python第三方库lxml使用笔记
1. 源码安装 curl -v --cacert ./https-ca/cacert.pem https://pypi./packages/source/l/lxml/lxml-3.3.3.tar.gz#md5=f2675837b4358a5ecab5fd9a783fd0e5 -o lxml-3.3.3.tar.gz0?2 ?0?2 ?0?2 ?0?2 其中:--cacert ./https-ca/cacert.pem指定我机器上https认证文件的全路径,其它机器则该路径需要修改。关于认证文件的获取方法,可参考我之前写的这篇笔记。 0?2 ?0?2 ?0?2 ?0?2 下载完成后解压,由INSTALL.txt可知,这货安装前需要预先装好libxml2和libxslt两个包,于是继续折腾:从 xmlsoft.org官网 下载libxml2和libxslt的最新版源码后分别解压安装。 0?2 ?0?2 ?0?2 ?0?2 安装时的注意事项: 0?2 ?0?2 ?0?2 ?0?2 a. 先装libxml2,后装libxslt,否则安装libxslt时报错 0?2 ?0?2 ?0?2 ?0?2 b. 执行./configure时,可通过参数--with-python=[DIR]指定自己想bind的python全路径(在多人共用的机器上很有必要指定) 0?2 ?0?2 ?0?2 ?0?2 c. make libxslt源码前,需通过./configure中指定python全路径及libxml2的3个参数,参考命令如下: /configure --prefix=/home/slvher/tools/3rd-libs-for-py/libxslt-1.1.28/ --with-python=/home/slvher/tools/python-2.7.5/bin/python --with-libxml-prefix=/home/slvher/tools/3rd-libs-for-py/libxml2-2.9.0 --with-libxml-include-prefix=/home/slvher/tools/3rd-libs-for-py/libxml2-2.9.0/include/ --with-libxml-libs-prefix=/home/slvher/tools/3rd-libs-for-py/libxml2-2.9.0/lib/0?2 ?0?2 ?0?2 ?0?2 libxml2和libxslt安装成功后,进入lxml源码目录,在某临时目录(假设为/home/slvher/tools/lxml-package)下安装lxml,参考命令如下: python ./setup.py install root=/home/slvher/tools/lxml-package --with-xml2-config=/home/slvher/tools/3rd-libs-for-py/libxml2-2.9.0/bin/xml2-config --with-xslt-config=/home/slvher/tools/3rd-libs-for-py/libxslt-1.1.28/bin/xslt-config0?2 ?0?2 ?0?2 ?0?2 将该临时安装目录下lxml和lxml-3.3.3-py2.7.egg-info两个文件夹cp至python安装目录的site-packages路径下,至此,lxml安装完成 0?2 ?0?2 ?0?2 ?0?2 个人体会:如果机器系统有现成的包管理工具或easy_install之类的工具支持一键安装,并且自己不想折腾,建议不要通过源码安装,对于老手来说,这个过程实在是有点浪费时间 -_- 2. 测试是否可用 0?2 ?0?2 ?0?2 ?0?2 lxml及其egg-info拷贝到python的site-packages目录后,可以在python中试用lxml: >>> from lxml import etree Traceback (most recent call last): File "<stdin>", line 1, in <module> ImportError: /home/slvher/tools/python-2.7.5/lib/python2.7/site-packages/lxml/etree.so: undefined symbol: exsltStrXpathCtxtRegister0?2 ?0?2 ?0?2 ?0?2 符号找不到,难道是安装有问题? 0?2 ?0?2 ?0?2 ?0?2 进入python的site-packages目录,终端输入命令ldd lxml/etree.so,输出结果如下: lxml/etree.so: /usr/lib64/libxslt.so.1: no version information available (required by lxml/etree.so) lxml/etree.so: /usr/lib64/libxslt.so.1: no version information available (required by lxml/etree.so) lxml/etree.so: /usr/lib64/libxslt.so.1: no version information available (required by lxml/etree.so) lxml/etree.so: /usr/lib64/libxslt.so.1: no version information available (required by lxml/etree.so) lxml/etree.so: /usr/lib64/libxslt.so.1: no version information available (required by lxml/etree.so) lxml/etree.so: /usr/lib64/libxslt.so.1: no version information available (required by lxml/etree.so) lxml/etree.so: /usr/lib64/libxslt.so.1: no version information available (required by lxml/etree.so) libxslt.so.1 => /usr/lib64/libxslt.so.1 (0x00007fd95d51f000) libexslt.so.0 => /usr/lib64/libexslt.so.0 (0x00007fd95d40e000) libxml2.so.2 => /home/slvher/tools/3rd-libs-for-py/libxml2-2.9.0/lib/libxml2.so.2 (0x00007fd95d1c2000) libz.so.1 => /usr/lib64/libz.so.1 (0x00007fd95d0ae000) libm.so.6 => /lib64/tls/libm.so.6 (0x00007fd95cf28000) libpthread.so.0 => /lib64/tls/libpthread.so.0 (0x00007fd95ce13000) libc.so.6 => /lib64/tls/libc.so.6 (0x00007fd95cbde000) libgcrypt.so.11 => /usr/lib64/libgcrypt.so.11 (0x00007fd95ca94000) libgpg-error.so.0 => /usr/lib64/libgpg-error.so.0 (0x00007fd95c991000) libdl.so.2 => /lib64/libdl.so.2 (0x00007fd95c88d000) /lib64/ld-linux-x86-64.so.2 (0x000000302ad00000) libnsl.so.1 => /lib64/libnsl.so.1 (0x00007fd95c776000)0?2 ?0?2?0?2 ?0?2 ?0?2可见,etree.so中依赖的libxslt.so.1和libexslt.so.0指向了机器/usr/lib64/路径下老版本的so库 0?2 ?0?2 ?0?2 ?0?2 解决办法如下: export LD_LIBRARY_PATH=/home/slvher/tools/3rd-libs-for-py/libxml2-2.9.0/lib/:/home/slvher/tools/3rd-libs-for-py/libxslt-1.1.28/lib/:$LD_LIBRARY_PATH0?2 ?0?2 ?0?2 ?0?2 然后在python终端执行from lxml import etree 0?2 ?0?2 ?0?2 ?0?2 一切正常 0?2 ?0?2 ?0?2 ?0?2 提示: 0?2 ?0?2 ?0?2 ?0?2 若想在其它机器上使用lxml又不想安装,则可以将已装有lxml包的python的site-packages目录中与lxml有关的2个文件夹拷贝至目标机器python的site-packages目录下,然后将etree依赖的3个so库拷贝至目标机器的某指定路径下,最后通过LD_LIBRARY_PATH将该路径包含至python包对so的搜索路径中即可。
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