Scrapy「The Twisted> = 13.1.0'發行版沒有被發現，Scrapy需要」

Question

我在virtualenv裏安裝了Ubuntu 12.04，python 3.5.2上的scrapy。我在安裝scrapy時遇到了很多麻煩，但我終於安裝了所有要求。我必須手動安裝twis​​ted才能完成安裝，但我已安裝Twisted 17.0。但是，當我嘗試運行教程時，出現以下錯誤：

Traceback (most recent call last): 
File "/usr/local/bin/scrapy", line 5, in <module> 
    from pkg_resources import load_entry_point 
File "/usr/local/lib/python3.5/site-packages/pkg_resources/__init__.py", line 2927, in <module> 
@_call_aside 
File "/usr/local/lib/python3.5/site-packages/pkg_resources/__init__.py", line 2913, in _call_aside 
f(*args, **kwargs) 
File "/usr/local/lib/python3.5/site-packages/pkg_resources/__init__.py", line 2940, in _initialize_master_working_set 
working_set = WorkingSet._build_master() 
File "/usr/local/lib/python3.5/site-packages/pkg_resources/__init__.py", line 635, in _build_master 
ws.require(__requires__) 
File "/usr/local/lib/python3.5/site-packages/pkg_resources/__init__.py", line 943, in require 
needed = self.resolve(parse_requirements(requirements)) 
File "/usr/local/lib/python3.5/site-packages/pkg_resources/__init__.py", line 829, in resolve 
raise DistributionNotFound(req, requirers) 
pkg_resources.DistributionNotFound: The 'Twisted>=13.1.0' distribution was not found and is required by Scrapy 

Twisted 17.0已安裝，似乎正在工作。當我導入scrapy並在Python中扭曲時，我沒有得到任何錯誤（它找到了模塊），但作爲命令，scrapy不起作用。

Python 3.5.2 (default, Nov 2 2016, 11:15:44) 
[GCC 4.6.3] on linux 
Type "help", "copyright", "credits" or "license" for more information. 
>>> import scrapy 
>>> import twisted 

Answer 1

您將需要爲涉及的所有擴展模塊安裝構建依賴項。那將至少包括GCC，libffi-dev的，和中的libssl-dev的（但可能更多）：

sudo apt-get install gcc libffi-dev libssl-dev 

在安裝編譯依賴，你應該安裝的的Python軟件的所有到的virtualenv 。

virtualenv --python=python3.5 scrapy-environment 
. scrapy-environment/bin/activate 
pip install scrapy 
scrapy ... 

如果您遇到一些錯誤，請更新您的問題以包含該錯誤的詳細信息。