Updated FolioClient to use dynamic properties for api token values

[bltravis]

Refactored login method to support login-with-expiry endpoint and additional RTR data. Implemented okapi_token and okapi_headers as dynamic properties that should always return a valid api token. Fixes Implement support for refresh tokens for FOLIO API keys (Poppy) #27

• Update login method to support /authn/login-with-expiry in addition to /authn/login
• Ensure that okapi_token and okapi_headers return a "fresh" api token when accessed
• Confirm backwards-compatibility with Orchid and earlier

[todolson]

I like the general approach. I've left three comments in the code.

[bltravis]

@todolson Can you give this another quick glance. I've pulled out the refresh token approach in favor of just logging in again (per recommendation here: https://wiki.folio.org/x/Lyq-BQ#RefreshTokenRotation(RTR)-Aguidefornon-moduleclientssuchasscriptsorotherintegrations). I've also implemented the okapi_headers attribute as a dynamic property that allows modification of all headers except x-okapi-token. This was done to support using the client in an enhanced consortial support (ECS) context, where the same client (and token) may be used to address multiple data tenants.

[todolson]

@bltravis , I've not used properties in earnest, and I'm a bit rusty in any case, so it took me a bit to get this. Have also confirmed in the REPL that this works. But it has the desired effect and I don't have any suggestions.
Also, I note that one can set the okapi_token property, which will update the x-okapi-token header. I believe is as intended.
No other comments.

[sonarcloud]

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[bltravis]

@bltravis … Also, I note that one can set the okapi_token property, which will update the x-okapi-token header. I believe is as intended. No other comments.

@todolson, Hmmm… 🤔 You're right. That really shouldn't be settable via the property. I've removed the setter and the deleter. self.okapi_token is now read-only, and the token is being set in self.login via self._okapi_token