Work with PROV-XML

PROV-XML support needs the optional lxml dependency:

python -m pip install "prov[xml]"

Serialize to a file

import prov.model as pm

document = pm.ProvDocument()
document.set_default_namespace("http://example.org/")
document.entity("e1")

document.serialize("document.xml", format="xml")

Serialize to a string

xml_str = document.serialize(format="xml")
print(xml_str)

Force xsd:type attributes

By default xsi:type is only written for prov:type, prov:location, and prov:value, matching the PROV-XML spec examples. Pass force_types=True to write it for every non-prov: attribute too:

xml_str_typed = document.serialize(format="xml", force_types=True)

Deserialize from a file or stream

loaded = pm.ProvDocument.deserialize("document.xml", format="xml")
assert loaded == document

Deserialize from a string

loaded = pm.ProvDocument.deserialize(content=xml_str, format="xml")

Auto-detect the format with prov.read()

prov.read() tries PROV-JSON, then PROV-O/RDF, then PROV-N, then PROV-XML, stopping at the first deserializer that succeeds. In practice this means plain PROV-XML content almost never auto-detects: the RDF (TriG) parser is tried before the XML one, and on real PROV-XML input it fails with an rdflib syntax error rather than one of the exception types read() catches (TypeError, ValueError, AttributeError, KeyError) — so that error propagates before PROV-XML ever gets a turn:

import prov

try:
    prov.read("document.xml")  # no format given
except Exception as e:
    print(f"{type(e).__name__}: autodetect did not reach the XML deserializer")

loaded = prov.read("document.xml", format="xml")  # works
assert loaded == document

Always pass format="xml" explicitly when reading PROV-XML; do not rely on autodetection for this format.

Common errors

Malformed XML raises lxml’s own syntax error, not a prov-specific exception:

try:
    pm.ProvDocument.deserialize(content="not xml", format="xml")
except Exception as e:
    print(f"{type(e).__name__}: {e}")

XMLSyntaxError: Start tag expected, '<' not found, line 1, column 1 (<string>, line 1)