Python 3 jsonify on b64encode(asset_report_pdf) throws TypeError exception

[gregbehm]

The server.py Asset Report code attempts to jsonify the base-64-encoded PDF report:

return jsonify({
    'error': None,
    'json': asset_report_json,
    'pdf': base64.b64encode(asset_report_pdf),
  })

For Python 3, this throws a TypeError exception:

[2019-04-24 15:10:09,368] ERROR in app: Exception on /assets [GET]
Traceback (most recent call last):
  File "/Users/gbehm/miniconda3/envs/plaid37/lib/python3.7/site-packages/flask/app.py", line 2292, in wsgi_app
    response = self.full_dispatch_request()
  File "/Users/gbehm/miniconda3/envs/plaid37/lib/python3.7/site-packages/flask/app.py", line 1815, in full_dispatch_request
    rv = self.handle_user_exception(e)
  File "/Users/gbehm/miniconda3/envs/plaid37/lib/python3.7/site-packages/flask/app.py", line 1718, in handle_user_exception
    reraise(exc_type, exc_value, tb)
  File "/Users/gbehm/miniconda3/envs/plaid37/lib/python3.7/site-packages/flask/_compat.py", line 35, in reraise
    raise value
  File "/Users/gbehm/miniconda3/envs/plaid37/lib/python3.7/site-packages/flask/app.py", line 1813, in full_dispatch_request
    rv = self.dispatch_request()
  File "/Users/gbehm/miniconda3/envs/plaid37/lib/python3.7/site-packages/flask/app.py", line 1799, in dispatch_request
    return self.view_functions[rule.endpoint](**req.view_args)
  File "server.py", line 158, in get_assets
    'pdf': base64.b64encode(asset_report_pdf),
  File "/Users/gbehm/miniconda3/envs/plaid37/lib/python3.7/site-packages/flask/json/__init__.py", line 321, in jsonify
    dumps(data, indent=indent, separators=separators) + '\n',
  File "/Users/gbehm/miniconda3/envs/plaid37/lib/python3.7/site-packages/flask/json/__init__.py", line 179, in dumps
    rv = _json.dumps(obj, **kwargs)
  File "/Users/gbehm/miniconda3/envs/plaid37/lib/python3.7/json/__init__.py", line 238, in dumps
    **kw).encode(obj)
  File "/Users/gbehm/miniconda3/envs/plaid37/lib/python3.7/json/encoder.py", line 199, in encode
    chunks = self.iterencode(o, _one_shot=True)
  File "/Users/gbehm/miniconda3/envs/plaid37/lib/python3.7/json/encoder.py", line 257, in iterencode
    return _iterencode(o, 0)
  File "/Users/gbehm/miniconda3/envs/plaid37/lib/python3.7/site-packages/flask/json/__init__.py", line 81, in default
    return _json.JSONEncoder.default(self, o)
  File "/Users/gbehm/miniconda3/envs/plaid37/lib/python3.7/json/encoder.py", line 179, in default
    raise TypeError(f'Object of type {o.__class__.__name__} '
TypeError: Object of type bytes is not JSON serializable

In Python 3, base64.b64encode(asset_report_pdf) accepts a bytes-like object and returns encoded bytes. The interface changed from Python 2.7, where base64.b64encode(asset_report_pdf) accepts a str and returns an encoded str.

For Python 3, the output of base64.b64encode(asset_report_pdf) should be converted to str before attempting to jsonify.

[gregbehm]

I'm planning to open a PR for a fix.

[davidzhanghp]

thank you for opening the pr @gregbehm