POST with Form parameter that is a list

[bdellegrazie]

Hi,

I'm trying to parse a POST based Form that has a multi-valued string property.
However this doesn't appear to work, is this a bug or incorrect syntax on my part? I'm not that familiar with Pydantic so any pointers appreciated. It does work for the string parameter, but not for the list.

Minimal (untested) example:

from typing import Annotated
from aws_lambda_powertools.event_handler import APIGatewayHttpResolver
from aws_lambda_powertools.event_handler.openapi.params import Form
from aws_lambda_powertools.utilities.typing import LambdaContext

app = APIGatewayHttpResolver(
    enable_validation=True,
)

@app.post("/example")
def example(
    param: Annotated[
        str,
        Form(),
    ],
    param_list: Annotated[
        list[str],
        Form(),
    ] = []
):
     pass

def lambda_handler(event: dict, context: LambdaContext) -> dict:
    return app.resolve(event, context)

I'm testing it by generating a dummy event to the lambda with body content like this:

import urlparse.parse

def test_example():
    # Also tested with tuple form [("param_list", ["value1", "value2"])]
    body  = urlparse.parse.urlencode({
        "param": "value",
        "param_list": ["value1", "value2"]
    }, doSeq=True)
    event = {
        "headers": [
            "accept": "application/json",
            "content-type": "application/x-www-form-urlencoded"
        ],
        ...
        "body": body 
    }
   ... rest of test elided

But I always get response code of 422 like this:

{
  "statusCode": 422,
  "detail": [
    {
      "loc": [
        "body","param_list"
      ],
      "type": "list_type"
    }
  ]
}

Any help / advice appreciated.
Thanks!

[leandrodamascena]

Hi @bdellegrazie I think this is a bug indeed when supporting Form() fields with list. Can you please open an issue with this and then I can fix it?
Thanks

[bdellegrazie]

Hi @leandrodamascena,

I've raised #7342 as requested
Thank you so much for your help!

[leandrodamascena]

Thanks @bdellegrazie! I'm closing this.