使用Scrapy下载图片的问题

Question

我在尝试使用带有 Scrapy 的蜘蛛下载图像时遇到以下错误。

File "C:\Python27\lib\site-packages\scrapy\http\request\__init__.py",
line 61, in _set_url
            raise ValueError('Missing scheme in request url: %s' % self._url)
        exceptions.ValueError: Missing scheme in request url: h

据我所知，我好像在某处 url 中缺少 "h"？但我一辈子都看不到在哪里。如果我不尝试下载图像，一切正常。但是一旦我将适当的代码添加到下面的四个文件中，我就无法正常工作。谁能帮我理解这个错误？

items.py

import scrapy

class ProductItem(scrapy.Item):
    model = scrapy.Field()
    shortdesc = scrapy.Field()
    desc = scrapy.Field()
    series = scrapy.Field()
    imageorig = scrapy.Field()
    image_urls = scrapy.Field()
    images = scrapy.Field()

settings.py

BOT_NAME = 'allenheath'

SPIDER_MODULES = ['allenheath.spiders']
NEWSPIDER_MODULE = 'allenheath.spiders'

ITEM_PIPELINES = {'scrapy.contrib.pipeline.images.ImagesPipeline': 1}

IMAGES_STORE = 'c:/allenheath/images'

pipelines.py

class AllenheathPipeline(object):
    def process_item(self, item, spider):
        return item

import scrapy
from scrapy.contrib.pipeline.images import ImagesPipeline
from scrapy.exceptions import DropItem

class MyImagesPipeline(ImagesPipeline):

    def get_media_requests(self, item, info):
        for image_url in item['image_urls']:
            yield scrapy.Request(image_url)

    def item_completed(self, results, item, info):
        image_paths = [x['path'] for ok, x in results if ok]
        if not image_paths:
            raise DropItem("Item contains no images")
        item['image_paths'] = image_paths
        return item

products.py（我的蜘蛛）

import scrapy

from allenheath.items import ProductItem
from scrapy.selector import Selector
from scrapy.http import HtmlResponse

class productsSpider(scrapy.Spider):
    name = "products"
    allowed_domains = ["http://www.allen-heath.com/"]
    start_urls = [
        "http://www.allen-heath.com/ahproducts/ilive-80/",
        "http://www.allen-heath.com/ahproducts/ilive-112/"
    ]

    def parse(self, response):
        for sel in response.xpath('/html'):
            item = ProductItem()
            item['model'] = sel.css('#prodsingleouter > div > div > h2::text').extract()
            item['shortdesc'] = sel.css('#prodsingleouter > div > div > h3::text').extract()
            item['desc'] = sel.css('#tab1 #productcontent').extract()
            item['series'] = sel.css('#pagestrip > div > div > a:nth-child(3)::text').extract()
            item['imageorig'] = sel.css('#prodsingleouter > div > div > h2::text').extract()
            item['image_urls'] = sel.css('#tab1 #productcontent img').extract()[0]
            item['image_urls'] = 'http://www.allen-heath.com' + item['image_urls']
            yield item

如有任何帮助，我们将不胜感激。

Answer 1

问题在这里：

def get_media_requests(self, item, info):
    for image_url in item['image_urls']:
        yield scrapy.Request(image_url)

这里：

item['image_urls'] = sel.css('#tab1 #productcontent img').extract()[0]

您正在提取该字段并取第一个元素。这意味着一旦你在管道中迭代它，你实际上是在迭代 URL 中的字符，它以 http 开头 - 解释你看到的错误消息，一旦第一个尝试处理信件：

Missing scheme in request url: h

从行中删除 [0]。当你这样做时，获取图像的 src，而不是整个元素：

item['image_urls'] = sel.css('#tab1 #productcontent img').xpath('./@src').extract()

之后，您还应该更新下一行，以防图像 url 是相对图像，将其转换为绝对图像：

import urlparse  # put this at the top of the script
item['image_urls'] = [urlparse.urljoin(response.url, url) for url in item['image_urls']]

但是如果 src 中的图像 URL 实际上是绝对的，则不需要最后这一部分，因此只需将其删除。

使用Scrapy下载图片的问题

Trouble with downloading images using Scrapy

python

scrapy