the server name in the arguments also need to take the reverse proxy into account.

git-svn-id: https://hudson.dev.java.net/svn/hudson/trunk/hudson/main@10543 71c3de6d-444a-0410-be80-ed276b4c234a

core/src/main/java/hudson/Functions.java

@@ -55,6 +55,8 @@ import java.lang.management.ThreadInfo;
 import java.lang.management.ThreadMXBean;
 import java.net.URI;
 import java.net.URISyntaxException;
+import java.net.URL;
+import java.net.MalformedURLException;
 import java.util.Calendar;
 import java.util.Collection;
 import java.util.Collections;
@@ -885,5 +887,26 @@ public class Functions {
         return System.getProperty(key);
     }
 
+    /**
+     * Obtains the host name of the Hudson server that clients can use to talk back to.
+     * <p>
+     * This is primarily used in <tt>slave-agent.jnlp.jelly</tt> to specify the destination
+     * that the slaves talk to.
+     */
+    public String getServerName() {
+        // try to infer this from the request URL
+        String url = Hudson.getInstance().getRootUrl();
+        try {
+            if(url!=null) {
+                String host = new URL(url).getHost();
+                if(host!=null)
+                    return host;
+            }
+        } catch (MalformedURLException e) {
+            // fall back to HTTP request
+        }
+        return Stapler.getCurrentRequest().getServerName();
+    }
+
     private static final Pattern SCHEME = Pattern.compile("[a-z]+://.+");
 }