周海漢 2016.5.25

用python做資料分析或爬蟲抓包，離不開高效的lxml。但lxml安裝在mac下卻會失敗。

% pip install lxml
Collecting lxml
  Using cached lxml-3.6.0.tar.gz
Building wheels for collected packages: lxml
  Running setup.py bdist_wheel for lxml ... error
  Complete output from command /usr/bin/python -u -c "import setuptools, tokenize;__file__='/private/var/folders/zf/jf20tj1j49nflxqkfrvf4d1r0000gn/T/pip-build-UOgePA/lxml/setup.py';exec(compile(getattr(tokenize, 'open', open)(__file__).read().replace('\r\n', '\n'), __file__, 'exec'))" bdist_wheel -d /var/folders/zf/jf20tj1j49nflxqkfrvf4d1r0000gn/T/tmpc6WLwjpip-wheel- --python-tag cp27:
  Building lxml version 3.6.0.
...
cc -fno-strict-aliasing -fno-common -dynamic -arch x86_64 -arch i386 -g -Os -pipe -fno-common -fno-strict-aliasing -fwrapv -DENABLE_DTRACE -DMACOSX -DNDEBUG -Wall -Wstrict-prototypes -Wshorten-64-to-32 -DNDEBUG -g -fwrapv -Os -Wall -Wstrict-prototypes -DENABLE_DTRACE -arch x86_64 -arch i386 -pipe -I/usr/include/libxml2 -Isrc/lxml/includes -I/System/Library/Frameworks/Python.framework/Versions/2.7/include/python2.7 -c src/lxml/lxml.etree.c -o build/temp.macosx-10.10-intel-2.7/src/lxml/lxml.etree.o -w -flat_namespace
  In file included from src/lxml/lxml.etree.c:320:
  src/lxml/includes/etree_defs.h:14:10: fatal error: 'libxml/xmlversion.h' file not found
  #include "libxml/xmlversion.h"
           ^
  1 error generated.
  Compile failed: command 'cc' failed with exit status 1
  creating var
  creating var/folders
  creating var/folders/zf
  creating var/folders/zf/jf20tj1j49nflxqkfrvf4d1r0000gn
  creating var/folders/zf/jf20tj1j49nflxqkfrvf4d1r0000gn/T
  cc -I/usr/include/libxml2 -I/usr/include/libxml2 -c /var/folders/zf/jf20tj1j49nflxqkfrvf4d1r0000gn/T/xmlXPathInitzbnoga.c -o var/folders/zf/jf20tj1j49nflxqkfrvf4d1r0000gn/T/xmlXPathInitzbnoga.o
  /var/folders/zf/jf20tj1j49nflxqkfrvf4d1r0000gn/T/xmlXPathInitzbnoga.c:1:10: fatal error: 'libxml/xpath.h' file not found
  #include "libxml/xpath.h"
           ^
  1 error generated.
  *********************************************************************************
  Could not find function xmlCheckVersion in library libxml2. Is libxml2 installed?
  Perhaps try: xcode-select --install
  *********************************************************************************
  error: command 'cc' failed with exit status 1

  ----------------------------------------
  Failed building wheel for lxml
error: command 'cc' failed with exit status 1
 

lxml依賴libxml2. 需要下載編譯libxml2

一種方式，直接下載libxml2.9.3原始碼

libxml2-2.9.3 % ./configure –with-python=/System/Library/Frameworks/Python.framework/Versions/2.7/

make&make install

但執行pip install lxml還是報同樣的錯誤。

用brew 安裝 libxml2

libxml2-2.9.3 % sudo brew install libxml2 --with-python
Password:
==> Downloading http://xmlsoft.org/sources/libxml2-2.9.3.tar.gz
######################################################################## 100.0%
==> ./configure --prefix=/usr/local/Cellar/libxml2/2.9.3 --without-python --without-lzma
==> make
==> make install
==> python setup.py install --prefix=/usr/local/Cellar/libxml2/2.9.3
==> Caveats
This formula is keg-only, which means it was not symlinked into /usr/local.

OS X already provides this software and installing another version in
parallel can cause all kinds of trouble.

Generally there are no consequences of this for you. If you build your
own software and it requires this formula, you'll need to add to your
build variables:

    LDFLAGS:  -L/usr/local/opt/libxml2/lib
    CPPFLAGS: -I/usr/local/opt/libxml2/include


If you need Python to find bindings for this keg-only formula, run:
  echo /usr/local/opt/libxml2/lib/python2.7/site-packages >> /usr/local/lib/python2.7/site-packages/libxml2.pth
  mkdir -p /Users/zhh/Library/Python/2.7/lib/python/site-packages
  echo 'import site; site.addsitedir("/usr/local/lib/python2.7/site-packages")' >> /Users/zhh/Library/Python/2.7/lib/python/site-packages/homebrew.pth
==> Summary