[jetty-users] Is there a way to avoid this?

[Steve Sobol - Lobos Studios <steve@xxxxxxxxxxxxxxxx>]

There has to be a simple answer to this... I have a servlet that serves a PNG file if it exists, and if it doesn't, throws an HTTP 404 error and serves a default image. In the second case, I get the default image but I see this in the logs. I checked and couldn't find an obvious way to set the HTTP status code without committing the response...

2015-01-28 14:35:06.318:WARN:oejs.ServletHandler:/featured-event-image/event1-1.png
java.lang.IllegalStateException: Committed
    at org.eclipse.jetty.server.Response.resetBuffer(Response.java:1090)
    at org.eclipse.jetty.server.Response.reset(Response.java:1034)
    at com.mymitzvahdate.servlet.FeaturedEventImage.doGet(FeaturedEventImage.java:53)

This is the servlet:

package com.mymitzvahdate.servlet;

import java.io.File;
import java.io.IOException;
import java.net.URLDecoder;
import java.nio.file.Files;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import com.mymitzvahdate.Constants;
import com.mymitzvahdate.persistence.Globals;


public class FeaturedEventImage extends HttpServlet {

    public static final long serialVersionUID = 1L;
   
    // Properties ---------------------------------------------------------------------------------

    private String imagePath, defaultImagePath;

    // Actions ------------------------------------------------------------------------------------

    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {

        imagePath = Globals.get(Constants.GLOBAL_FEATURED_IMAGE_DIR);
        defaultImagePath = Globals.get(Constants.GLOBAL_DEFAULT_FEATURED_IMAGE);

        // Get requested image by path info.
        String requestedImage = request.getPathInfo();

        // Check if file name is actually supplied to the request URI.
        if (requestedImage == null) {
            sendErrorAndDefaultPNG(response);
        }

        // Decode the file name
        String imageFilename = URLDecoder.decode(requestedImage, "UTF-8");
       
        // chop off the extension if one exists
        if (imageFilename.lastIndexOf(".")> -1) imageFilename = imageFilename.substring(0,imageFilename.lastIndexOf("."));

        File image = new File(imagePath, imageFilename + ".jpg");
       
        // Check if file actually exists in filesystem.
        if (!image.exists()) {
            sendErrorAndDefaultPNG(response);
        }
       
        response.reset();
        sendImage(response, image);

    }

    private void sendImage(HttpServletResponse response, File image) {
        response.setContentType("image/png");
        response.setHeader("Content-Length", String.valueOf(image.length()));
        try {
            Files.copy(image.toPath(), response.getOutputStream());
        } catch(IOException exc) {
        }
    }
 
   
    private void sendErrorAndDefaultPNG(HttpServletResponse response) {
        response.reset();
        response.setStatus(HttpServletResponse.SC_NOT_FOUND); // 404.
        File errorImage = new File(imagePath, defaultImagePath);
        sendImage(response, errorImage);
       
        return;
    }
   
   
}


Thanks for whatever help you can offer

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