为 Scrapy 安装包依赖项

Question

因此，在用户需要为 Scrapy 安装的众多软件包中，我认为我在使用 pyOpenSSL 时遇到了问题。

当我尝试创建一个教程 Scrapy 项目时，我得到以下输出：

Traceback (most recent call last):
  File "C:\Python27\lib\runpy.py", line 162, in _run_module_as_main
    "__main__", fname, loader, pkg_name)
  File "C:\Python27\lib\runpy.py", line 72, in _run_code
    exec code in run_globals
  File "C:\Python27\lib\site-packages\scrapy\cmdline.py", line 168, in <module>
    execute()
  File "C:\Python27\lib\site-packages\scrapy\cmdline.py", line 122, in execute
    cmds = _get_commands_dict(settings, inproject)
  File "C:\Python27\lib\site-packages\scrapy\cmdline.py", line 46, in _get_comma
nds_dict
    cmds = _get_commands_from_module('scrapy.commands', inproject)
  File "C:\Python27\lib\site-packages\scrapy\cmdline.py", line 29, in _get_comma
nds_from_module
    for cmd in _iter_command_classes(module):
  File "C:\Python27\lib\site-packages\scrapy\cmdline.py", line 20, in _iter_comm
and_classes
    for module in walk_modules(module_name):
  File "C:\Python27\lib\site-packages\scrapy\utils\misc.py", line 68, in walk_mo
dules
    submod = import_module(fullpath)
  File "C:\Python27\lib\importlib\__init__.py", line 37, in import_module
    __import__(name)
  File "C:\Python27\lib\site-packages\scrapy\commands\bench.py", line 3, in <mod
ule>
    from scrapy.tests.mockserver import MockServer
  File "C:\Python27\lib\site-packages\scrapy\tests\mockserver.py", line 6, in <m
odule>
    from twisted.internet import reactor, defer, ssl
  File "C:\Python27\lib\site-packages\twisted\internet\ssl.py", line 59, in <mod
ule>
    from OpenSSL import SSL
  File "build\bdist.win32\egg\OpenSSL\__init__.py", line 8, in <module>
  File "build\bdist.win32\egg\OpenSSL\rand.py", line 11, in <module>
  File "build\bdist.win32\egg\OpenSSL\_util.py", line 3, in <module>
ImportError: No module named cryptography.hazmat.bindings.openssl.binding

当我在谷歌上搜索最后一个错误（没有名为 cryptography.hazmat 的模块）时，我看到一些提到 pyOpenSSL。所以我继续尝试运行easy_install pyOpenSSL==0.14 以确保它是最新版本，但是当我这样做时，我得到了以下输出：

c:\python27\include\pymath.h(22) : warning C4273: 'round' : inconsistent dll lin
kage
        C:\Program Files (x86)\Microsoft Visual Studio 12.0\VC\INCLUDE\math.h(51
6) : see previous definition of 'round'
c:\users\bk\appdata\local\temp\easy_install-tztawu\cryptography-0.4\temp\easy_in
stall-svxsjy\cffi-0.8.2\c\misc_win32.h(225) : error C2632: 'char' followed by 'b
ool' is illegal
c:\users\bk\appdata\local\temp\easy_install-tztawu\cryptography-0.4\temp\easy_in
stall-svxsjy\cffi-0.8.2\c\misc_win32.h(225) : warning C4091: 'typedef ' : ignore
d on left of 'unsigned char' when no variable is declared
c/_cffi_backend.c(5295) : warning C4146: unary minus operator applied to unsigne
d type, result still unsigned
c/_cffi_backend.c(5296) : warning C4146: unary minus operator applied to unsigne
d type, result still unsigned
c/_cffi_backend.c(5297) : warning C4146: unary minus operator applied to unsigne
d type, result still unsigned
c/_cffi_backend.c(5298) : warning C4146: unary minus operator applied to unsigne
d type, result still unsigned
error: Setup script exited with error: command '"C:\Program Files (x86)\Microsof
t Visual Studio 12.0\VC\BIN\cl.exe"' failed with exit status 2

所以我有点不知道我需要做什么才能让 Scrapy 正常运行

Answer 1

我强烈建议使用conda 而不是pip，尤其是在使用Windows 时。 在许多其他事情中，它将为您的系统获取适当的二进制文件。它使设置科学的 Python 环境（想想 Scipy、Numpy、Pandas ......）变得轻而易举。

所以，阅读Anaconda，安装Anaconda，然后执行：

conda create -n scrapyenv python=2  # creates a new py2 environment
activate scrapyenv                  # switch to the new environment
conda install scrapy                # install scrapy

仅当您希望将其封装在单独的环境中时，才需要执行步骤一和二。顺便说一句，如果你这样做conda install anaconda，将会安装一整套有用的软件包。

另外，如果conda 不包含pyOpenSSL 或者您不想安装anaconda，请查看教程How to install Scrapy in 64bit Windows 7 的第9 点。

Answer 2

我在 Mac OS 上遇到了同样的错误。

我通过使用 openssl 0.13 而不是最新版本解决了这个问题。

easy_install pyOpenSSL==0.13

或

pip install pyOpenSSL==0.13

Answer 3

我遇到了同样的问题，并尝试用第一个答案解决它，但它不起作用。 最后，我删除了 pyOpenSSL 并下载了 pyopenssl 安装程序。问题就解决了。 pyopenssl 的网址是： https://launchpad.net/pyopenssl

Answer 4

您应该先升级pip，然后再尝试安装Scrapy：

pip install --upgrade pip
pip install Scrapy