Non-serializable types passed to JSON writer causes failure to save table.

[mhangaard]

Overview

Table.save fails to export as JSON format if there are number types in the Table.schema.

To reproduce:

1. Use the CSV from this example and save as 'people.csv'
2. Add a .0 to make the "Age" type read as a float.
3. Then

table = Table('people.csv')
table.infer()
print(table.read(keyed=True))
table.save('people.json', format='json', keyed=True)

Output:

[{'Name': 'Jill', 'Email': 'jill@foo.com', 'Age': Decimal('25.0')}, {'Name': 'Jack', 'Email': 'jackbar.com', 'Age': Decimal('33.0')}]
---------------------------------------------------------------------------
TypeError                                 Traceback (most recent call last)
<ipython-input-242-01a5e53b8e4f> in <module>
      2 table.infer()
      3 print(table.read(keyed=True))
----> 4 table.save('people.json', format='json', keyed=True)

~/anaconda3/envs/qprops/lib/python3.7/site-packages/tableschema/table.py in save(self, target, storage, **options)
    423         if storage is None:
    424             with Stream(self.iter, headers=self.__schema.headers) as stream:
--> 425                 stream.save(target, **options)
    426             return True
    427 

~/anaconda3/envs/qprops/lib/python3.7/site-packages/tabulator/stream.py in save(self, target, format, encoding, **options)
    728         # Write data to target
    729         writer = writer_class(**writer_options)
--> 730         return writer.write(self.iter(), target, headers=self.headers, encoding=encoding)
    731 
    732     # Private

~/anaconda3/envs/qprops/lib/python3.7/site-packages/tabulator/writers/json.py in write(self, source, target, headers, encoding)
     37             count += 1
     38         with open(target, 'w') as file:
---> 39             json.dump(data, file, indent=2)
     40         return count

~/anaconda3/envs/qprops/lib/python3.7/json/__init__.py in dump(obj, fp, skipkeys, ensure_ascii, check_circular, allow_nan, cls, indent, separators, default, sort_keys, **kw)
    177     # could accelerate with writelines in some versions of Python, at
    178     # a debuggability cost
--> 179     for chunk in iterable:
    180         fp.write(chunk)
    181 

~/anaconda3/envs/qprops/lib/python3.7/json/encoder.py in _iterencode(o, _current_indent_level)
    427             yield _floatstr(o)
    428         elif isinstance(o, (list, tuple)):
--> 429             yield from _iterencode_list(o, _current_indent_level)
    430         elif isinstance(o, dict):
    431             yield from _iterencode_dict(o, _current_indent_level)

~/anaconda3/envs/qprops/lib/python3.7/json/encoder.py in _iterencode_list(lst, _current_indent_level)
    323                 else:
    324                     chunks = _iterencode(value, _current_indent_level)
--> 325                 yield from chunks
    326         if newline_indent is not None:
    327             _current_indent_level -= 1

~/anaconda3/envs/qprops/lib/python3.7/json/encoder.py in _iterencode_dict(dct, _current_indent_level)
    403                 else:
    404                     chunks = _iterencode(value, _current_indent_level)
--> 405                 yield from chunks
    406         if newline_indent is not None:
    407             _current_indent_level -= 1

~/anaconda3/envs/qprops/lib/python3.7/json/encoder.py in _iterencode(o, _current_indent_level)
    436                     raise ValueError("Circular reference detected")
    437                 markers[markerid] = o
--> 438             o = _default(o)
    439             yield from _iterencode(o, _current_indent_level)
    440             if markers is not None:

~/anaconda3/envs/qprops/lib/python3.7/json/encoder.py in default(self, o)
    177 
    178         """
--> 179         raise TypeError(f'Object of type {o.__class__.__name__} '
    180                         f'is not JSON serializable')
    181 

TypeError: Object of type Decimal is not JSON serializable

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Please preserve this line to notify @roll (lead of this repository)

[mhangaard]

Sorry this was the wrong repo. I opened the correct issue here: frictionlessdata/tableschema-py#288