Save indicator as GeoJSON Feature to DB

[matthiasschaub]

Description

Extend database schema with one additional attribute of type JSON.
During saving indicator attribute to database, dump the
indicator.as_feature() output to the database as well. The reason is to
not lose any data when saving and loading and indicator from and to the
database such as the indicator.data attribute (see issue #145).

Workflow to save and load an indicator form the database will stay the same.
This work will be helpful in solving issue #145.

Checklist

• I have updated my branch to main (e.g. through git rebase main)
• My code follows the style guide and was checked with pre-commit before committing
• I have commented my code
• I have added sufficient unit and integration tests
• I have updated the CHANGELOG.md

[joker234]

If you run the tests, you're getting this error:

TypeError: Object of type datetime is not JSON serializable

This means that the JSON library is not capable of serializing datetime objects as part of a JSON. I would suggest to either represent the datetime objects beforehand in another date format (e.g. unix timestamp) or use a default serializer (e.g. str). Since you're not doing the serializing by yourself, I would suggest to find any representation and follow the first suggestion.

I made a suggestion, how you could fix it. You're free to use this and merge the other branch in yours or find something else: db-save-results-as-geojson...db-save-results-as-geojson-proposed-fix

ToDo: add proper tests (see your checklist)

[matthiasschaub]

Great catch! Thank you for looking into that.

We had this problem in the CLI module as well and have a solution already in place.

# helper.py
def datetime_to_isostring_timestamp(time: datetime) -> str:
    """
    Checks for datetime objects and converts them to ISO 8601 format.

    Serves as function that gets called for objects that can’t otherwise be
    serialized by the `json` module.
    It should return a JSON encodable version of the object or raise a TypeError.
    https://docs.python.org/3/library/json.html#basic-usage
    """
    try:
        return time.isoformat()
    except AttributeError:
        raise TypeError

I pushed a fixed version.