About Invoices

[cirotix]

I see from the git history (and from the forks of this project) that there is some confusion about the Invoices stream.

from streams.py

class Invoices(Stream):
    name = "invoices"
    replication_method = "INCREMENTAL"
    # replication_key = "updated_at"
    replication_key = "due_date"
    # API endpoint filters only on `due_date`.

We can see that the replication key has due_date and had been updated_at. There was a back and forth on this line in the commits.
The fact is there are actually two very different Invoice objects in Chargify:

• Legacy invoices (instances prior to Jan 2018)
  https://reference.chargify.com/v1/invoices-legacy/invoices
• Relationship Invoices (instances after Jan 2018)
  https://reference.chargify.com/v1/relationship-invoicing/relationship-invoicing-intro

Legacy Invoices have a updated_at property
Relationship Invoices have a due_date property
Both of them have a completely different structure and are unrelated. The most confusing part is that they have the same endpoint in Chargify API: /invoices/
You'll get one or the other depending on the instance you have.

I will open a PR to fix this issue. Unfortunately, I only have instances with Legacy Invoices so I can only test this. But I will provide a scafolder for the new Relationship Invoices.