kwatsen
commented
5 years ago One issue that may be encountered while trying to address this issue is which of the several available Python modules from XML to use.
Of course, when the Yangson API is importing/exporting a string containing YANG-compliant XML, this isn't an issue, as Yangson can do internally whatever it needs to do.
The issue is more for when the Yangson API is importing/exporting raw values. This is an issue only because no Python module for XML seems to work seems to give the expected result. Some modules looked at include:
For instance, the JSON:
{
"my-module:input" : {
"foobar" : [null]
}
}becomes (with the standard json module):
{
'my-module:input': {
'foobar': [None]
}
}Whereas the XML:
<input xmlns="https://example.com/my-module">
<foobar/>
</input>becomes (with xmltodict and some parameters to map namespaces into prefixes):
OrderedDict([
(
'my-module:input',
OrderedDict([
(
'my-module:foobar', None
)
])
)
])which, when loaded into Yangson, using SchemeNode.from_raw(), produces the following error:
sn.from_raw(req_input)
File "/Users/kent/.pyenv/versions/3.7.3/lib/python3.7/site-packages/yangson/schemanode.py", line 446, in from_raw
res[ch.iname()] = ch.from_raw(rval[qn], npath)
File "/Users/kent/.pyenv/versions/3.7.3/lib/python3.7/site-packages/yangson/schemanode.py", line 834, in from_raw
raise RawTypeError(jptr, self.type.yang_type() + " value")
yangson.exceptions.RawTypeError: [/my-module:foobar] expected empty valueResults from lxml.objectify and untangle produce results that are even further from pure Python structures (i.e., without use of special module-specific classes).
This makes me wonder if if might not be possible to "simple" YANG-based XML to/from pure Python structure that, by nature of being solely for YANG-modeled objects, can do the right thing...
That said, the easiest/best approach should come from a convertor that is schema-driven, but then this is exactly where Yangson can fit it. For instance, SchemaNode.obj_to_xml(python_object) -> xml_string and `SchemaNode.xml_to_obj(xml_string) -> python_object.
Actually, it seems that, if these two methods were provided, then this issue could be closed, as these methods could be use in conjunction with the existing to_raw and from_raw methods for functional albeit less efficient XML support, which might be a sweet spot.
llhotka
HRogge
As discussed at the 103 social, it would would be excellent to also support XML-encoded instance data.
My project uses supports both XML and JSON. I imagine many projects are this way...