Python XML Parser not Returning XML Elemements - python

I am trying to find a way to use Python to parse data from several .xml files that contain part numbers and descriptions for a system my team is working on. Here's what the files look like:
Note: Actual data sanitized for confidentiality reasons.
<DOCUMENT>
<config>
<lruname>NFS</lruname>
<swpn>123-A-456-7890</swpn>
<swname>00 NFS ABC DEFGHI XYZ JKL</swname>
<swver>Appid: abc-defghi-xyz PN: 123-A-456-7890</swver>
</config>
</DOCUMENT>
I'd like to pull the and datatypes from several of these files into .csv format. My initial thought was to try to parse these data types out into a dictionary using the built in xml.etree library, but for some reason it's not finding the elements:
import xml.etree.ElementTree as ET
data = '''
<DOCUMENT>
<config>
<lruname>NFS</lruname>
<swpn>123-A-456-7890</swpn>
<swname>00 NFS ABC DEFGHI XYZ JKL</swname>
<swver>Appid: abc-defghi-xyz PN: 123-A-456-7890</swver>
</config>
</DOCUMENT>
'''
tree = ET.fromstring(data)
PartNo = tree.find('swpn')
Desc = tree.find('swname')
print(PartNo)
The above code returns 'None' for some reason, but I would expect it to return the xml element I'm calling.

I think you're missing the config level in your XML hierarchy, you could do:
part_number = tree.find('config').find('swpn').text
part_desc = tree.find('config').find('swname').text
Alternately you can loop through all the elements if you don't want to have to know the structure and use conditionals to find the elements you care about with tree.iter.
for e in tree.iter():
if e.tag == 'sqpn':
part_number = e.text
if e.tag == 'swname':
part_desc = e.text

ElementTree and etree's find functionality searchers for direct children.
You can still use it by specifying the entire branch:
tree.find('config').find('swpn')
tree.find('config/swpn')
If you always want to look for swpn, but disregard the structure (e.g. you don't know if it's going to be a child of config), you might find it easier to use the xpath functionality in etree (and not in ElementTree):
tree = etree.fromstring(data)
tree.xpath('//swpn')
In this case, the // basically mean that you are looking for elements in tree, no matter where they are
If the xml files are small, and you don't care about performance, you can use minidom which IMHO is more convenient compared to lxml. In this case, your code could be something like this:
from xml.dom.minidom import parseString
xml = parseString(data)
PartNo = xml.getElementsByTagName('swpn')[0]
Desc = xml.getElementsByTagName('swname')[0]
print(PartNo.firstChild.nodeValue)

Related

can we search multiple pattern using etree findall() in xml?

For my case, I have to find few elements in the XML file and update their values using the text attribute. For that, I have to search xml element A, B and C. My project is using xml.etree and python language. Currently I am using:
self.get_root.findall(H/A/T)
self.get_root.findall(H/B/T)
self.get_root.findall(H/C/T)
The sample XML file:
<H><A><T>text-i-have-to-update</H></A></T>
<H><B><T>text-i-have-to-update</H></B></T>
<H><C><T>text-i-have-to-update</H></C></T>
As we can notice, only the middle element in the path is different. Is there a way to optimize the code using something like self.get_root.findall(H|(A,B,C)|T)? Any guidance in the right direction will do! Thanks!
I went through the similar question: XPath to select multiple tags but it didn't work for my case
Update: maybe regular expression inside the findall()?
The html in your question is malformed; assuming it's properly formatted (like below), try this:
import xml.etree.ElementTree as ET
data = """<root>
<H><A><T>text-i-have-to-update</T></A></H>
<H><B><T>text-i-have-to-update</T></B></H>
<H><C><T>text-i-have-to-update</T></C></H>
</root>"""
doc = ET.fromstring(data)
for item in doc.findall('.//H//T'):
item.text = "modified text"
print(ET.tostring(doc).decode())
Output:
<root>
<H><A><T>modified text</T></A></H>
<H><B><T>modified text</T></B></H>
<H><C><T>modified text</T></C></H>
</root>

Parsing XML in python: selecting an attribute given that a child node has a specific attribute

Given the xml
xmlstr = '''
<myxml>
<Description id="10">
<child info="myurl"/>
</Description>
</myxml>'
I'd like to get the id of Description only where child has an attribute of info.
import xml.etree.ElementTree as ET
root = ET.fromstring(xmlstr)
a = root.find(".//Description/[child/#info]")
print(a.attrib)
and changing the find to .//Description/[child[#info]]
both return an error of:
SyntaxError: invalid predicate
I know that etree only supports a subset of xpath, but this doesn't seem particularly weird - should this work? If so, what have I done wrong?!
Changing the find to .//Description/[child] does work, and returns
{'id': '10'}
as expected
You've definitely hit that XPath limited support limitation as, if we look at the source directly (looking at 3.7 source code), we could see that while parsing the Element Path expression, only these things in the filters are considered:
[#attribute] predicate
[#attribute='value']
[tag]
[.='value'] or [tag='value']
[index] or [last()] or [last()-index]
Which means that both of your rather simple expressions are not supported.
If you really want/need to stick with the built-in ElementTree library, one way to solve this would be with finding all Description tags via .findall() and filtering the one having a child element with info attribute.
You can also get those values as keys, which makes it a bit more structured approach to gather data:
import xml.etree.ElementTree as ET
root = ET.fromstring(xmlstr)
wht =root.find(".//Description")
wht.keys() #--> ['id']
wht.get('id') # --> '10'

Parsing and extracting field values from XML files

I have a couple of GB of log files in the XML format. What I am interested in is finding the rows with a specific command and extract the user that ordered the command.
Which is to say I want to check a particular field in all rows for a specific value and then extract an unknown value from another field on the same line. How do I go about doing that? (I've tried turning to documentation and other sources without understanding how it works.)
I currently use Python 2.7.15, but if 3.* is better or easier in any way I'll use that.
Here's an example of a row in a logfile that I'm interested in:
<?xml version="1.0" encoding="UTF-8"?>
<IHEYr4>
<UserAuthenticated>
<LocalUsername>User1</LocalUsername>
<Action>Login</Action>
</UserAuthenticated>
<Host>192.168.1.15</Host>
<TimeStamp>2018-01-18T02:31:00</TimeStamp>
</IHEYr4>
Using ElementTree
Demo:
x = """<?xml version="1.0" encoding="UTF-8"?>
<IHEYr4>
<UserAuthenticated>
<LocalUsername>User1</LocalUsername>
<Action>Login</Action>
</UserAuthenticated>
<Host>192.168.1.15</Host>
<TimeStamp>2018-01-18T02:31:00</TimeStamp>
</IHEYr4>
"""
import xml.etree.ElementTree as ET
xmlVal = ET.fromstring(x)
if xmlVal.find("UserAuthenticated/Action").text == 'Login':
print(xmlVal.find("Host").text, xmlVal.find("TimeStamp").text)
Output:
('192.168.1.15', '2018-01-18T02:31:00')

XML parsing in Python using Python 2 or 3

I'm just trying to write a simple program to allow me to parse some of the following XML.
So far in following examples I am not getting the results I'm looking for.
I encounter many of these XML files and I generally want the info after a handful of tags.
What's the best way using elementtree to be able to do a search for <Id> and grab what ever info is in that tag. I was trying things like
for Reel in root.findall('Reel'):
... id = Reel.findtext('Id')
... print id
Is there a way just to look for every instance of <Id> and grab the urn: etc that comes after it? Some code that traverses everything and looks for <what I want> and so on.
This is a very truncated version of what I usually deal with.
This didn't get what I wanted at all. Is there an easy just to match <what I want> in any XML file and get the contents of that tag, or do i need to know the structure of the XML well enough to know its relation to Root/child etc?
<Reel>
<Id>urn:uuid:632437bc-73f9-49ca-b687-fdb3f98f430c</Id>
<AssetList>
<MainPicture>
<Id>urn:uuid:46afe8a3-50be-4986-b9c8-34f4ba69572f</Id>
<EditRate>24 1</EditRate>
<IntrinsicDuration>340</IntrinsicDuration>
<EntryPoint>0</EntryPoint>
<Duration>340</Duration>
<FrameRate>24 1</FrameRate>
<ScreenAspectRatio>2048 858</ScreenAspectRatio>
</MainPicture>
<MainSound>
<Id>urn:uuid:1fce0915-f8c7-48a7-b023-36e204a66ed1</Id>
<EditRate>24 1</EditRate>
<IntrinsicDuration>340</IntrinsicDuration>
<EntryPoint>0</EntryPoint>
<Duration>340</Duration>
</MainSound>
</AssetList>
</Reel>
#Mata that worked perfectly, but when I tried to use that for different values on another XML file I fell flat on my face. For instance, what about this section of a file.I couldn't post the whole thing unfortunately. What if I want to grab what comes after KeyId?
<?xml version="1.0" encoding="UTF-8" standalone="no" ?><DCinemaSecurityMessage xmlns="http://www.digicine.com/PROTO-ASDCP-KDM-20040311#" xmlns:dsig="http://www.w3.org/2000/09/xmldsig#" xmlns:enc="http://www.w3.org/2001/04/xmlenc#">
<!-- Generated by Wailua Version 0.3.20 -->
<AuthenticatedPublic Id="ID_AuthenticatedPublic">
<MessageId>urn:uuid:7bc63f4c-c617-4d00-9e51-0c8cd6a4f59e</MessageId>
<MessageType>http://www.digicine.com/PROTO-ASDCP-KDM-20040311#</MessageType>
<AnnotationText>SPIDERMAN-3_FTR_S_EN-XX_US-13_51_4K_PH_20070423_DELUXE ~ KDM for Quvis-10010.pem</AnnotationText>
<IssueDate>2007-04-29T04:13:43-00:00</IssueDate>
<Signer>
<dsig:X509IssuerName>dnQualifier=BzC0n/VV/uVrl2PL3uggPJ9va7Q=,CN=.deluxe-admin-c,OU=.mxf-j2c.ca.cinecert.com,O=.ca.cinecert.com</dsig:X509IssuerName>
<dsig:X509SerialNumber>10039</dsig:X509SerialNumber>
</Signer>
<RequiredExtensions>
<Recipient>
<X509IssuerSerial>
<dsig:X509IssuerName>dnQualifier=RUxyQle0qS7qPbcNRFBEgVjw0Og=,CN=SM.QuVIS.com.001,OU=QuVIS Digital Cinema,O=QuVIS.com</dsig:X509IssuerName>
<dsig:X509SerialNumber>363</dsig:X509SerialNumber>
</X509IssuerSerial>
<X509SubjectName>CN=SM MD LE FM.QuVIS_CinemaPlayer-3d_10010,OU=QuVIS,O=QuVIS.com,dnQualifier=3oBfjTfx1me0p1ms7XOX\+eqUUtE=</X509SubjectName>
</Recipient>
<CompositionPlaylistId>urn:uuid:336263da-e4f1-324e-8e0c-ebea00ff79f4</CompositionPlaylistId>
<ContentTitleText>SPIDERMAN-3_FTR_S_EN-XX_US-13_51_4K_PH_20070423_DELUXE</ContentTitleText>
<ContentKeysNotValidBefore>2007-04-30T05:00:00-00:00</ContentKeysNotValidBefore>
<ContentKeysNotValidAfter>2007-04-30T10:00:00-00:00</ContentKeysNotValidAfter>
<KeyIdList>
<KeyId>urn:uuid:9851b0f6-4790-0d4c-a69d-ea8abdedd03d</KeyId>
<KeyId>urn:uuid:8317e8f3-1597-494d-9ed8-08a751ff8615</KeyId>
<KeyId>urn:uuid:5d9b228d-7120-344c-aefc-840cdd32bbfc</KeyId>
<KeyId>urn:uuid:1e32ccb2-ab0b-9d43-b879-1c12840c178b</KeyId>
<KeyId>urn:uuid:44d04416-676a-2e4f-8995-165de8cab78d</KeyId>
<KeyId>urn:uuid:906da0c1-b0cb-4541-b8a9-86476583cdc4</KeyId>
<KeyId>urn:uuid:0fe2d73a-ebe3-9844-b3de-4517c63c4b90</KeyId>
<KeyId>urn:uuid:862fa79a-18c7-9245-a172-486541bef0c0</KeyId>
<KeyId>urn:uuid:aa2f1a88-7a55-894d-bc19-42afca589766</KeyId>
<KeyId>urn:uuid:59d6eeff-cd56-6245-9f13-951554466626</KeyId>
<KeyId>urn:uuid:14a13b1a-76ba-764c-97d0-9900f58af53e</KeyId>
<KeyId>urn:uuid:ccdbe0ae-1c3f-224c-b450-947f43bbd640</KeyId>
<KeyId>urn:uuid:dcd37f10-b042-8e44-bef0-89bda2174842</KeyId>
<KeyId>urn:uuid:9dd7103e-7e5a-a840-a15f-f7d7fe699203</KeyId>
</KeyIdList>
</RequiredExtensions>
<NonCriticalExtensions/>
</AuthenticatedPublic>
<AuthenticatedPrivate Id="ID_AuthenticatedPrivate"><enc:EncryptedKey xmlns:enc="http://www.w3.org/2001/04/xmlenc#">
<enc:EncryptionMethod Algorithm="http://www.w3.org/2001/04/xmlenc#rsa-oaep-mgf1p">
<ds:DigestMethod xmlns:ds="http://www.w3.org/2000/09/xmldsig#" Algorithm="http://www.w3.org/2000/09/xmldsig#sha1"/>
</enc:EncryptionMethod>
The expression Reel.findtext('Id') only matches direct children of Reel. If you want to find all Id tags in your xml document, you can just use:
ids = [id.text for id in Reel.findall(".//Id")]
This would give you a list of all text nodes of all Id tags which are children of Reel.
edit:
Your updated example uses namespaces, in this case KeyId is in the default namespace (http://www.digicine.com/PROTO-ASDCP-KDM-20040311#), so to search for it you need to include it in your search:
from xml.etree import ElementTree
doc = ElementTree.parse('test.xml')
nsmap = {'ns': 'http://www.digicine.com/PROTO-ASDCP-KDM-20040311#'}
ids = [id.text for id in doc.findall(".//ns:KeyId", namespaces=nsmap)]
print(ids)
...
The xpath subset ElementTree supports is rather limited. If you want a more complete support, you should use lxml instead, it's xpath support is way more complete.
For example, using xpath to search for all KeyId tags (ignoring namespaces) and returning their text content directly:
from lxml import etree
doc = etree.parse('test.xml')
ids = doc.xpath(".//*[local-name()='KeyId']/text()")
print(ids)
...
It sounds like XPath might be right up your alley - it will let you query your XML document for exactly what you're looking for, as long as you know the structure.
Here's what I needed to do. This works for finding whatever I need.
for node in tree.getiterator():
... if 'KeyId' in node.tag:
... mylist = node.tag
... print(mylist)
...

Python minidom: How to access an element

I'm working on parsing an XML-Sheet in Python. The XML has a structure like this:
<layer1>
<layer2>
<element>
<info1></info1>
</element>
<element>
<info1></info1>
</element>
<element>
<info1></info1>
</element>
</layer2>
</layer1>
Without layer2, I have no problems to acess the data in info1. But with layer2, I'm really in trouble. Their I can adress info1 with: root.firstChild.childNodes[0].childNodes[0].data
So my thought was, that I can do it similiar like this:root.firstChild.firstChild.childNodes[0].childNodes[0].data
########## Solution
So this is how I solved my problem:
from xml.etree import cElementTree as ET
from xml.etree import cElementTree as ET
tree = ET.parse("test.xml")
root = tree.getroot()
for elem in root.findall('./layer2/'):
for node in elem.findall('element/'):
x = node.find('info1').text
if x != "abc":
elem.remove(node)
Don't use the minidom API if you can help it. Use the ElementTree API instead; the xml.dom.minidom documentation explicitly states that:
Users who are not already proficient with the DOM should consider using the xml.etree.ElementTree module for their XML processing instead.
Here is a short sample that uses the ElementTree API to access your elements:
from xml.etree import ElementTree as ET
tree = ET.parse('inputfile.xml')
for info in tree.findall('.//element/info1'):
print info.text
This uses an XPath expression to list all info1 elements that are contained inside a element element, regardless of their position in the overall XML document.
If all you need is the first info1 element, use .find():
print tree.find('.//info1').text
With the DOM API, .firstChild could easily be a Text node instead of an Element node; you always need to loop over the .childNotes sequence to find the first Element match:
def findFirstElement(node):
for child in node.childNodes:
if child.nodeType == node.ELEMENT_NODE:
return child
but for your case, perhaps using .getElementsByTagName() suffices:
root.getElementsByTagName('info1').data
does this work? (im not amazing at python just a quick thought)
name[0].firstChild.nodeValue

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