobne', host='localhost', charset="utf8", use_unicode=True)
        cursor = conn.cursor()
        cursor.execute("SELECT * FROM filmy_app_movies")
        rows = cursor.fetchall()
        for row in rows:
            item['movie_name'] = urllib.quote_plus(row[1])
            item['id_db'] = row[0]
            item['db_year'] = row[3]
            #print row[1]
            #print self.db_year

            yield Request("http://www.filmweb.pl/search?q="+item['movie_name'], meta={'item': item}, callback=self.search_in_filmweb)

    def search_in_filmweb(self, response):
        sel = Selector(response)
        item = response.request.meta['item']
        item['link_from_search'] = sel.xpath('//a[following-sibling::span[contains(.,"%s")]]/@href'%item['db_year']).extract()

        yield Request("http://www.filmweb.pl"+item['link_from_search'][0], meta={'item': item}, callback=self.parse)

    def parse(self, response):
        sel = Selector(response)
        item = response.request.meta['item']

        item['tytul_pl'] = sel.xpath('//div[@class="filmTitle"]/div/h1/a/@title').extract()
        item['tytul_obcy'] = sel.xpath('//div[@class="filmTitle"]/h2/text()').extract()
        item['czas_trwania'] = sel.xpath('//div[@class="filmTime"]/text()').extract()

        yield Request("http://www.filmweb.pl"+item['link_from_search'][0]+'/descs', meta={'item': item}, callback=self.parse_opis)

    def parse_opis(self, response):
        sel = Selector(response)
        item = response.request.meta['item']
        item['opis'] = sel.xpath('//div[@class="pageBox"]//p[@class="text"][1]/text()').extract()

        return item

Answer 1

愚蠢的错误，应该是：

def start_requests(self):
    conn = MySQLdb.connect(unix_socket = '/Applications/MAMP/tmp/mysql/mysql.sock', user='root', passwd='root', db='filmypodobne', host='localhost', charset="utf8", use_unicode=True)
    cursor = conn.cursor()
    cursor.execute("SELECT * FROM filmy_app_movies")
    rows = cursor.fetchall()
    for row in rows:
        item = FilmwebItem()
        item['movie_name'] = urllib.quote_plus(row[1])
        item['id_db'] = row[0]
        item['db_year'] = row[3]
        yield Request("http://www.filmweb.pl/search?q="+item['movie_name'], meta={'item': item}, callback=self.search_in_filmweb)