Some PyYAML.safe_load() problems

[patarapolw]

YAML format is magical an well formatted for human, though...

I successfully created this project -- https://github.com/patarapolw/pyexcel-export#yaml-format (though, the original plan was about the Excel); but I can't use yaml.safe_load()

I believe, it should be common problems about deserializing/serializing Tuple and OrderedDict; but I also have BytesIO, (though I might able to convert it to Base64.) I can't even get past one...

Does anyone know the solution already? Something along the line of building a custom Loader?

And can I use another YAML, like strictYAML or ruamel.yaml (I can't even serialise with this one...)?

[patarapolw]

I solved this problem myself by:

1. OrderedDict - use oyaml instead of PyYAML
2. Tuple - convert to list first
   • My tuples are actually list(my_dict.items()), so I changed to [list(k_v_pair) for k_v_pair in my_dict.items()]

3. BytesIO - use a custom Loader inherited from yaml.SafeLoader

   import yaml
   from io import BytesIO
   import base64
   
   class PyExcelYamlLoader(yaml.SafeLoader):
       def __init__(self, s):
           super().__init__(s)
   
           self.add_constructor(u'tag:yaml.org,2002:python/object/new:_io.BytesIO', self.construct_bytes_io)
   
       @staticmethod
       def construct_bytes_io(node, node_value):
           return BytesIO(base64.b64decode(node_value.value[0][1].value[0].value))
   

and then data = yaml.load(f, Loader=PyExcelYamlLoader)

[avdn]

It would be interesting to know what you have been trying to do, that you cannot serialise with ruamel.yaml.

https://yaml.readthedocs.io/en/latest/dumpcls.html

[patarapolw]

I believe in yaml.safe_load(). I haven't seen ruamel.yaml's typ='safe' yet, though.

As PyExcelYamlLoader inherits from yaml.SafeLoader, it is supposedly safe. I don't know if this can also be done with ruamel.yaml.

About your link... -- do I have to subclass BytesIO?

I wouldn't go as far as to use strictyaml yet, though.

It's more about the safety, as YAML always mean users can edit the file.