TypeError: write() got an unexpected keyword argument 'pretty_print'

Question

I am writing a python script which will append a new Tag/elment in config.xml of my jenkins job.

This is how my script looks like:-

#!/usr/bin/python

import os, fnmatch, pdb, re, string, fileinput, sys
from lxml import etree
def find(pattern, path):
result = []
for root, dirs, files in os.walk(path):
    for name in files:
        if fnmatch.fnmatch(name, pattern):
            result.append(os.path.join(root, name))
return result

finalresult = find('config.xml', './')
print finalresult
def writexml(filepath):
tree = etree.parse(filepath)
root = tree.getroot()
a=[]
for v in root.iter('publishers'):
        for a in v:
            if a.tag == "hudson.plugins.emailext.ExtendedEmailPublisher":
                t1=etree.SubElement(v,'org.jenkinsci.plugins.postbuildscript.PostBuildScript',{'plugin':"postbuildscript@017"})
                t2=etree.SubElement(t1,"buildSteps")
                t3=etree.SubElement(t2,'hudson.tasks.Shell')
                t4=etree.SubElement(t3,"command")
                t4.text = "bash -x /d0/jenkins/scripts/parent-pom-enforcer.sh"
                t5 = etree.SubElement(t1,'scriptOnlyIfSuccess')
                t5.text = "false"
                t6 = etree.SubElement(t1,'scriptOnlyIfFailure')
                t6.text = "false"
                t7= etree.SubElement(t1,'markBuildUnstable')
                t7.text = "true"

tree.write(filepath,pretty_print=True)

findMavenProject=[]
for i in finalresult:
tree = etree.parse(i)
root = tree.getroot()
for v in  root.iter('hudson.tasks.Maven'):
    if v.tag == "hudson.tasks.Maven":
        writexml(i)
        findMavenProject.append(i)
print findMavenProject

When I execute this script, I get following error:

  running with cElementTree on Python 2.5+
  ['./jen1/config.xml', './jen2/config.xml', './jen3/config.xml',     './jen4/config.xml']
  Traceback (most recent call last):
  File "./find-test.py", line 50, in <module>
  writexml(i)
  File "./find-test.py", line 41, in writexml
  tree.write(filepath,pretty_print=True)
  TypeError: write() got an unexpected keyword argument 'pretty_print'

I googled this error and found that, I should use "lxml". I used it but even after that I am getting the same error. I am using Python 2.7.6 version..

Any clue?

Answer 1

The tree.write(filepath,pretty_print=True) was wrong.

The right way: tree.write(filepath) or tree.tostring(root, pretty_print=True) .

---

Detail explaination:

tree was a ElementTree Objects , who's write has no pretty_print argument.

write(file, encoding="us-ascii", xml_declaration=None, default_namespace=None, method="xml")

Writes the element tree to a file, as XML. file is a file name, or a file object opened for writing. encoding [1] is the output encoding (default is US-ASCII). xml_declaration controls if an XML declaration should be added to the file. Use False for never, True for always, None for only if not US-ASCII or UTF-8 (default is None). default_namespace sets the default XML namespace (for “xmlns”). method is either "xml", "html" or "text" (default is "xml"). Returns an encoded string.

xml.etree.ElementTree.Element docs

---

UPDATE

To answer another question, Pretty printing XML in Python :

import xml.dom.minidom

my_xml_doc = xml.dom.minidom.parse(xml_fname) # or xml.dom.minidom.parseString(xml_string)
pretty_xml_as_string = my_xml_doc.toprettyxml()

---

UPDATE2

lxml.etree does have the pretty_print argument as follows:

etree.tostring(root, pretty_print=True)

lxml docs

special thanks to @RemcoGerlich

Answer 2

Python's standard library xml.etree.ElementTree.write() does not have the pretty_print argument.

The version of that method that is in recent versions of lxml does . I just tested it with lxml 3.3.3, and the docs at http://lxml.de/tutorial.html#serialisation mention it.

You are either using an old version of lxml, or somehow still using the standard library's older copy of the library.

Answer 3

The issue with below code is that it creates duplicate empty lines with tabs. if you are trying to edit the existing xml.

import xml.dom.minidom
xml = xml.dom.minidom.parse(xml_fname) # or xml.dom.minidom.parseString(xml_string)
pretty_xml_as_string = xml.toprettyxml()

Solution:- I tried below code and it worked for me.

from lxml import etree as ET
import xml.dom.minidom      
def writexml(filepath):
    parser = ET.XMLParser(resolve_entities=False, strip_cdata=False)
    tree = ET.parse(filepath, parser)
    root = tree.getroot()
    a=[]     
    for v in root.iter('publishers'):
        for a in v:
            if a.tag == "hudson.plugins.emailext.ExtendedEmailPublisher":
                t1=ET.SubElement(v,'org.jenkinsci.plugins.postbuildscript.PostBuildScript',{'plugin':"postbuildscript@0.17"})
                t2=ET.SubElement(t1,"buildSteps")
                t3=ET.SubElement(t2,'hudson.tasks.Shell')
                t4=ET.SubElement(t3,"command")
                t4.text = "bash -x /d0/jenkins/scripts/parent-pom-enforcer.sh"
                t5 = ET.SubElement(t1,'scriptOnlyIfSuccess')
                t5.text = "false"
                t6 = ET.SubElement(t1,'scriptOnlyIfFailure')
                t6.text = "false"
                t7= ET.SubElement(t1,'markBuildUnstable')
                t7.text = "true"
    xml1 = xml.dom.minidom.parseString(ET.tostring(root, pretty_print=True))
    pretty_xml_as_string = xml1.toprettyxml()
    f = open(filepath, "w")
    for v in str(pretty_xml_as_string).split("\n"):
        if v.strip():
            f.write(v+"\n")
    f.close()

writexml('test.xml') #provide full path of the file as arg to function writexml.