Work with PROV-JSON

PROV-JSON is the default format used by serialize()/deserialize(). It needs no extra dependency — the serializer is always available.

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.json")  # format="json" is the default

Serialize to a string

Omit destination (or pass None) to get the serialization back as a string:

json_str = document.serialize()
print(json_str)

Deserialize from a file or stream

loaded = pm.ProvDocument.deserialize("document.json")
assert loaded == document

source also accepts an open stream:

with open("document.json") as f:
    loaded = pm.ProvDocument.deserialize(f)

Deserialize from a string

Use the content keyword instead of source:

loaded = pm.ProvDocument.deserialize(content=json_str, format="json")

Auto-detect the format with prov.read()

prov.read() tries every registered deserializer in turn — PROV-JSON, then PROV-O/RDF, then PROV-N, then PROV-XML — until one succeeds, so it works without knowing the format up front. PROV-JSON is tried first, so valid PROV-JSON content always auto-detects correctly:

import prov

loaded = prov.read("document.json")
assert loaded == document

Passing format="json" explicitly skips the trial-and-error and gives a proper traceback if the content is not valid JSON.

Common errors

Malformed JSON raises the standard library’s decoder error, not a prov-specific exception:

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

JSONDecodeError: Expecting value: line 1 column 1 (char 0)

Calling prov.read() without format on content that matches none of the registered formats only raises the documented fallback TypeError (“Could not read from the source…”) if every deserializer it tries fails with one of TypeError, ValueError, AttributeError, or KeyError — those are the only exceptions read() catches while it tries formats in turn. In practice the RDF deserializer (tried before PROV-XML) usually raises an rdflib parser error first, which is not in that list, so it propagates immediately instead. Either way: pass format= explicitly if you want a predictable, format-specific error.