improve downloading GPX+KML:

- "Content-Disposition: attachment" header with "filename"
- specific mime-types
resolves nrenner/brouter-web#6

brouter-server/src/main/java/btools/server/RouteServer.java

@@ -105,7 +105,7 @@ public class RouteServer extends Thread
             else
             {
               OsmTrack track = cr.getFoundTrack();
-              writeHttpHeader(bw, handler.getMimeType());
+              writeHttpHeader(bw, handler.getMimeType(), handler.getFileName());
               if ( track != null )
               {
                 bw.write( handler.formatTrack(track) );
@@ -211,11 +211,20 @@ public class RouteServer extends Thread
   }
 
   private static void writeHttpHeader( BufferedWriter bw, String mimeType ) throws IOException
+  {
+    writeHttpHeader( bw, mimeType, null );
+  }
+
+  private static void writeHttpHeader( BufferedWriter bw, String mimeType, String fileName ) throws IOException
   {
     // http-header
     bw.write( "HTTP/1.1 200 OK\n" );
     bw.write( "Connection: close\n" );
     bw.write( "Content-Type: " + mimeType + "; charset=utf-8\n" );
+    if ( fileName != null )
+    {
+      bw.write( "Content-Disposition: attachment; filename=" + fileName + "\n" );
+    }
     bw.write( "Access-Control-Allow-Origin: *\n" );
     bw.write( "\n" );
   }

brouter-server/src/main/java/btools/server/request/RequestHandler.java

@@ -26,4 +26,6 @@ public abstract class RequestHandler
 	public abstract String formatTrack(OsmTrack track);
 
   public abstract String getMimeType();
+
+  public abstract String getFileName();
 }

brouter-server/src/main/java/btools/server/request/ServerHandler.java

@@ -133,9 +133,13 @@ public class ServerHandler extends RequestHandler {
     String format = params.get( "format" );
     if ( format != null )
     {
-      if ( "gpx".equals( format ) || "kml".equals( format ) )
+      if ( "gpx".equals( format ) )
       {
-        result = "text/xml";
+        result = "application/gpx+xml";
+      }
+      else if ( "kml".equals( format ) )
+      {
+        result = "application/vnd.google-earth.kml+xml";
       }
       else if ( "csv".equals( format ) )
       {
@@ -146,6 +150,20 @@ public class ServerHandler extends RequestHandler {
     return result;
   }
 
+  @Override
+  public String getFileName()
+  {
+    String fileName = null;
+    String format = params.get( "format" );
+
+    if ( format != null )
+    {
+      fileName = "brouter." + format;
+    }
+
+    return fileName;
+  }
+
   private static OsmNodeNamed readPosition( String vlon, String vlat, String name )
   {
     if ( vlon == null ) throw new IllegalArgumentException( "lon " + name + " not found in input" );