Processing xml document in python using libxml

Processing xml document in python using libxml

I had to spent sometimes to gather information about processing xml document in python. There are several different libraries to use, such as minidom, libxml, etree, etc. During my work, I had been working with xpath, so I need xpath support in the built-in library that I work with, so I chose libxml. It is difficult for me to gather information on how to use that API. There are minimum documentations, guides, examples, and tutorials out there.
After spending sometimes, I became familiar on using it. I am writing this, so other people could simply learn on how to use libxml in more realistic situation. Many examples I found in the internet is way too basic, and does not suit my need.


example 1:
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import sys
import libxml2

def main():
 doc = libxml2.parseFile("data.xml")
 ctxt = doc.xpathNewContext()
 # get student elements in xml doc
 res = ctxt.xpathEval("//student")
 # output all properties for "student" element using xpath
 sys.stdout.write(res[0].get_properties().content + "\n")

 for chld in res[0].children:
     if chld.type == "element":
             # output all information within the child element
             sys.stdout.write(chld.content + "\n")

 doc.freeDoc()
 ctxt.xpathFreeContext()

if __name__ == '__main__':
 main()

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example 2:
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import sys
import libxml2

def main():
 doc = libxml2.parseFile("layout.xml")
 ctxt = doc.xpathNewContext()
 # get all "property" element that has attribute "Location",
 # which parent is "object" element that has attribute "pickList*"
 res = ctxt.xpathEval("//Object[starts-with(@name,'pickList')]/Property[@name='Location']")
 for r in res:
     sys.stdout.write(r.content + "\n")

 sys.stdout.write(str(len(res)))

 doc.freeDoc()
 ctxt.xpathFreeContext()

if __name__ == '__main__':
 main()

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It is also useful to see the source code of libxml.py, just to see what's going on under the hood.

Not long after writing this post, I found even better xml API, which is lxml. I will make separate post about this wonderful xml API for python.