Developing with Grails and Groovy can be a blessing and and pain all at the same time. The development moves at a rapid rate but when you decide to include libraries that depend on other libraries, your pain starts to build up. For example, when you include the module “HttpBuilder”in your project you may run into issues with Xerces and xml-apis, especially when you attempt to deploy the WAR file under Tomcat. These libraries are included as part of Tomcat and so an older version of those classes may give you a heartburn.

If your objective is to use some raw HTTP classes to create your requests and responses, then you can use the basic URL class to do most of the raw connection options. Although using HttpBuilder makes it a clean implementation, the URL class gives you very similar power without all the overhead of including the dependency classes.

def urlConnect = new URL(url)
def connection = urlConnect.openConnection()
//Set all of your needed headers
connection.setRequestProperty("X-Forwarded-For", "<your ip address>")

if(connection.responseCode == 200){
responseText = connection.content.text
}
else{
println "An error occurred:"
println connection.responseCode
println connection.responseMessage
}

So the trick to the Groovy URL class is to use the “openConnection()” method and then gain access to some of the raw functionality.

Cheers.

From http://mythinkpond.wordpress.com/2011/10/24/grails-groovy-alternative-to-httpbuilder-adding-headers-to-your-http-request/