How to send a custom response by overriding the API Interface

Let's take an example of sending a custom response for the /auth/signup/email/exists GET API (does email exist).

We need to first override the function for that API (emailExistsGET) and then use the response object in the input param to send a custom response.

The function signature expects an return type that has a certain shape, therefore, we must still return a valid response object from the function, but that will be ignored since you have already sent a response to the client.

NodeJS
GoLang
Python

import Passwordless from "supertokens-node/recipe/passwordless";

Passwordless.init({

    override: {
        apis: (originalImplementation) => {
            return {
                ...originalImplementation,
                emailExistsGET: async function (input) {

                    // we can send a custom response like this:
                    input.options.res.setStatusCode(200); // or any other status code
                    input.options.res.sendJSONResponse({
                        message: "my custom response",
                        //...
                    })

                    // this return doesn't matter. But we must do it
                    // cause the function signature expects a response.
                    return {
                        status: "OK",
                        exists: false
                    };
                }
            }
        }
    }
})

import (
    "encoding/json"

    "github.com/supertokens/supertokens-golang/recipe/passwordless/plessmodels"
    "github.com/supertokens/supertokens-golang/recipe/passwordless"
    "github.com/supertokens/supertokens-golang/supertokens"
)

func main() {
    passwordless.Init(plessmodels.TypeInput{
        Override: &plessmodels.OverrideStruct{
            APIs: func(originalImplementation plessmodels.APIInterface) plessmodels.APIInterface {

                (*originalImplementation.EmailExistsGET) = func(email string, options plessmodels.APIOptions, userContext supertokens.UserContext) (plessmodels.EmailExistsGETResponse, error) {

                    // we create our custom response.
                    options.Res.Header().Set("Content-Type", "application/json; charset=utf-8")
                    options.Res.WriteHeader(200)
                    responseJson := map[string]interface{}{
                        "message": "My custom response",
                        // ...
                    }

                    bytes, _ := json.Marshal(responseJson)
                    options.Res.Write(bytes)

                    // this return doesn't matter. But we must do it
                    // cause the function signature expects a response.
                    return plessmodels.EmailExistsGETResponse{
                        OK: &struct{ Exists bool }{
                            Exists: false,
                        },
                    }, nil
                }

                return originalImplementation
            },
        },
    })
}

from supertokens_python.recipe import passwordless
from supertokens_python.recipe.passwordless.interfaces import APIOptions, EmailExistsGetOkResult
from typing import Dict, Any
from supertokens_python.recipe.passwordless.interfaces import APIInterface


def override_passwordless_apis(original_implementation: APIInterface):

    async def email_exists_get(email: str, api_options: APIOptions, user_context: Dict[str, Any]):

        # send custom response like this
        api_options.response.set_status_code(200)  # or any other status code
        json_dict = {'message': 'Custom response'}
        api_options.response.set_json_content(json_dict)

        # this return doesn't matter. But we must do it
        # cause the function signature expects a response.
        return EmailExistsGetOkResult(False)

    original_implementation.email_exists_get = email_exists_get
    return original_implementation

passwordless.init(
    override=passwordless.InputOverrideConfig(
        apis=override_passwordless_apis
    )
)