XPages: The Outputstream and binary data

As wiritten in the comments, Verne is correct. I just missed the „facesContext.responseComplete()“ in the beforeRenderResponse event.

If you want to get control over the outputstream of a XPage, you can use the response object from the ExternalContext:

var response = facesContext.getExternalContext().getResponse()

This will give you access to an object of type com.ibm.xsp.webapp.XspHttpServletResponse which allows some basic operations, but the response will always be encoded to UTF-8. You can not return any binary data directly.

But if you access the underlying LCDAdapterHttpServletResponse directly, it is possible to get the full control for the outputstream.

var exCon = facesContext.getExternalContext();
var response = exCon.getResponse().getDelegate();

This allows you to send any data you want to the browser. Here is an example for a JPEG rendered directly in the XPage:

1. The XPage

<?xml version="1.0" encoding="UTF-8"?>
<xp:view xmlns:xp="http://www.ibm.com/xsp/core" rendered="true">

   <xp:this.afterRenderResponse>
      <![CDATA[#{javascript:
         importPackage( ch.hasselba.xpages.demo );
         var exCon = facesContext.getExternalContext();
         var response = exCon.getResponse().getDelegate();
         ch.hasselba.xpages.demo.JPEGGenerator.generate( response );
      }]]>
   </xp:this.afterRenderResponse>

</xp:view>

2. The Java object to generate a JPEG

package ch.hasselba.xpages.demo;

import javax.servlet.ServletOutputStream;
import javax.servlet.http.HttpServletResponse;
import java.awt.Graphics;
import java.awt.image.BufferedImage;
import java.io.IOException;
import com.sun.image.codec.jpeg.ImageFormatException;
import com.sun.image.codec.jpeg.JPEGCodec;
import java.awt.Color;
import java.awt.Font;

/**
 * JPEG Generator for a simple demonstration of controlling the
 * HttpServletResponse output
 * 
 * @author Sven Hasselbach
 * @category Demo
 * @category Servlet
 * @category Image
 * @version 1.0
 */

public class JPEGGenerator {

    private static final long serialVersionUID = 1L;
    private static final int WIDTH = 800;
    private static final int HEIGHT = 200;
    private static final Color BACKGROUND_COLOR = new Color(224, 224, 224);
    private static final Color COLOR = new Color(0, 0, 0);
    private static final Font FONT = new Font("Times New Roman", Font.BOLD, 46);

    /**
     * generates a JPEG image and sends the result to the outputstream of the
     * HttpServlet
     * 
     * @param response
     *            HttpServletResponse
     * @author Sven Hasselbach
     * @version 1.0
     */
    public static void generate(final HttpServletResponse response) {
        ServletOutputStream out = null;
        try {

            // set the content type for JPEG
            response.setContentType("image/jpg");

            // get the ouput stream
            out = response.getOutputStream();

            // generate a image to convert
            BufferedImage img = createImage();

            // convert image to jpeg and send to output
            JPEGCodec.createJPEGEncoder(out).encode(img);

        } catch (ImageFormatException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }

    }

    /**
     * creates a simple "Hello World" image
     * 
     * @return BufferedImage
     * @author Sven Hasselbach
     * @version 1.0
     */
    public static BufferedImage createImage() {
        BufferedImage image = new BufferedImage(WIDTH, HEIGHT,
                BufferedImage.TYPE_BYTE_INDEXED);
        Graphics graphics = image.getGraphics();
        graphics.setColor(BACKGROUND_COLOR);
        graphics.fillRect(0, 0, image.getWidth(), image.getHeight());
        graphics.setColor(COLOR);
        graphics.setFont(FONT);
        graphics.drawString("Hello World!", 10, HEIGHT / 2);

        return image;
    }

}

There is no need for splitting this example in a separated Java class. You can directly access the output in SSJS and send your binary data directly via write method of the ServletOutputStream.