What's the best way to logically compare two XML files?

Question

I want to compare two XML files logically. That means that following text lines should be the same for the comparison tool:

1.

<test><hello/><test/>

2.

<test>




       <hello/>




<test/>

I'm a Windows developer and tried some comparison tools now: Beyond Compare, WinMerge, Total Commander, but all of them compare XML like a normal text comparison tool.

Are there any other tools or approaches I can take?

Answer 1

Beyond Compare does work. Just download the XML tidied from here http://www.scootersoftware.com/download.php?zz=kb_moreformats_alt Also there are a couple other options as well.

Answer 2

Most of the time, your language's standard xml libraries allow you to iterate through the nodes. If you just use the nodes, white-space is irrelevant anyways. All you need is one recursive function at that point and you are finished. I know in C#, for instance, you can load an XmlDocument and then grab each XmlNode of the document then the child nodes of each parent node. Java has the same capabilities.

Answer 3

A simple groovy script follows that compares two strings to give you an idea of the things you can customise.

import org.custommonkey.xmlunit.XMLUnit;


def xml1 = 
    '''
    <test><hello/><data>text</data><data2>text2</data2><cdata>cdatatext</cdata></test>
    '''

def xml2 =
    '''
    <test>
        <hello/>



        <data>text</data>

        <data2>
        text2
        </data2>

        <cdata><![CDATA[cdatatext]]></cdata>

        <!-- comment -->

        </test>
    '''

// most likely comparison you want
XMLUnit.setIgnoreWhitespace(true)
XMLUnit.setIgnoreComments(true)
XMLUnit.setIgnoreDiffBetweenTextAndCDATA(true)
XMLUnit.setNormalizeWhitespace(true)

System.out.println(XMLUnit.compareXML(xml1, xml2))

Here is a version that compares two files passed as arguments

import org.custommonkey.xmlunit.XMLUnit;

def xml1 = new FileReader(args[0])
def xml2 = new FileReader(args[1])

XMLUnit.setIgnoreWhitespace(true)
XMLUnit.setIgnoreComments(true)
XMLUnit.setIgnoreDiffBetweenTextAndCDATA(true)
XMLUnit.setNormalizeWhitespace(true)

System.out.println(XMLUnit.compareXML(xml1, xml2))

Answer 4

One workaround would be to load both using the same XML parser, then have the parser write a new file with the same whitespace options -- this should effectively standardize the text output and let the text comparison tools work.