CentOS 6 安装 python 2.7 和 mod_wsgi 运行pyocr[tesseract]

　　最新版本的tesseract-ocr 3.0.4 需要运行于python2.7版本以上，因此需要升级系统中默认的2.6版本python及Mod_WSGI

1，下载安装Python-2.7.10

>tar xJvf  Python-2.7.10.tar6.xz
>cd  Python-2.7.10
# 这里，必须用–enable-shared，生成动态库，否则会遇到wsgi不能编译的问题。
>./configure --enable-shared  
>make && make install
#替换原来的默认python
>mv /usr/bin/python /usr/bin/python2.6
>ln -s /usr/local/bin/python2.7 /usr/bin/python
#设置lib路径
>ldconfig /usr/local/lib
#查看python状态
>python -V

2，安装python2.7的mod_wsgi

>pip install mod_wsgi

如果安装python2.7.10时没有加入--enable-shared参数，安装mod_wsgi时就会报如下错误:"recompile with -fPIC"

......
/usr/bin/ld: /usr/local/lib/libpython2.7.a(abstract.o): relocation R_X86_64_32 against `.rodata.str1.8' can not be used when making a shared object; recompile with -fPIC
/usr/local/lib/libpython2.7.a: could not read symbols: Bad value
collect2: ld returned 1 exit status
apxs:Error: Command failed with rc=65536

3, 替换系统默认Mod_wsgi

>mv /usr/lib64/httpd/modules/mod_wsgi.so /usr/lib64/httpd/modules/mod_wsgi.so.origin 
>ln -s /usr/local/lib/python2.7/site-packages/mod_wsgi/server/mod_wsgi-py27.so /usr/lib64/httpd/modules/mod_wsgi.so

4，运行apache，报错找不到ocr模块，然而在调试环境下没有问题，经查看pyocr的源码发现，pyocr.get_available_tools()  是通过在环境变量os.environ["PATH"]中查看有没有tesseract命令，因此需要将tesseract的安装路径/usr/local/bin/tesseract加入PATH中，然后重新启动，或者在python程序中自己加入路径/usr/local/bin