Custom error response using `GENERAL_ERROR` status

Sometimes, you may want to send a custom error message from your API override to display to the user on the frontend. This can be done by sending the following JSON response from the API:

{
    "status": "GENERAL_ERROR",
    "message": "Some custom error message"
}

If you are using our pre-built ReactJS UI, the above response will render the mesage "Some custom error message" on the frontend UI. For custom UI, you can read this response and display the message in an error UI. This response can be returned from most of the APIs exposed by the backend SDK.

Let's take an example in which we want to prevent the user from signing up unless their email is preapproved by the app's admin. For this, we will override the sign up API to check if the input email is approved or not, and if not, we prevent the sign up, and send a custom error message.

NodeJS
GoLang
Python

import ThirdParty from "supertokens-node/recipe/thirdparty";

ThirdParty.init({
    signInAndUpFeature: {
        providers: [/* ... */]
    },
    override: {
        functions: (oI) => {
            return {
                ...oI,
                signInUp: async function (input) {
                    if (emailNotAllowed(input.email)) {
                        // this error will signal to the API to send a GENERAL_ERROR message
                        throw new Error("Email not allowed");
                    }
                    return oI.signInUp(input);
                }
            }
        },
        apis: (oI) => {
            return {
                ...oI,
                signInUpPOST: async function (input) {
                    try {
                        return oI.signInUpPOST!(input);
                    } catch (err: any) {
                        if (err.message === "Email not allowed") {
                            return {
                                status: "GENERAL_ERROR",
                                message: "You are not allowed to sign up. Please contact the app's admin to get permission"
                            }
                        }
                        throw err;
                    }
                }
            }
        }
    }
})

function emailNotAllowed(email: string) {
    // TODO: your impl to check if email is allowed or not
    return true;
}

import (
    "errors"

    "github.com/supertokens/supertokens-golang/recipe/thirdparty"
    "github.com/supertokens/supertokens-golang/recipe/thirdparty/tpmodels"
    "github.com/supertokens/supertokens-golang/supertokens"
)

func main() {
    thirdparty.Init(&tpmodels.TypeInput{
        Override: &tpmodels.OverrideStruct{
            Functions: func(originalImplementation tpmodels.RecipeInterface) tpmodels.RecipeInterface {
                ogSignInUp := *originalImplementation.SignInUp

                (*originalImplementation.SignInUp) = func(thirdPartyID, thirdPartyUserID string, email string, userContext supertokens.UserContext) (tpmodels.SignInUpResponse, error) {
                    if emailNotAllowed(email) {
                        // this error will signal to the API to send a GENERAL_ERROR message
                        return tpmodels.SignInUpResponse{}, errors.New("Email not allowed")
                    }
                    return ogSignInUp(thirdPartyID, thirdPartyUserID, email, userContext)
                }
                return originalImplementation
            },
            APIs: func(originalImplementation tpmodels.APIInterface) tpmodels.APIInterface {
                ogSignInUpPOST := *originalImplementation.SignInUpPOST
                (*originalImplementation.SignInUpPOST) = func(provider tpmodels.TypeProvider, code string, authCodeResponse interface{}, redirectURI string, options tpmodels.APIOptions, userContext supertokens.UserContext) (tpmodels.SignInUpPOSTResponse, error) {
                    resp, err := ogSignInUpPOST(provider, code, authCodeResponse, redirectURI, options, userContext)
                    if err != nil {
                        if err.Error() == "Email not allowed" {
                            return tpmodels.SignInUpPOSTResponse{
                                GeneralError: &supertokens.GeneralErrorResponse{
                                    Message: "You are not allowed to sign up. Please contact the app's admin to get permission",
                                },
                            }, nil
                        }
                        return tpmodels.SignInUpPOSTResponse{}, err
                    }
                    return resp, err
                }
                return originalImplementation
            },
        },
    })
}

func emailNotAllowed(email string) bool {
    // TODO: your impl to check email
    return true
}

from supertokens_python.recipe import thirdparty
from supertokens_python.recipe.thirdparty.interfaces import APIInterface, RecipeInterface, APIOptions, SignInUpPostOkResult, SignInUpPostNoEmailGivenByProviderResponse, SignInUpOkResult
from supertokens_python.recipe.thirdparty.provider import Provider
from typing import Any, Dict, Union
from supertokens_python.types import GeneralErrorResponse


def override_functions(original_implementation: RecipeInterface):
    original_sign_in_up = original_implementation.sign_in_up

    async def sign_in_up(third_party_id: str, third_party_user_id: str, email: str,
                         user_context: Dict[str, Any]) -> SignInUpOkResult:
        if (is_not_allowed(email)):
            # this error will signal to the API to send a GENERAL_ERROR message
            raise Exception("Email not allowed")
        return await original_sign_in_up(third_party_id, third_party_user_id, email, user_context)
    original_implementation.sign_in_up = sign_in_up
    return original_implementation


def override_apis(original_implementation: APIInterface):
    # first we copy the original implementation
    original_sign_in_up_post = original_implementation.sign_in_up_post

    async def sign_in_up_post(provider: Provider, code: str, redirect_uri: str, client_id: Union[str, None], auth_code_response: Union[Dict[str, Any], None], api_options: APIOptions,
                              user_context: Dict[str, Any]) -> Union[SignInUpPostOkResult, SignInUpPostNoEmailGivenByProviderResponse, GeneralErrorResponse]:
        try:
            return await original_sign_in_up_post(provider, code, redirect_uri, client_id, auth_code_response, api_options, user_context)
        except Exception as e:
            if(str(e) == "Email not allowed"):
                return GeneralErrorResponse(message="You are not allowed to sign up. Please contact the app's admin to get permission")
            raise e

    original_implementation.sign_in_up_post = sign_in_up_post

    return original_implementation


def is_not_allowed(email: str):
    # TODO: your impl to check if the email is allowed
    return True


thirdparty.init(
    sign_in_and_up_feature=thirdparty.SignInAndUpFeature([]),
    override=thirdparty.InputOverrideConfig(
        apis=override_apis,
        functions=override_functions
    )
)