DownloadServlet.java

package org.kvj.lima1.gae.sync.rest;

import java.io.IOException;

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

import org.apache.amber.oauth2.common.OAuth;
import org.kvj.lima1.gae.sync.data.FileStorage;

import com.google.appengine.api.blobstore.BlobKey;
import com.google.appengine.api.blobstore.BlobstoreService;
import com.google.appengine.api.blobstore.BlobstoreServiceFactory;
import com.google.appengine.api.images.Image;
import com.google.appengine.api.images.ImagesService;
import com.google.appengine.api.images.ImagesService.OutputEncoding;
import com.google.appengine.api.images.ImagesServiceFactory;
import com.google.appengine.api.images.InputSettings;
import com.google.appengine.api.images.InputSettings.OrientationCorrection;
import com.google.appengine.api.images.OutputSettings;
import com.google.appengine.api.images.Transform;

public class DownloadServlet extends OAuthSecuredServlet {

	private static final long serialVersionUID = 1L;

	@Override
	protected void doGet(HttpServletRequest req, HttpServletResponse resp)
			throws ServletException, IOException {
		String app = req.getParameter("app");
		String name = req.getParameter("name");
		log.info("Getting file: " + name);
		BlobKey file = FileStorage.getFile(app,
				(String) req.getAttribute(OAuth.OAUTH_CLIENT_ID), name);
		if (null == file) {
			throw new ServletException("File not found");
		} else {
			BlobstoreService blobstoreService = BlobstoreServiceFactory
					.getBlobstoreService();
			resp.setHeader("Content-Type", "application/octet-stream");
			String width = req.getParameter("width");
			if (null != "width") {
				ImagesService imagesService = ImagesServiceFactory
						.getImagesService();
				Image fromBlob = ImagesServiceFactory.makeImageFromBlob(file);
				InputSettings inputSettings = new InputSettings();
				inputSettings
						.setOrientationCorrection(OrientationCorrection.CORRECT_ORIENTATION);
				OutputSettings outputSettings = new OutputSettings(
						OutputEncoding.JPEG);
				fromBlob = imagesService.applyTransform(
						ImagesServiceFactory.makeRotate(0), fromBlob,
						inputSettings, outputSettings);
				double mul = Double.parseDouble(width) / fromBlob.getWidth();
				// log.info("Transform image (with rotate) " +
				// fromBlob.getWidth()
				// + fromBlob.getHeight() + ", " + mul);
				Transform transform = ImagesServiceFactory.makeResize(
						(int) Math.ceil(fromBlob.getWidth() * mul),
						(int) Math.ceil(fromBlob.getHeight() * mul));
				Image outImage = imagesService.applyTransform(transform,
						fromBlob, inputSettings, outputSettings);
				resp.getOutputStream().write(outImage.getImageData());
				resp.flushBuffer();
				return;
			}
			blobstoreService.serve(file, resp);
		}
	}
}