Use Protocol interfaces and static duck typing design pattern

[francbartoli]

Is your feature request related to a problem? Please describe.
In order to improve flexibility and composability over inheritance it would be beneficial to improve the design using static duck typing PEP 544

Describe the solution you'd like
This is a very basic example how we can use it to adopt standard dataclasses as replacement of pydantic data models but at the same type leave the flexibility to use them for data validation in a fancy way without touching the core:

from typing import Any, Protocol

from pydantic import RootModel
from pydantic.dataclasses import dataclass as p_dataclass
from dataclasses import dataclass

from pygeoapi.models.openapi import SupportedFormats


class OAPIFormat(Protocol):
    """Interface for OpenAPI Format"""

    root: SupportedFormats


class OAPIPydantic(RootModel):
    root: SupportedFormats = SupportedFormats.YAML.value


@dataclass
class OAPI(OAPIFormat):
    """OpenAPI definition"""

    root:SupportedFormats


@p_dataclass
class OAPI_PydanticDataclass(OAPIFormat):
    """OpenAPI definition"""
    root:SupportedFormats


def check_openapi_format(format: OAPIFormat):
    """Check OpenAPI Format"""
    print(format)

Describe alternatives you've considered
A clear and concise description of any alternative solutions or features you've considered.

Additional context
Add any other context or screenshots about the feature request here.

[github-actions]

This Issue has been inactive for 90 days. As per RFC4, in order to manage maintenance burden, it will be automatically closed in 7 days.

[vvmruder]

I would be interested to see the move to plain dataclasses as well. Since they are part of python this should be more stable than using pydantic. Currently I'm facing the same problem as described here #1664

Is there a roadmap when this could happen? I could support working on that.

[francbartoli]

@ricardogsilva can you please share the WIP that you developed during the sprint?

[github-actions]

This Issue has been inactive for 90 days. As per RFC4, in order to manage maintenance burden, it will be automatically closed in 7 days.

[francbartoli]

@vvmruder Sorry for the late reply, the roadmap that we agreed during the sprint last year was to:

• Adopt the use of Protocol interfaces and support the static typing design pattern
• Implement the interfaces with the standard dataclasses in the core so that we can get rid of the pydantic dependency
• Remove pydantic from the core but at the same time support a pydantic plugin to override the serialisation (and validation) of the responses

@ricardogsilva had developed a very early implementation of the above but I'm not sure he has already that available from his fork

[vvmruder]

@francbartoli I really appriceate this decision and looking forward to use it.

Again, I can offer a hand to support the work on that. Please get in touch.