引发 ValueError('请求 url 中缺少方案：%s' % self._url) ValueError：请求 url 中缺少方案：javascript:void(0);

Question

这是我的蜘蛛代码

蜘蛛.py

import scrapy

class ExampleSpider(scrapy.Spider):
    name = 'moneycontrol'
    # allowed_domains = ['moneycontrol.com']
    start_urls = ['https://www.moneycontrol.com/india/stockpricequote/']

    def parse(self, response):
        stoke_link_list = response.css("table a::attr(href)").getall()

        if response.css("span.span_price_wrap::text").getall(): # value of this variable only present in first run
            stock_name =  response.css("h1.pcstname::text").get()
            bse_price, nse_price = response.css("span.span_price_wrap::text").getall()
            print(stock_name + ' ' + bse_price + ' ' + nse_price)
        else:
            print('stock_name bse_price nse_price')

        for link in stoke_link_list:
            if link is not None:
                next_page = response.urljoin(link)
                # yield scrapy.Request(next_page, callback=self.parse)
                yield response.follow(next_page, callback=self.parse)

在运行此程序时，我遇到了一个奇怪的错误。在再次运行时抓取某些网站时会出错

错误：

2020-08-20 19:52:49 [scrapy.core.scraper] ERROR: Spider error processing <GET https://www.moneycontrol.com/mutual-funds/nav/motilal-oswal-midcap-30-fund-regular-plan/MMO025> (referer: https://www.moneycontrol.com/india/stockpricequote/pharmaceuticals/abbottindia/AI51)
Traceback (most recent call last):


  File "/home/vishvajeet/Desktop/Programming/python/scrapy/env/lib/python3.6/site-packages/scrapy/utils/defer.py", line 120, in iter_errback
    yield next(it)
  File "/home/vishvajeet/Desktop/Programming/python/scrapy/env/lib/python3.6/site-packages/scrapy/utils/python.py", line 346, in __next__
    return next(self.data)
  File "/home/vishvajeet/Desktop/Programming/python/scrapy/env/lib/python3.6/site-packages/scrapy/utils/python.py", line 346, in __next__
    return next(self.data)
  File "/home/vishvajeet/Desktop/Programming/python/scrapy/env/lib/python3.6/site-packages/scrapy/core/spidermw.py", line 64, in _evaluate_iterable
    for r in iterable:
  File "/home/vishvajeet/Desktop/Programming/python/scrapy/env/lib/python3.6/site-packages/scrapy/spidermiddlewares/offsite.py", line 29, in process_spider_output
    for x in result:
  File "/home/vishvajeet/Desktop/Programming/python/scrapy/env/lib/python3.6/site-packages/scrapy/core/spidermw.py", line 64, in _evaluate_iterable
    for r in iterable:
  File "/home/vishvajeet/Desktop/Programming/python/scrapy/env/lib/python3.6/site-packages/scrapy/spidermiddlewares/referer.py", line 340, in <genexpr>
    return (_set_referer(r) for r in result or ())
  File "/home/vishvajeet/Desktop/Programming/python/scrapy/env/lib/python3.6/site-packages/scrapy/core/spidermw.py", line 64, in _evaluate_iterable
    for r in iterable:
  File "/home/vishvajeet/Desktop/Programming/python/scrapy/env/lib/python3.6/site-packages/scrapy/spidermiddlewares/urllength.py", line 37, in <genexpr>
    return (r for r in result or () if _filter(r))
  File "/home/vishvajeet/Desktop/Programming/python/scrapy/env/lib/python3.6/site-packages/scrapy/core/spidermw.py", line 64, in _evaluate_iterable
    for r in iterable:
  File "/home/vishvajeet/Desktop/Programming/python/scrapy/env/lib/python3.6/site-packages/scrapy/spidermiddlewares/depth.py", line 58, in <genexpr>
    return (r for r in result or () if _filter(r))
  File "/home/vishvajeet/Desktop/Programming/python/scrapy/env/lib/python3.6/site-packages/scrapy/core/spidermw.py", line 64, in _evaluate_iterable
    for r in iterable:
  File "/home/vishvajeet/Desktop/Programming/python/scrapy/moneycontrol/moneycontrol/spiders/my_spider.py", line 24, in parse
    yield scrapy.Request(next_page, callback=self.parse)
  File "/home/vishvajeet/Desktop/Programming/python/scrapy/env/lib/python3.6/site-packages/scrapy/http/request/__init__.py", line 25, in __init__
    self._set_url(url)
  File "/home/vishvajeet/Desktop/Programming/python/scrapy/env/lib/python3.6/site-packages/scrapy/http/request/__init__.py", line 69, in _set_url
    raise ValueError('Missing scheme in request url: %s' % self._url)
ValueError: Missing scheme in request url: javascript:void(0);

运行2

2020-08-20 19:55:15 [scrapy.core.scraper] ERROR: Spider error processing <GET https://www.moneycontrol.com/mutual-funds/nav/dsp-equity-opportunities-fund-regular-plan/MDS011> (referer: https://www.moneycontrol.com/india/stockpricequote/pharmaceuticals/alkemlaboratories/AL05)
Traceback (most recent call last):
  File "/home/vishvajeet/Desktop/Programming/python/scrapy/env/lib/python3.6/site-packages/scrapy/utils/defer.py", line 120, in iter_errback
    yield next(it)
  File "/home/vishvajeet/Desktop/Programming/python/scrapy/env/lib/python3.6/site-packages/scrapy/utils/python.py", line 346, in __next__
    return next(self.data)
  File "/home/vishvajeet/Desktop/Programming/python/scrapy/env/lib/python3.6/site-packages/scrapy/utils/python.py", line 346, in __next__
    return next(self.data)
  File "/home/vishvajeet/Desktop/Programming/python/scrapy/env/lib/python3.6/site-packages/scrapy/core/spidermw.py", line 64, in _evaluate_iterable
    for r in iterable:
  File "/home/vishvajeet/Desktop/Programming/python/scrapy/env/lib/python3.6/site-packages/scrapy/spidermiddlewares/offsite.py", line 29, in process_spider_output
    for x in result:
  File "/home/vishvajeet/Desktop/Programming/python/scrapy/env/lib/python3.6/site-packages/scrapy/core/spidermw.py", line 64, in _evaluate_iterable
    for r in iterable:
  File "/home/vishvajeet/Desktop/Programming/python/scrapy/env/lib/python3.6/site-packages/scrapy/spidermiddlewares/referer.py", line 340, in <genexpr>
    return (_set_referer(r) for r in result or ())
  File "/home/vishvajeet/Desktop/Programming/python/scrapy/env/lib/python3.6/site-packages/scrapy/core/spidermw.py", line 64, in _evaluate_iterable
    for r in iterable:
  File "/home/vishvajeet/Desktop/Programming/python/scrapy/env/lib/python3.6/site-packages/scrapy/spidermiddlewares/urllength.py", line 37, in <genexpr>
    return (r for r in result or () if _filter(r))
  File "/home/vishvajeet/Desktop/Programming/python/scrapy/env/lib/python3.6/site-packages/scrapy/core/spidermw.py", line 64, in _evaluate_iterable
    for r in iterable:
  File "/home/vishvajeet/Desktop/Programming/python/scrapy/env/lib/python3.6/site-packages/scrapy/spidermiddlewares/depth.py", line 58, in <genexpr>
    return (r for r in result or () if _filter(r))
  File "/home/vishvajeet/Desktop/Programming/python/scrapy/env/lib/python3.6/site-packages/scrapy/core/spidermw.py", line 64, in _evaluate_iterable
    for r in iterable:
  File "/home/vishvajeet/Desktop/Programming/python/scrapy/moneycontrol/moneycontrol/spiders/my_spider.py", line 24, in parse
    yield scrapy.Request(next_page, callback=self.parse)
  File "/home/vishvajeet/Desktop/Programming/python/scrapy/env/lib/python3.6/site-packages/scrapy/http/request/__init__.py", line 25, in __init__
    self._set_url(url)
  File "/home/vishvajeet/Desktop/Programming/python/scrapy/env/lib/python3.6/site-packages/scrapy/http/request/__init__.py", line 69, in _set_url
    raise ValueError('Missing scheme in request url: %s' % self._url)
ValueError: Missing scheme in request url: javascript:void(0);

我查看了其他 stackoverflow 答案，但没有一个能解决我的问题。喜欢尝试start_urls 列出，使用关注等。 Missing scheme in request URL

Answer 1

错误“Missing scheme in request url”表示该 URL 没有 http:// 或 https:// 前缀。

问题是由于正在测试的网页中存在具有相对 URL 的链接而发生的。

例如，moneycontrol.com 网站上名为“Zee entertainment”的链接具有

“/india/stockpricequote/mediaentertainment/zeeentertainmententerprises/ZEE”的href值

因此，当 Python 程序尝试打开此链接时，会抛出“缺少方案”错误。

---

如何解决问题？

'missing scheme'的问题可以通过前置来解决 https://hostname 到所有相对 URL 链接（即不以 http:// 或 https:// 开头的链接）

代码 sn-p 将 https://hostname 添加到相对 URL：

for link in stoke_link_list:
    if link is not None:
        if not link.startswith("https://moneycontrol.com/")
            page_url = ("https://moneycontrol.com/" + link)