gistfile1.java

package com.servlet;

import java.io.IOException;
import java.util.List;
import java.util.Map;
import java.util.logging.Level;
import java.util.logging.Logger;

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

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.blobstore.UploadOptions;
import com.google.appengine.api.images.ImagesServiceFactory;
import com.google.appengine.api.images.ImagesServiceFailureException;
import com.google.appengine.api.images.ServingUrlOptions;

public class UploadHandler extends HttpServlet {
    
    private static final String BUCKET_NAME = "[YOUR_BUCKET_NAME]";
    private static final String JSON_CONTENT_TYPE = "application/json; charset=UTF-8";
    private static final Logger logger = Logger.getLogger(Upload.class.getName());

    @Override
    public void doGet(HttpServletRequest request, HttpServletResponse response) throws IOException {
	    BlobstoreService blobstoreService = BlobstoreServiceFactory.getBlobstoreService();
	    UploadOptions uploadOptions = null;
	    String environment = System.getProperty("com.google.appengine.runtime.environment");
	    String bucket = null;
	    if ("Production".equalsIgnoreCase(environment)) {
	        bucket = BUCKET_NAME;
	    }
	    if (bucket == null || bucket.isEmpty()) {
	        uploadOptions = UploadOptions.Builder.withDefaults();
	    } else {
	        uploadOptions = UploadOptions.Builder.withGoogleStorageBucketName(bucket);
	    }
	    String uploadUrl = blobstoreService.createUploadUrl("/upload", uploadOptions);
	    
	    String successJSON = "{\"success\":\"true\", \"data\":\"" + uploadUrl + "\"}";
	    response.setContentType(JSON_CONTENT_TYPE);
	    try {
	        response.getWriter().write(successJSON);
	    } catch (IOException e) {
	        logger.log(Level.SEVERE, "Error sending response", e);
	    }
    }

    @Override
    public void doPost(HttpServletRequest req, HttpServletResponse res) throws IOException {
	    BlobstoreService blobstoreService = BlobstoreServiceFactory.getBlobstoreService();
	    Map<String, List<BlobKey>> blobs = blobstoreService.getUploads(req);
	    for (String key : blobs.keySet()) {
	        logger.info("BLOB KEY:" + key);
	    }
	    List<BlobKey> keys = blobs.get("userfile");
	    if (keys != null && keys.size() > 0) {
            String title = req.getParameter("filename");
	        BlobKey blobKey = keys.get(0);
	        
	        //this is response data to client you can have any other format!
	        String successJSON = "{\"success\":\"true\",\"filename\":\"" + title + "\", \"mainUrl\":\"" + getPhotoDisplayUrl(blobKey)
		    + "\", \"secondaryUrl\":\"" + getThumbnailUrl(blobKey) + "\"}";
	        
	        logger.info("UPLOAD RESPONSE JSON:" + successJSON);
	        res.setContentType(JSON_CONTENT_TYPE);
	        
	        try {
		        res.getWriter().write(successJSON);
	        } catch (IOException e) {
		        logger.log(Level.SEVERE, "Error sending response", e);
	        }
	    } else {
	        logger.info("UPLOAD FAILED");
	        res.sendError(400, "Request cannot be handled.");
	    }
    }

    /*Get thumbnail image of size 100x100 using blob key*/
    public String getThumbnailUrl(BlobKey blobKey) {
	    ServingUrlOptions options = ServingUrlOptions.Builder.withBlobKey(blobKey);
	    options.imageSize(100);
	    options.crop(true);
	    try {
	        return ImagesServiceFactory.getImagesService().getServingUrl(options);
	    } catch (ImagesServiceFailureException e) {
	        logger.severe("Failed to get image serving url: " + e.getMessage());
	        return "";
	    } catch (Exception e) {
	        logger.severe("Invalid blob key: " + e.getMessage());
	        return "";
	    }
    }

    public String getPhotoDisplayUrl(BlobKey blobKey) {
	    ServingUrlOptions options = ServingUrlOptions.Builder.withBlobKey(blobKey);
	    options.imageSize(1024);
	    options.crop(false);
	    try {
	        return ImagesServiceFactory.getImagesService().getServingUrl(options);
	    } catch (ImagesServiceFailureException e) {
	        logger.severe("Failed to get image serving url: " + e.getMessage());
	        return "";
	    }
    }
}