OS X Python 3.7 openssl 终极冲突解决大法（PART 2）

本文主要是介绍OS X Python 3.7 openssl 终极冲突解决大法（PART 2），希望对大家解决编程问题提供一定的参考价值，需要的开发者们随着小编来一起学习吧！

OS X Python 3.7 openssl 终极冲突解决大法（PART 2）

前文：OS X Python 3.7 openssl 终极冲突解决大法（PART 1）

继续思考问题

继续昨天的思路，思考一个问题：官网下载的Python3.7安装后能够完美的使用openssl，而Homebrew安装的就不行，肯定是差了一些东西，既然已经安装了openssl，那么有可能是配置文件又问题？或者是系统路径设置问题？或者是缺少一些引用文件？

一步步来找到问题所在，首先，看看Python导入SSL时有什么错误：

$ python3
Python 3.7.2 (default, Feb 12 2019, 08:16:11) 
[Clang 9.0.0 (clang-900.0.39.2)] on darwin
Type "help", "copyright", "credits" or "license" for more information.
>>> import ssl
Traceback (most recent call last):File "<stdin>", line 1, in <module>File "/usr/local/Cellar/python/3.7.2_2/Frameworks/Python.framework/Versions/3.7/lib/python3.7/ssl.py", line 98, in <module>import _ssl             # if we can't import it, let the error propagate
ImportError: dlopen(/usr/local/Cellar/python/3.7.2_2/Frameworks/Python.framework/Versions/3.7/lib/python3.7/lib-dynload/_ssl.cpython-37m-darwin.so, 2): Library not loaded: /usr/local/opt/openssl/lib/libssl.1.0.0.dylibReferenced from: /usr/local/Cellar/python/3.7.2_2/Frameworks/Python.framework/Versions/3.7/lib/python3.7/lib-dynload/_ssl.cpython-37m-darwin.soReason: image not found

能确定的是缺少一些文件导致Python不能正确的使用SSL，那么，这些文件在哪儿？应该在哪儿？现在是否隐藏在那个路径中，是否需要在系统环境变量中添加这些路径？

卸载Homebrew安装的openssl，再重新安装一遍。

$ brew install opensslUpdating Homebrew...
==> Downloading https://homebrew.bintray.com/bottles/openssl-1.0.2q.sierra.bottl
Already downloaded: /Users/tianshuo/Library/Caches/Homebrew/downloads/b6dec2b57ee88a3cb02335284971b3b1e902d8b43fef115b456a971e5d0981ce--openssl-1.0.2q.sierra.bottle.tar.gz
==> Pouring openssl-1.0.2q.sierra.bottle.tar.gz
==> Caveats
A CA file has been bootstrapped using certificates from the SystemRoots
keychain. To add additional certificates (e.g. the certificates added in
the System keychain), place .pem files in/usr/local/etc/openssl/certsand run/usr/local/opt/openssl/bin/c_rehashopenssl is keg-only, which means it was not symlinked into /usr/local,
because Apple has deprecated use of OpenSSL in favor of its own TLS and crypto libraries.If you need to have openssl first in your PATH run:echo 'export PATH="/usr/local/opt/openssl/bin:$PATH"' >> ~/.bash_profileFor compilers to find openssl you may need to set:export LDFLAGS="-L/usr/local/opt/openssl/lib"export CPPFLAGS="-I/usr/local/opt/openssl/include"==> Summary
?  /usr/local/Cellar/openssl/1.0.2q: 1,794 files, 12.3MB

得到的提示和之前是一样的，事实也证明了，按brew的提示信息作link或者设置路径之类的工作没用，例如：（我的openssl安装路径是：/usr/local/Cellar/openssl/1.0.2q/）

$ brew link openssl
$ echo 'export PATH="/usr/local/Cellar/openssl/1.0.2q/bin:$PATH"' >> 
$ export LDFLAGS="-L/usr/local/Cellar/openssl/1.0.2q/lib"
$ export CPPFLAGS="-I/usr/local/Cellar/openssl/1.0.2q/include"

看似进入了死胡同！

上网搜！Bing，keyword：Homebrew openssl devel

终于找到一篇文章！
OpenSSL, OS X “El Capitan” and Brew

经测试，完美解决问题。
关键的两个步骤：

Step 1:
建立文件的链接（替身），取代设置环境变量（原文：And now we’ll link it into our public area so you don’t have to figure out the magic environment variable to set while building your favorite OpenSSL-backed library:）
将“/opt/openssl/”替换为实际安装路径，我的路径是：/usr/local/Cellar/openssl/1.0.2q/，那么下面代码中的"…/opt/openssl/“就应该是”…/Cellar/openssl/1.0.2q/"

$ cd /usr/local/include
$ ln -s ../opt/openssl/include/openssl .

Step 2:
某些情况下，库文件路径也必须做修改，没有更好的办法，只能用笨方法，作文件的链接（原文：I have found in some cases that the library path must also be amended. I haven’t figured this one out yet in the general case, but this always works, even though it’s a mess:）
将“/opt/openssl/”替换为实际安装路径，我的路径是：/usr/local/Cellar/openssl/1.0.2q/，那么下面代码中的"…/opt/openssl/“就应该是”…/Cellar/openssl/1.0.2q/"

$ cd /usr/local/lib
$ for i in ../opt/openssl/lib/lib*; do ln -vs $i .; done
./libcrypto.1.0.0.dylib -> ../opt/openssl/lib/libcrypto.1.0.0.dylib
./libcrypto.a -> ../opt/openssl/lib/libcrypto.a
./libcrypto.dylib -> ../opt/openssl/lib/libcrypto.dylib
./libssl.1.0.0.dylib -> ../opt/openssl/lib/libssl.1.0.0.dylib
./libssl.a -> ../opt/openssl/lib/libssl.a
./libssl.dylib -> ../opt/openssl/lib/libssl.dylib

用之前的一段读取https网页的代码测试

$ python3
Python 3.7.2 (default, Feb 12 2019, 08:16:11) 
[Clang 9.0.0 (clang-900.0.39.2)] on darwin
Type "help", "copyright", "credits" or "license" for more information.
>>> import ssl
>>> from urllib.request import urlopen
>>> WORD_URL = "https://learncodethehardway.org/words.txt"
>>> WORDS = []
>>> for word in urlopen(WORD_URL).readlines():
...     WORDS.append(str(word.strip(), encoding="utf-8"))
... 
>>> print (WORDS)
['account', 'achiever', 'actor', 'addition', 'adjustment', 'advertisement', 'advice', 'aftermath', 'agreement', 'airplane', 'airport', 'alarm', 'amount', 'amusement', 'angle', 'animal', 'answer', 'ant', 'apparatus', 'apparel', 'apple', 'appliance', 'approval', 'arch', 'argument', 'arithmetic', 'arm', 'army', 'art', 'attack', 
# 下略...