Keep response body object as dict instead converting to string from event handler

[radder5]

using the examples from https://docs.powertools.aws.dev/lambda/python/latest/core/event_handler/api_gateway/#lambda-function-url for a dict return value from a route, I'd like to keep that as a nested object within the body property but this always gets serialized to a JSON string.
e.g.
@app.get("/timings/<year>/<month>") def get_timings_by_month_year(year: Annotated[int, Path(ge=2023,le=datetime.now().year)], month: Annotated[int, Path(le=12, ge=1)]) -> dict: return {"timings": "some timings"}

returns

{ "statusCode": 200, "body": "{\"timings\":\"some timings\"}", "isBase64Encoded": false, "headers": { "Content-Type": "application/json" }, "cookies": [] }

I would like it to return

{ "statusCode": 200, "body": { "timings": "some timings" }, "isBase64Encoded": false, "headers": { "Content-Type": "application/json" }, "cookies": [] }

is this possible?
Thanks

[kattakaha]

Hi! @radder5

Even if you simply want to respond with {"timings": "some timings"}, (<- This type is Python dict) this needs to be a string to pass through the API Gateway, whether it is encoded or not. Therefore, there is a need to cast the response body to a string in some way.

For example, you can forcibly cast it to a string like this, but I think it's difficult to use it in a general way.

@app.get("/hello")
def hello() -> str:
    return '{"message": "Hello, world!"}' # string

Therefore, I believe the focus of the problem should be adjusted to parsing the JSON on the client side rather than on the server side.

For example, if you are using Node.js, you can use fetch to convert the response to JSON like this:

const fetch = require('node-fetch');

async function getTimings() {
    const response = await fetch('http://your-api-endpoint');
    const data = await response.json();
    console.log(data);
}

getTimings();

Finally, this is another option, "customizing the integration response in API Gateway" is also a possible solution.