Serialization error in Web API with numpy arrays

[bonjourmauko]

Hi there!

I really enjoy OpenFisca, but I recently encountered an issue.

Here is what I did:

I visited https://fr.openfisca.org/legislation

Here is what I expected to happen:

To work.

Here is what actually happened:

It didn't.

Here is data (or links to it) that can help you reproduce this issue:

If you have access to the server, try:

journalctl -u openfisca-web-api-fr-latest.service

TypeError: Object of type ndarray is not JSON serializable
During handling of the above exception, another exception occurred:
Traceback (most recent call last):
  File "/home/openfisca/virtualenvs/api-fr-latest/lib/python3.7/site-packages/gunicorn/workers/sync.py", line 135, in handle
    self.handle_request(listener, req, client, addr)
  File "/home/openfisca/virtualenvs/api-fr-latest/lib/python3.7/site-packages/gunicorn/workers/sync.py", line 176, in handle_request
    respiter = self.wsgi(environ, resp.start_response)
  File "/home/openfisca/virtualenvs/api-fr-latest/lib/python3.7/site-packages/flask/app.py", line 2463, in __call__
    return self.wsgi_app(environ, start_response)
  File "/home/openfisca/virtualenvs/api-fr-latest/lib/python3.7/site-packages/werkzeug/middleware/proxy_fix.py", line 228, in __call__
    return self.app(environ, start_response)
  File "/home/openfisca/virtualenvs/api-fr-latest/lib/python3.7/site-packages/flask/app.py", line 2449, in wsgi_app
    response = self.handle_exception(e)
  File "/home/openfisca/virtualenvs/api-fr-latest/lib/python3.7/site-packages/flask_cors/extension.py", line 161, in wrapped_function
    return cors_after_request(app.make_response(f(*args, **kwargs)))
  File "/home/openfisca/virtualenvs/api-fr-latest/lib/python3.7/site-packages/flask/app.py", line 1878, in handle_exception
    server_error = handler(server_error)
  File "/home/openfisca/virtualenvs/api-fr-latest/lib/python3.7/site-packages/openfisca_web_api/app.py", line 182, in internal_server_error
    message = str(e.args[0])

Otherwise, in your terminal:

git clone git@github.com:openfisca/openfisca-core.git
cd openfisca-core
make uninstall
make install
pip install openfisca-france ipython
ipython

Then try the following snippet:

from flask import Flask, jsonify
from openfisca_core.scripts import build_tax_benefit_system
from openfisca_web_api.loader import build_data

def trace():
    tax_benefit_system = build_tax_benefit_system("openfisca_france", None, None)
    data = build_data(tax_benefit_system)
    return data["openAPI_spec"]["definitions"]["Trace"]["example"]["trace"]

def acc(data, key):
    params = data[key]["parameters"]
    return [(key, param, params[param], type(params[param])) for param in params.keys()]

def serializable(value):
    try:
        jsonify({**value})
        return True
    except TypeError:
        return False

with Flask(__name__).app_context():
    data = trace()
    result = [acc(data, key) for key, _ in data.items() if not serializable(data[key])]

Expected

result
>>> []

Actual

result[0][0]
(
  'aide_logement_loyer_plafond<2017-12>',
  'prestations.aides_logement.loyers_plafond.par_zone<2017-12-01>',
  array([51.54]),
  numpy.ndarray),
  )

Context

I identify more as a:

• Developer (I create tools that use the existing OpenFisca code).