Writing a proxy in grails - http

Question

I am using Gralis 1.3.7. I am writing a controller that needs to get a PDF file from another server and return it to the client. I would like to do this in some reasonably efficient manner, such as the following:
class DocController {
def view = {
URL source = new URL("http://server.com?docid=${params.docid}");
response.contentType = 'application/pdf';
// Something like this to set the content length
response.setHeader("Content-Length", source.contentLength.toString());
response << source.openStream();
}
}
The problem I am having is figuring out how to set the content length of the response of my controller based on the information coming back from source. I wasn't able to find the documentation on the URL class as enhanced by grails.
What's the best way to proceed?
Gene
EDITED: Fixed parameter values in setHeader
UPDATED 16 mar 2012 10:49 PST
UPDATED 19 March 2012 10:45 PST
Moved follow-up to a separate question.

Answer 1

You can use java.net.URLConnection object that will allow you to do a bit more detailed work with the URL.
URLConnection connection = new URL(url).openConnection()
def url = new URL("http://www.aboutgroovy.com")
def connection = url.openConnection()
println connection.responseCode // ===> 200
println connection.responseMessage // ===> OK
println connection.contentLength // ===> 4216
println connection.contentType // ===> text/html
println connection.date // ===> 1191250061000
println connection.lastModified
// print headers
connection.headerFields.each{println it}
Your example should looks something like this:
class DocController {
def view = {
URL source = new URL("http://server.com?docid=${params.docid}");
URLConnection connection = source.openConnection();
response.contentType = 'application/pdf';
// Set the content length
response.setHeader("Content-Length", connection.contentLength.toString());
// Get the input stream from the connection
response.outputStream << connection.getInputStream();
}
}