README.md

nrich-webmvc

Overview

nrich-webmvc module provides additional functionality built on top of Spring Web MVC framework. Its main purpose is exception handling through NotificationErrorHandlingRestControllerAdvice and providing notification response to client. It also contains additional utility classes that disable binding of transient properties, convert empty strings to null etc.

Setting up Spring beans

nrich-webmvc module depends on nrich-logging and nrich-notification modules but users can provide their own implementations of NotificationResponseService and LoggingService.

@Configuration(proxyBeanMethods = false)
public class ApplicationConfiguration {

    @Bean
    public TransientPropertyResolverService transientPropertyResolverService() {
        return new DefaultTransientPropertyResolverService();
    }

    @Bean
    public ControllerEditorRegistrationAdvice controllerEditorRegistrationAdvice(TransientPropertyResolverService transientPropertyResolverService) {
        return new ControllerEditorRegistrationAdvice(true, true, transientPropertyResolverService);
    }

    @Bean
    public ExceptionAuxiliaryDataResolverService exceptionAuxiliaryDataResolverService() {
        return new DefaultExceptionAuxiliaryDataResolverService();
    }

    @Bean
    public ExceptionHttpStatusResolverService exceptionHttpStatusResolverService(MessageSource messageSource) {
        return new MessageSourceExceptionHttpStatusResolverService(messageSource);
    }

    @Bean
    public NotificationErrorHandlingRestControllerAdvice notificationErrorHandlingRestControllerAdvice(BaseNotificationResponseService<?> notificationResponseService, LoggingService loggingService, ExceptionAuxiliaryDataResolverService exceptionAuxiliaryDataResolverService, ExceptionHttpStatusResolverService exceptionHttpStatusResolverService) {
        return new NotificationErrorHandlingRestControllerAdvice(Collections.singletonList(ExecutionException.class.getName()), Collections.singletonList("uuid"), notificationResponseService, loggingService, exceptionAuxiliaryDataResolverService, exceptionHttpStatusResolverService);
    }

    @Bean
    public ConstrainedSessionLocaleResolver constrainedSessionLocaleResolver() {
        return new ConstrainedSessionLocaleResolver("en", Arrays.asList("en", "hr"));
    }
}

TransientPropertyResolverService resolves a list of transient properties for type.

ControllerEditorRegistrationAdvice converts empty strings to null and disables binding of transient properties (it accepts arguments that decide if binding should be disabled and if empty strings should be converted to null).

ExceptionAuxiliaryDataResolverService resolves additional data for each exception that will be logged and (if configured) sent to client with notification (this can be current time, uuid etc). Default implementation returns uuid, current time, request uri and request method.

ExceptionHttpStatusResolverService resolves http status for each exception. Default implementation MessageSourceExceptionHttpStatusResolverService resolves status by using Spring's MessageSource. Message code for resolving is fullyQualifiedExceptionName.httpStatus

NotificationErrorHandlingRestControllerAdvice is responsible for logging errors, resolving addition data for notifications, creating notification and converting them to response for the client. It accepts a list of exceptions that contain original exceptions as cause properties (i.e. ExecutionException), a list of exception auxiliary data to be included in notification and services that are used for logging, data resolving and notification creation.

ConstrainedSessionLocaleResolver is used when we want to limit locale selection.

Usage

For usage it is enough to add module as dependency and set up beans. NotificationErrorHandlingRestControllerAdvice handles all exceptions thrown by user code (including binding and validation exceptions) and it uses LoggingService to log errors and NotificationResponseService to create notifications that are sent to client in JSON format.

Example response on exception is:

{
    "notification": {
        "title": "Error",
        "content": "Error occurred",
        "messageList": [],
        "severity": "ERROR"
    }
}