Friday, December 20, 2013

Access to services from gsp views in Grails

Accessing services from views is considered bad practice, so there is no easy way to do it. It defenitely should not be overused, as it complicates testing and couples logic with presentation. However it is not necessary crime and can be handy for some cases.

For example, if you need access to user parameters. Traditional way to do it, is by using taglibs. What is less known is that you can use taglibs not just to produce text output, but also inside snippets of code in views. For example, you can use it to select users preferred language without need to inject it into every controller:

Taglib:

class UserSettingsTagLib {
    def springSecurityService

    def myLanguage = { attrs, body ->
      out << springSecurityService.currentUser?.myLanguage?.id
    }

}


Gsp:

<g:select name="language" optionKey="id" optionValue="name" value="${g.myLanguage()}" from="${Language.list().sort{it.name}}"/>