引言： Scrapy是爬虫界大名鼎鼎的存在，在Linux下安装非常顺利，但是在Windows下确实非常多的问题发生，这里记录存在的各类问题以及如何解决。

1.   安装Scrapy失败

     直接在windows下安装scrapy大概率会是失败的，各类不同的原因，主要是各类依赖包未必全部安装，故依据具体的问题而定。

     >> pip install scrapy

2.   安装visual c++ build tools

    这个工具是由微软提供，主要是用于编译相关的源代码而成的：

    下载地址： http://www.microsoft.com/zh-CN/download/details.aspx?id=48159

3.  openssl 之不是有效的win 32程序

Traceback (most recent call last):
  File "D:\Program Files\python\Scripts\scrapy-script.py", line 11, in <module>
    load_entry_point('scrapy==1.1.3', 'console_scripts', 'scrapy')()
  File "D:\Program Files\python\lib\site-packages\scrapy-1.1.3-py3.5.egg\scrapy\cmdline.py", line 121, in execute
    cmds = _get_commands_dict(settings, inproject)
  File "D:\Program Files\python\lib\site-packages\scrapy-1.1.3-py3.5.egg\scrapy\cmdline.py", line 45, in _get_commands_dict
    cmds = _get_commands_from_module('scrapy.commands', inproject)
  File "D:\Program Files\python\lib\site-packages\scrapy-1.1.3-py3.5.egg\scrapy\cmdline.py", line 28, in _get_commands_from_module
    for cmd in _iter_command_classes(module):
  File "D:\Program Files\python\lib\site-packages\scrapy-1.1.3-py3.5.egg\scrapy\cmdline.py", line 19, in _iter_command_classes
    for module in walk_modules(module_name):
  File "D:\Program Files\python\lib\site-packages\scrapy-1.1.3-py3.5.egg\scrapy\utils\misc.py", line 71, in walk_modules
    submod = import_module(fullpath)
  File "D:\Program Files\python\lib\importlib\__init__.py", line 126, in import_module
    return _bootstrap._gcd_import(name[level:], package, level)
  File "<frozen importlib._bootstrap>", line 978, in _gcd_import
  File "<frozen importlib._bootstrap>", line 961, in _find_and_load
  File "<frozen importlib._bootstrap>", line 950, in _find_and_load_unlocked
  File "<frozen importlib._bootstrap>", line 655, in _load_unlocked
  File "<frozen importlib._bootstrap_external>", line 678, in exec_module
  File "<frozen importlib._bootstrap>", line 205, in _call_with_frames_removed
  File "D:\Program Files\python\lib\site-packages\scrapy-1.1.3-py3.5.egg\scrapy\commands\version.py", line 6, in <module>
    import OpenSSL
  File "D:\Program Files\python\lib\site-packages\OpenSSL\__init__.py", line 8, in <module>
    from OpenSSL import rand, crypto, SSL
  File "D:\Program Files\python\lib\site-packages\OpenSSL\rand.py", line 12, in <module>
    from OpenSSL._util import (
  File "D:\Program Files\python\lib\site-packages\OpenSSL\_util.py", line 6, in <module>
    from cryptography.hazmat.bindings.openssl.binding import Binding
  File "D:\Program Files\python\lib\site-packages\cryptography\hazmat\bindings\openssl\binding.py", line 14, in <module>
    from cryptography.hazmat.bindings._openssl import ffi, lib
ImportError: DLL load failed: %1 不是有效的 Win32 应用程序。

如何解决？

 >>   pip3 uninstall pyopenssl

 >>  pip3 uninstall cryptography

 >>  pip3 install pyopenssl

  >>  pip3 install cryptography

4.   问题 ModuleNotFoundError: No module named '_cffi_backend'

   错误信息：

2017-03-31 14:56:42 [scrapy] INFO: Scrapy 1.1.3 started (bot: scrapybot)
2017-03-31 14:56:42 [scrapy] INFO: Overridden settings: {'DUPEFILTER_CLASS': 'scrapy.dupefilters.BaseDupeFilter', 'LOGSTATS_INTERVAL': 0}
2017-03-31 14:56:42 [scrapy] INFO: Enabled extensions:
['scrapy.extensions.corestats.CoreStats',
 'scrapy.extensions.telnet.TelnetConsole']
Traceback (most recent call last):
  File "D:\Program Files\python\Scripts\scrapy-script.py", line 11, in <module>
    load_entry_point('scrapy==1.1.3', 'console_scripts', 'scrapy')()
  File "D:\Program Files\python\lib\site-packages\scrapy-1.1.3-py3.5.egg\scrapy\cmdline.py", line 142, in execute
    _run_print_help(parser, _run_command, cmd, args, opts)
  File "D:\Program Files\python\lib\site-packages\scrapy-1.1.3-py3.5.egg\scrapy\cmdline.py", line 88, in _run_print_help
    func(*a, **kw)
  File "D:\Program Files\python\lib\site-packages\scrapy-1.1.3-py3.5.egg\scrapy\cmdline.py", line 149, in _run_command
    cmd.run(args, opts)
  File "D:\Program Files\python\lib\site-packages\scrapy-1.1.3-py3.5.egg\scrapy\commands\shell.py", line 65, in run
    crawler.engine = crawler._create_engine()
  File "D:\Program Files\python\lib\site-packages\scrapy-1.1.3-py3.5.egg\scrapy\crawler.py", line 97, in _create_engine
    return ExecutionEngine(self, lambda _: self.stop())
  File "D:\Program Files\python\lib\site-packages\scrapy-1.1.3-py3.5.egg\scrapy\core\engine.py", line 68, in __init__
    self.downloader = downloader_cls(crawler)
  File "D:\Program Files\python\lib\site-packages\scrapy-1.1.3-py3.5.egg\scrapy\core\downloader\__init__.py", line 88, in __init__
    self.middleware = DownloaderMiddlewareManager.from_crawler(crawler)
  File "D:\Program Files\python\lib\site-packages\scrapy-1.1.3-py3.5.egg\scrapy\middleware.py", line 58, in from_crawler
    return cls.from_settings(crawler.settings, crawler)
  File "D:\Program Files\python\lib\site-packages\scrapy-1.1.3-py3.5.egg\scrapy\middleware.py", line 34, in from_settings
    mwcls = load_object(clspath)
  File "D:\Program Files\python\lib\site-packages\scrapy-1.1.3-py3.5.egg\scrapy\utils\misc.py", line 44, in load_object
    mod = import_module(module)
  File "D:\Program Files\python\lib\importlib\__init__.py", line 126, in import_module
    return _bootstrap._gcd_import(name[level:], package, level)
  File "<frozen importlib._bootstrap>", line 978, in _gcd_import
  File "<frozen importlib._bootstrap>", line 961, in _find_and_load
  File "<frozen importlib._bootstrap>", line 950, in _find_and_load_unlocked
  File "<frozen importlib._bootstrap>", line 655, in _load_unlocked
  File "<frozen importlib._bootstrap_external>", line 678, in exec_module
  File "<frozen importlib._bootstrap>", line 205, in _call_with_frames_removed
  File "D:\Program Files\python\lib\site-packages\scrapy-1.1.3-py3.5.egg\scrapy\downloadermiddlewares\retry.py", line 23, in <module>
    from scrapy.xlib.tx import ResponseFailed
  File "D:\Program Files\python\lib\site-packages\scrapy-1.1.3-py3.5.egg\scrapy\xlib\tx\__init__.py", line 3, in <module>
    from twisted.web import client
  File "D:\Program Files\python\lib\site-packages\twisted\web\client.py", line 42, in <module>
    from twisted.internet.endpoints import HostnameEndpoint, wrapClientTLS
  File "D:\Program Files\python\lib\site-packages\twisted\internet\endpoints.py", line 37, in <module>
    from twisted.internet.stdio import StandardIO, PipeAddress
  File "D:\Program Files\python\lib\site-packages\twisted\internet\stdio.py", line 30, in <module>
    from twisted.internet import _win32stdio
  File "D:\Program Files\python\lib\site-packages\twisted\internet\_win32stdio.py", line 9, in <module>
    import win32api
ModuleNotFoundError: No module named 'win32api'

 How to solve it?

  >> pip install pypiwin32

5.  scrapy shell url 发生TypeError: 'float' object is not iterable

  错误信息： 

2017-03-31 15:07:16 [scrapy] DEBUG: Telnet console listening on 127.0.0.1:6023
2017-03-31 15:07:16 [scrapy] INFO: Spider opened
Traceback (most recent call last):
  File "D:\Program Files\python\Scripts\scrapy-script.py", line 11, in <module>
    load_entry_point('scrapy==1.1.3', 'console_scripts', 'scrapy')()
  File "D:\Program Files\python\lib\site-packages\scrapy-1.1.3-py3.5.egg\scrapy\cmdline.py", line 142, in execute
    _run_print_help(parser, _run_command, cmd, args, opts)
  File "D:\Program Files\python\lib\site-packages\scrapy-1.1.3-py3.5.egg\scrapy\cmdline.py", line 88, in _run_print_hel
    func(*a, **kw)
  File "D:\Program Files\python\lib\site-packages\scrapy-1.1.3-py3.5.egg\scrapy\cmdline.py", line 149, in _run_command
    cmd.run(args, opts)
  File "D:\Program Files\python\lib\site-packages\scrapy-1.1.3-py3.5.egg\scrapy\commands\shell.py", line 71, in run
    shell.start(url=url)
  File "D:\Program Files\python\lib\site-packages\scrapy-1.1.3-py3.5.egg\scrapy\shell.py", line 47, in start
    self.fetch(url, spider)
  File "D:\Program Files\python\lib\site-packages\scrapy-1.1.3-py3.5.egg\scrapy\shell.py", line 112, in fetch
    reactor, self._schedule, request, spider)
  File "D:\Program Files\python\lib\site-packages\twisted\internet\threads.py", line 122, in blockingCallFromThread
    result.raiseException()
  File "D:\Program Files\python\lib\site-packages\twisted\python\failure.py", line 372, in raiseException
    raise self.value.with_traceback(self.tb)
TypeError: 'float' object is not iterable

   检查当下的twisted版本是17.1.0， 需要切换至16.6.0

　>>  pip uninstall twisted

    >> pip install twisted==16.6.0

6.  总结

   scrapy在Linux安装非常顺利，但是在Windows上却问题多多，一波三折，个人建议，如果玩开发，还是推荐linux或者mac。