Friendly Error Messages for Grails

friendly_error_messages.groovy

class Bootstrap {
  def grailsApplication
  
  def messageSource
  
  def init = { servletContext ->
    for(dc in grailsApplication.domainClasses) {
      dc.metaClass.getErrorStrings = { Locale locale = Locale.getDefault() ->
        def stringsByField = [:].withDefault { [] }
        for(fieldErrors in delegate.errors) {
          for(error in fieldErrors.allErrors) {
            String message = messageSource.getMessage(error,locale)
            stringsByField[error.field] << message
          }
        }
        stringsByField
    }