Grails i18n From Database but Default Back To File

Question

Following this blog article I enabled my application to load i18n messages from the database. It works great. However, I don\'t want to manage all messages in the database

Answer 1

You may extend ReloadableResourceBundleMessageSource (the original grails message bundle, which does not seem to be final) instead and then apply this code:

class DatabaseMessageSource extends ReloadableResourceBundleMessageSource {
  protected MessageFormat resolveCode(String code, Locale locale) {
    Message msg = Message.findByCodeAndLocale(code, locale)
    def format = null
    if (msg) {
      format = new MessageFormat(msg.text, msg.locale)
    }else{
      format = super.resolveCode(code,locale)
    }
    return format;
  }
}

You may also reconfigure your message resources in Resources.groovy:

 beans = {
    messageSource(com.mycompany.DatabaseMessageSource) {
        basename = "WEB-INF/grails-app/i18n/messages"
    }
 }

Answer 2

I strongly encourage you to use Copycopter (http://copycopter.com) to manage i18n keys content. It will allow your team to update keys on the fly easily, using a friendly interface, and you will be able to set the default as you wanted. This way no one will come to you when a key needs to be updated.

ThoughtBot, a strong web development consulting company is behind that product. It is solid.

Your code will look like this then:

mail :to => member.email,
     :subject => I18n.translate("member_mailer.reminder_to_sign_in.#{underscored_number_of_days}.subject",
                                :default => %{You have not signed in for #{humanized_number_of_days}})

The i18n keys are generated on the fly on copytcopter, the first time you use it. It is really easy to use.

Check it out, it is worth it.

Answer 3

I would propose to keep one bundle-message-source in a new bean and inject it into your DatabaseMessageSource.

resources.groovy:

// Place your Spring DSL code here
beans = {
    messageSource(DatabaseMessageSource) {
        messageBundleMessageSource = ref("messageBundleMessageSource")
    }    
    messageBundleMessageSource(org.codehaus.groovy.grails.context.support.PluginAwareResourceBundleMessageSource) {
        basenames = "WEB-INF/grails-app/i18n/messages"
    }
}

DatabaseMessageSource.groovy:

class DatabaseMessageSource extends AbstractMessageSource {

    def messageBundleMessageSource

    protected MessageFormat resolveCode(String code, Locale locale) {
         Message msg = Message.findByCodeAndLocale(code, locale)
         def format
         if(msg) {
             format = new MessageFormat(msg.text, msg.locale)
         }
         else {
             format = messageBundleMessageSource.resolveCode(code, locale)
         }
         return format;
    }
}

This way, in fallback solution, the message will be read from the appropriate messages_*.properties file, by just requesting it from one resource bundle message source. Note that you should use the PluginAwareResourceBundleMessageSource, otherwise you could miss some important messages from your plugins.

Answer 4

Although it's not Grails specific, we at Griffon created CompositeResourceBundle and DelegatingResourceBundle as parts of our own i18n plugin (source found at http://svn.codehaus.org/griffon/plugins/griffon-i18n/trunk/src/main/griffon/plugins/i18n/).

ExtendedResourceBundleMessageSource shows how these classes can be used.

Answer 5

resolveCode(code, locale) in AbstractMessageSource is an abstract method so you will not be able to call it. Try extending ResourceBundleMessageSource or ReloadableResourceBundleMessageSource instead.