Set ISO date by parsing/converting free-form Expression publication date

[koeaw]

Use dateparser library to update non-editable date field publication_date_iso whenever free-form publication_date field is changed:

• override __init__ method for Expression entity to preserve current publication_date in variable
• override save method – including when update_fields=... option is set to relevant fields – to parse/set the ISO date

Allowed date formats are set via Django's DATE_INPUT_FORMATS variable.

[koeaw]

@b1rger Could I ask you to look this over? Does this implementation make sense or is there a better way to do this?

As said elsewhere, we'll have two fields for storing dates:

• one meant to be filled in by content creators, which isn't an actual date field but a char field; this is also where incoming dates from Zotero will be saved (... which are strings which don't have to follow any particular formatting),
• a proper DateField for the same piece of data, converted to ISO, so we'll be able to query/sort by date later on etc.

In our import scripts, we get_or_create entities, and my understanding is that using the save() method to do the conversion should cover both that and manual inputs via forms.

[b1rger]

did not test it, but lgtm!

[koeaw]

did not test it, but lgtm!

Thank you!