GET APIRequest attributes and converters

[vincentsarago]

in #729 and #714 we've tried using dataclass and attrs to define the APIRequest class used as GET Request model (defining QueryParameters)

With #729 we've moved back to attrs and successfully were able to use alias field (like filter-crs, #638)

While this work great, I've discovered that it won't work when an attribute will have a converter:

from typing import Optional
from typing_extensions import Annotated

from stac_fastapi.types.search import APIRequest
import attr

from fastapi import Query


@attr.s
class GetRequest(APIRequest):
    filter_crs: Annotated[
        Optional[int], 
        Query(alias="filter-crs")
    ] = attr.ib(default=None)

GetRequest?

    Init signature:
    GetRequest(
        filter_crs: Annotated[Optional[int], Query(PydanticUndefined)] = None,
    ) -> None
    Docstring:      Generic API Request base class.
    Init docstring: Method generated by attrs for class GetRequest.
    Type:           type
    Subclasses:     



@attr.s
class BadGetRequest(APIRequest):
    filter_crs: Annotated[
        Optional[int], 
        Query(alias="filter-crs")
    ] = attr.ib(default=None, converter=int)

BadGetRequest?

    Init signature: BadGetRequest(filter_crs=None) -> None
    Docstring:      Generic API Request base class.
    Init docstring: Method generated by attrs for class BadGetRequest.
    Type:           type
    Subclasses:     

from the attrs documentation

If a converter’s first argument has a type annotation, that type will appear in the signature for init. A converter will override an explicit type annotation or type argument.

This is also unfortunate because it disable adding openAPI documentation on attributes 😭

from typing import Optional
from typing_extensions import Annotated

from stac_fastapi.types.search import APIRequest, str2list
import attr

from fastapi import Query

@attr.s
class BaseSearchGetRequest(APIRequest):
    """Base arguments for GET Request."""

    collections: Annotated[
        Optional[str],
        Query(
            description="Array of collection Ids to search for items.",
            json_extra_schema={
                "examples":[
                    "collection1,collection2",
                ]
            }
        ),
    ] = attr.ib(
        default=None, converter=str2list
    )

BaseSearchGetRequest?

    Init signature: BaseSearchGetRequest(collections: str = None) -> None
    Docstring:      Base arguments for GET Request.
    Init docstring: Method generated by attrs for class BaseSearchGetRequest.
    Type:           type
    Subclasses:     
    Init signature:


@attr.s
class BaseSearchGetRequest(APIRequest):
    """Base arguments for GET Request."""

    collections: Annotated[
        Optional[str],
        Query(
            description="Array of collection Ids to search for items.",
            json_extra_schema={
                "examples":[
                    "collection1,collection2",
                ]
            }
        ),
    ] = attr.ib(
        default=None
    )

BaseSearchGetRequest?

    Init signature:
    BaseSearchGetRequest(
        collections: Annotated[Optional[str], Query(PydanticUndefined)] = None,
    ) -> None
    Docstring:      Base arguments for GET Request.
    Init docstring: Method generated by attrs for class BaseSearchGetRequest.
    Type:           type
    Subclasses:     

[vincentsarago]

Solution

add type annotation in the converter

def collection_converter(
    x: Annotated[
        Optional[str],
        Query(
            description="Array of collection Ids to search for items.",
            json_extra_schema={
                "examples":[
                    "collection1,collection2",
                ]
            }
        ),
    ]
) -> Optional[List]:
    """Convert string to list base on , delimiter."""
    if x:
        return x.split(",")