Documentation example fails with `proxy URL with no authority`

Running the example from the documentation yields this:

10:11 $ scrapy runspider quotes.py 
2018-07-11 10:12:04 [scrapy.utils.log] INFO: Scrapy 1.5.0 started (bot: scrapybot)
2018-07-11 10:12:04 [scrapy.utils.log] INFO: Versions: lxml 3.5.0.0, libxml2 2.9.3, cssselect 0.9.1, parsel 1.5.0, w3lib 1.19.0, Twisted 16.0.0, Python 2.7.12 (default, Dec  4 2017, 14:50:18) - [GCC 5.4.0 20160609], pyOpenSSL 0.15.1 (OpenSSL 1.0.2g  1 Mar 2016), cryptography 1.2.3, Platform Linux-4.4.0-130-generic-x86_64-with-Ubuntu-16.04-xenial
2018-07-11 10:12:04 [scrapy.crawler] INFO: Overridden settings: {'SPIDER_LOADER_WARN_ONLY': True}
2018-07-11 10:12:04 [scrapy.middleware] INFO: Enabled extensions:
['scrapy.extensions.memusage.MemoryUsage',
 'scrapy.extensions.logstats.LogStats',
 'scrapy.extensions.telnet.TelnetConsole',
 'scrapy.extensions.corestats.CoreStats']
Unhandled error in Deferred:
2018-07-11 10:12:04 [twisted] CRITICAL: Unhandled error in Deferred:


Traceback (most recent call last):
  File "/usr/local/lib/python2.7/dist-packages/scrapy/commands/runspider.py", line 88, in run
    self.crawler_process.crawl(spidercls, **opts.spargs)
  File "/usr/local/lib/python2.7/dist-packages/scrapy/crawler.py", line 171, in crawl
    return self._crawl(crawler, *args, **kwargs)
  File "/usr/local/lib/python2.7/dist-packages/scrapy/crawler.py", line 175, in _crawl
    d = crawler.crawl(*args, **kwargs)
  File "/usr/lib/python2.7/dist-packages/twisted/internet/defer.py", line 1274, in unwindGenerator
    return _inlineCallbacks(None, gen, Deferred())
--- <exception caught here> ---
  File "/usr/lib/python2.7/dist-packages/twisted/internet/defer.py", line 1128, in _inlineCallbacks
    result = g.send(result)
  File "/usr/local/lib/python2.7/dist-packages/scrapy/crawler.py", line 98, in crawl
    six.reraise(*exc_info)
  File "/usr/local/lib/python2.7/dist-packages/scrapy/crawler.py", line 80, in crawl
    self.engine = self._create_engine()
  File "/usr/local/lib/python2.7/dist-packages/scrapy/crawler.py", line 105, in _create_engine
    return ExecutionEngine(self, lambda _: self.stop())
  File "/usr/local/lib/python2.7/dist-packages/scrapy/core/engine.py", line 69, in __init__
    self.downloader = downloader_cls(crawler)
  File "/usr/local/lib/python2.7/dist-packages/scrapy/core/downloader/__init__.py", line 88, in __init__
    self.middleware = DownloaderMiddlewareManager.from_crawler(crawler)
  File "/usr/local/lib/python2.7/dist-packages/scrapy/middleware.py", line 58, in from_crawler
    return cls.from_settings(crawler.settings, crawler)
  File "/usr/local/lib/python2.7/dist-packages/scrapy/middleware.py", line 36, in from_settings
    mw = mwcls.from_crawler(crawler)
  File "/usr/local/lib/python2.7/dist-packages/scrapy/downloadermiddlewares/httpproxy.py", line 29, in from_crawler
    return cls(auth_encoding)
  File "/usr/local/lib/python2.7/dist-packages/scrapy/downloadermiddlewares/httpproxy.py", line 22, in __init__
    self.proxies[type] = self._get_proxy(url, type)
  File "/usr/local/lib/python2.7/dist-packages/scrapy/downloadermiddlewares/httpproxy.py", line 39, in _get_proxy
    proxy_type, user, password, hostport = _parse_proxy(url)
  File "/usr/lib/python2.7/urllib2.py", line 721, in _parse_proxy
    raise ValueError("proxy URL with no authority: %r" % proxy)
exceptions.ValueError: proxy URL with no authority: '/var/run/docker.sock'
2018-07-11 10:12:04 [twisted] CRITICAL:

Looks like proxy code does not handle no_proxy correctly.

[a-palchikov]

I guess NO_PROXY handling is very open to specific interpretations and is not standardized. Docker client describes the uses of NO_PROXY for its purposes here while scrapy can just ignore the proxy that the urllib2.parse_proxy fails to parse.

[drs-11]

I’m not sure what could be a solution to this issue. /var/run/docker.sock seems the only exception for having a socket file in a no_proxy env variable. So either the socket file be ignored and not added to the list of proxies or maybe add it without passing the socket file path to _get_proxy method which is causing the error?

But the second option will cause further errors when the proxy is parsed in other modules. So I think ignoring the socket file will be the best option? Also I can’t find any other cases where a socket file is used in no_proxy. Thoughts?