How to parse a user-uploaded XML file in Python Dash?

Dash Python
1

New to Python and Dash, so sorry if this is a simple question.
Looked online but could not find any answers.

I have a dcc.Upload object with an html.Button, where users can upload an XML file.
Then, using a callback function, I would like to parse this file and return some simple data from the XML.
In regular python I would do this with

tree = et.parse("file.xml")
root = tree.getroot()
...
for node in root:
    title = node.find("series_title").....

but this does not seem to work in Dash/HTML.
Any idea how I would go about parsing files uploaded on Dash?
I think it has something to with the ‘contents’ data created when uploading a file, but a bit lost.

Any help is appreciated, thank you!

2

Figured it out, and will leave this here in case others come across the same issue.

Looks like the ‘contents’ of the file is read in as ‘content_string’ in base64.
Decode it first, then set up a tree, which you can then get the nodes in each root from.

content_type, content_string = contents.split(',')
    # content_string is in base64, so decode it
    decoded = base64.b64decode(content_string)
    tree = et.ElementTree(et.fromstring(decoded))

    root = tree.getroot()
    for node in root:....
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