This is actually a reasonably challenging problem (due to what "difference" means often being in the eye of the beholder here, as there will be semantically "equivalent" information that you probably don't want marked as differences).
You could try using xmldiff, which is based on work in the paper Change Detection in Hierarchically Structured Information.
Answer from Nick Bastin on Stack OverflowThis is actually a reasonably challenging problem (due to what "difference" means often being in the eye of the beholder here, as there will be semantically "equivalent" information that you probably don't want marked as differences).
You could try using xmldiff, which is based on work in the paper Change Detection in Hierarchically Structured Information.
My approach to the problem was transforming each XML into a xml.etree.ElementTree and iterating through each of the layers. I also included the functionality to ignore a list of attributes while doing the comparison.
The first block of code holds the class used:
import xml.etree.ElementTree as ET
import logging
class XmlTree():
def __init__(self):
self.hdlr = logging.FileHandler('xml-comparison.log')
self.formatter = logging.Formatter('%(asctime)s %(levelname)s %(message)s')
@staticmethod
def convert_string_to_tree( xmlString):
return ET.fromstring(xmlString)
def xml_compare(self, x1, x2, excludes=[]):
"""
Compares two xml etrees
:param x1: the first tree
:param x2: the second tree
:param excludes: list of string of attributes to exclude from comparison
:return:
True if both files match
"""
if x1.tag != x2.tag:
self.logger.debug('Tags do not match: %s and %s' % (x1.tag, x2.tag))
return False
for name, value in x1.attrib.items():
if not name in excludes:
if x2.attrib.get(name) != value:
self.logger.debug('Attributes do not match: %s=%r, %s=%r'
% (name, value, name, x2.attrib.get(name)))
return False
for name in x2.attrib.keys():
if not name in excludes:
if name not in x1.attrib:
self.logger.debug('x2 has an attribute x1 is missing: %s'
% name)
return False
if not self.text_compare(x1.text, x2.text):
self.logger.debug('text: %r != %r' % (x1.text, x2.text))
return False
if not self.text_compare(x1.tail, x2.tail):
self.logger.debug('tail: %r != %r' % (x1.tail, x2.tail))
return False
cl1 = x1.getchildren()
cl2 = x2.getchildren()
if len(cl1) != len(cl2):
self.logger.debug('children length differs, %i != %i'
% (len(cl1), len(cl2)))
return False
i = 0
for c1, c2 in zip(cl1, cl2):
i += 1
if not c1.tag in excludes:
if not self.xml_compare(c1, c2, excludes):
self.logger.debug('children %i do not match: %s'
% (i, c1.tag))
return False
return True
def text_compare(self, t1, t2):
"""
Compare two text strings
:param t1: text one
:param t2: text two
:return:
True if a match
"""
if not t1 and not t2:
return True
if t1 == '*' or t2 == '*':
return True
return (t1 or '').strip() == (t2 or '').strip()
The second block of code holds a couple of XML examples and their comparison:
xml1 = "<note><to>Tove</to><from>Jani</from><heading>Reminder</heading><body>Don't forget me this weekend!</body></note>"
xml2 = "<note><to>Tove</to><from>Daniel</from><heading>Reminder</heading><body>Don't forget me this weekend!</body></note>"
tree1 = XmlTree.convert_string_to_tree(xml1)
tree2 = XmlTree.convert_string_to_tree(xml2)
comparator = XmlTree()
if comparator.xml_compare(tree1, tree2, ["from"]):
print "XMLs match"
else:
print "XMLs don't match"
Most of the credit for this code must be given to syawar
» pip install xmldiff
Best ways to compare xml files with python
bash - how to compare two xml files having same data in different lines? - Unix & Linux Stack Exchange
Question on parsing and comparing two different XML docs.
Comparing xml/html files in Beautiful Soup
At a very high level, this seems like a use case where sets would be helpful. Create one set of saved events and one set of live events, and then use the difference or symmetric_difference functions to pull out the changes.
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Two approaches that I use are (a) to canonicalize both XML files and then compare their serializations, and (b) to use the XPath 2.0 deep-equal() function. Both approaches are OK for telling you whether the files are the same, but not very good at telling you where they differ.
A commercial tool that specializes in this problem is DeltaXML.
If you have things that you consider equivalent, but which aren't equivalent at the XML level - for example, elements in a different order - then you may have to be prepared to do a transformation to normalize the documents before comparison.
Good answer here:
Question: How can I diff two XML files? | Super User
Answer: How can I diff two XML files? | Super User
$ xmllint --format --exc-c14n one.xml > 1.xml
$ xmllint --format --exc-c14n two.xml > 2.xml
$ diff 1.xml 2.xml
Apologies for any failure to adhere to serverfault conventions ... I'm sure someone will let me know and I will amend appropriately.
You can achieve what you want with the help of a small Python script (you'll need Python installed, as well as the lxml toolkit).
tagsort.py:
#!/usr/bin/python
import sys
from lxml import etree
filename, tag = sys.argv[1:]
doc = etree.parse(filename, etree.XMLParser(remove_blank_text=True))
root = doc.getroot()
root[:] = sorted(root, key=lambda el: el.findtext(tag))
print etree.tostring(doc, pretty_print=True)
This script sorts the first-level elements under the XML document root by the content of a second-level element, sending the result to stdout. It's called like this:
$ python tagsort.py filename tag
Once you've got that, you can use process substitution to get a diff based on its output (I've added one element and changed another in your example files to show a non-empty result):
$ diff <(python tagsort.py file1 Id) <(python tagsort.py file2 Id)
4a5
> <AddedTag>Something</AddedTag>
17c18
< <Role>X</Role>
---
> <Role>S</Role>
I had a similar problem and I eventually found: https://superuser.com/questions/79920/how-can-i-diff-two-xml-files
That post suggests doing a canonical xml sort then doing a diff. The following should work for you if you are on linux, mac, or if you have windows something like cygwin installed:
$ xmllint --c14n File1.xml > 1.xml
$ xmllint --c14n File2.xml > 2.xml
$ diff 1.xml 2.xml