Custom Error Handling

There are four types of errors:

• UnauthorisedException: This is when the user has been logged out, or session has expired.
• TryRefreshTokenException: This is when the access token has expired, and you need to refresh the session.
• TokenTheftDetectedException: This is thrown in case a user is being attacked. You can us this to revoke their affected session.
• GeneralException: This is thrown in case of any general error like failure when connecting to the SuperTokens core service.

Define error handlers using the SuperTokens.exceptionHandler() function

app.exception(SuperTokensException.class, SuperTokens.exceptionHandler()
    .onTryRefreshTokenError((exception, ctx) -> {
        // TODO:
    })
    .onUnauthorisedError((exception, ctx) -> {
        // TODO:
    })
    .onGeneralError(((exception, ctx) -> {
        // TODO:
    })
    .onTokenTheftDetectedError((exception, ctx) -> {
        // TODO:                    
    })
);

• All auth cookies are cleared when onUnauthorisedError and onTokenTheftDetectedError is called.
• You should respond with the same session expired HTTP status code for onUnauthorisedError and onTryRefreshTokenError. By default, this value is 440.
• By default, onTokenTheftDetectedError revokes the affected session and returns the session expired status code. In this function, you can use exception.getUserId() and exception.getSessionHandle() to get the affected user and session. Learn more about session handles here.
• You do not need to provide all theses callbacks.

Example

import io.supertokens.javalin.*;

app.exception(SuperTokensException.class, SuperTokens.exceptionHandler()
    .onTryRefreshTokenError((exception, ctx) -> {
        ctx.status(440).result("Call the refresh API");
    })
    .onUnauthorisedError((exception, ctx) -> {
        ctx.status(440).result("Please login again");
    })
    .onGeneralError(((exception, ctx) -> {
        ctx.status(440).result(exception.getMessage());
    })
    .onTokenTheftDetectedError((exception, ctx) -> {
        ctx.status(440).result("You are being attacked");  

        // revoke affected session.   
        try {
            SuperTokens.revokeSession(exception.getSessionHandle());  
        } catch (GeneralException e) {
            e.printStackTrace();
        }
    })
);