蜘蛛 returns 仅 items.json 文件中的“[”

Question

我编写了蜘蛛程序来从网站中提取图像。但是 items.json 文件中只有 [ 字符。请帮我。我的蜘蛛文件是这样的：-

    # -*- coding: utf-8 -*-

from scrapy.contrib.spiders import CrawlSpider, Rule
from scrapy.selector import HtmlXPathSelector
from captcha.items import CaptchaItem

class CaptchaSpider(CrawlSpider):
    name = "CaptchaSpider"
    allowed_domains = ["*****.ac.in"]
    start_urls = [
      "https://*****.ac.in/*****.asp"
    ]

def parse_item(self, response):
    item = CaptchaItem()
    hxs = HtmlXPathSelector(response)
    item['im'] = hxs.select('//img/@src').extract()
    return item

我的 items.py 文件是这样的：-

import scrapy


class CaptchaItem(scrapy.Item):
    # define the fields for your item here like:
    # name = scrapy.Field()
    im = scrapy.Field()
    pass

Answer 1

如果抓取时出现错误或没有返回任何项目，输出文件将仅包含 [。

你的情况是因为缩进，parse_item()应该缩进：

class CaptchaSpider(CrawlSpider):
    name = "CaptchaSpider"
    allowed_domains = ["*****.ac.in"]
    start_urls = [
      "https://*****.ac.in/*****.asp"
    ]

    def parse_item(self, response):
        item = CaptchaItem()
        hxs = HtmlXPathSelector(response)
        item['im'] = hxs.select('//img/@src').extract()
        return item

我已经实际测试并复制了它：

$ scrapy runspider spider.py -o items.json
...
$ cat items.json
[

蜘蛛 returns 仅 items.json 文件中的“[”

Spider returns only "[" in the items.json file

python

json

scrapy

web-scraping

scrapy-spider