Openfisca-core

_Note: this version has been unpublished due to an issue introduced by 23.4.0 in the Web API. Please use 23.5.2 or a more recent version._

* Fix API source IP detection through proxies.

_Note: this version has been unpublished as it introduced an issue in the Web API. Please use 23.5.2 or a more recent version._

* Use `/` rather than `.` in the path to access a parameter:
- For instance `/parameter/benefits.basic_income` becomes `/parameter/benefits/basic_income`
- Using `.` is for now still supported, but is considered deprecated and will be turned to a 301 redirection in the next major version.

* Expose parameters `metadata` and `source` in the Web API and:

For instance, `/parameter/benefits/basic_income` contains:

JSON
{
"description": "Amount of the basic income",
"id": "benefits.basic_income",
"metadata": {
"reference": "https://law.gov.example/basic-income/amount",
"unit": "currency-EUR"
},
"source": "https://github.com/openfisca/country-template/blob/3.2.2/openfisca_country_template/parameters/benefits/basic_income.yaml",
"values": {
"2015-12-01": 600.0
}
}


* Expose parameters nodes in the Web API
- For instance, `/parameter/benefits` now exists and contains:

JSON
{
"description": "Social benefits",
"id": "benefits",
"metadata": {},
"source": "https://github.com/openfisca/country-template/blob/3.2.2/openfisca_country_template/parameters/benefits",
"subparams": {
"basic_income": {
"description": "Amount of the basic income"
},
"housing_allowance": {
"description": "Housing allowance amount (as a fraction of the rent)"
}
}
}


Note that this route doesn't _recursively_ explore the node, and only exposes its direct children name and description.

Minor Change without any impact for country package developers and users:
- Make code more Python3-like by backporting unicode literals.
- With this backport, all strings are by default unicodes.
- The `u` prefix for strings should *not* be used anymore.
- Each new module must start by `from __future__ import unicode_literals` for the backport to be effective.

* Send reference of the country-package and its version to the tracker so it will appear in the tracking statistics.

* Change the way metadata are declared for Parameter.

Before:
YAML
description: Age of retirement
reference: https://wikipedia.org/wiki/retirement
unit: year
values: (...)


After:
YAML
description: Age of retirement
metadata:
reference: https://wikipedia.org/wiki/retirement
unit: year
values: (...)


_Setting `unit` and `reference` out of `metadata` is considered deprecated, but still works for backward compatibility._

* Allow legislation coders to define their own medatada

* Expose in the Python API
- Parameters metadata:
- e.g. `parameters.taxes.rate.metadata['unit']`
- Parameter value metadata:
- e.g. `parameters.taxes.rate.values_list[0].metadata['unit']`
- Parameter node description and metadata:
- e.g. `parameters.taxes.metadata['reference']`, `parameters.taxes.description`
- Note: Parameter descriptions (e.g. `parameters.taxes.rate.description`) were already exposed

* Introduce `TaxBenefitSystem.replace_variable`
- Unlike `update_variable`, this method does _not_ keep any of the replaced variable in the new one.
- See [reference documentation](https://openfisca.org/doc/openfisca-python-api/tax-benefit-system.html#openfisca_core.taxbenefitsystems.TaxBenefitSystem.replace_variable).