groovy - Open or download URL link in Grails Controller -

i want render or download url links pdf in grails controller method. i'm okay either opening in new or same tab, or downloading it. how done in grails?

so far have:

render(url: "http://test.com/my.pdf") 

however, errors , other ways i've tried, such rendering response content. clues?

one option is

class examplecontroller {     def download() {         redirect(url: "http://www.pdf995.com/samples/pdf.pdf")     } } 

going localhost:8080/appname/example/download will, depending on users browser preferences, either download file or open file in same tab reading.

i works grails 2.5.0