def read(source, format=None):
"""
Convenience function returning a ProvDocument instance.
It does a lazy format detection by simply using try/except for all known
formats. The deserializers should fail fairly early when data of the
wrong type is passed to them thus the try/except is likely cheap. One
could of course also do some more advanced format auto-detection but I am
not sure that is necessary.
The downside is that no proper error messages will be produced, use the
format parameter to get the actual traceback.
"""
# Lazy imports to not globber the namespace.
from prov.model import ProvDocument
from prov.serializers import Registry
Registry.load_serializers()
serializers = Registry.serializers.keys()
if format:
return ProvDocument.deserialize(source=source, format=format.lower())
for format in serializers:
try:
return ProvDocument.deserialize(source=source, format=format)
except:
pass
else:
raise TypeError("Could not read from the source. To get a proper "
"error message, specify the format with the 'format' "
"parameter.")
def test_reading_and_writing_to_file_like_objects(self):
"""
Tests reading and writing to and from file like objects.
"""
# Create some random document.
document = ProvDocument()
document.entity(EX2_NS["test"])
objects = [io.BytesIO, io.StringIO]
Registry.load_serializers()
formats = Registry.serializers.keys()
for obj in objects:
for format in formats:
try:
buf = obj()
document.serialize(destination=buf, format=format)
buf.seek(0, 0)
new_document = ProvDocument.deserialize(source=buf,
format=format)
self.assertEqual(document, new_document)
except NotImplementedError:
# Some serializers might not implement serialize or deserialize method
pass # and this is fine in the context of this test
finally:
buf.close()
def provRead(source, format=None):
from prov.model import ProvDocument
from prov.serializers import Registry
Registry.load_serializers()
serializers = Registry.serializers.keys()
if format:
try:
ret = ProvDocument.deserialize(source=source,
format=format.lower())
return ret
except Exception as e:
log.error(e)
raise TypeError(e)
for format in serializers:
source.seek(0)
try:
return ProvDocument.deserialize(source=source, format=format)
except:
pass
else:
raise TypeError("Could not read from the source. To get a proper "
"error message, specify the format with the 'format' "
"parameter.")
def test_reading_and_writing_to_file_like_objects(self):
"""
Tests reading and writing to and from file like objects.
"""
# Create some random document.
document = ProvDocument()
document.entity(EX2_NS["test"])
objects = [io.BytesIO, io.StringIO]
Registry.load_serializers()
formats = Registry.serializers.keys()
for obj in objects:
for format in formats:
try:
buf = obj()
document.serialize(destination=buf, format=format)
buf.seek(0, 0)
new_document = ProvDocument.deserialize(source=buf,
format=format)
self.assertEqual(document, new_document)
except NotImplementedError:
# Some serializers might not implement serialize or
# deserialize method
pass # and this is fine in the context of this test
finally:
buf.close()