FileUtil.java

/*******************************************************************************
 * Copyright 2012 University of Southern California
 * 
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 * 
 * 	http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 * 
 * This code was developed by the Information Integration Group as part 
 * of the Karma project at the Information Sciences Institute of the 
 * University of Southern California.  For more information, publications, 
 * and related projects, please see: http://www.isi.edu/integration
 ******************************************************************************/
package edu.isi.karma.util;

import java.io.BufferedWriter;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.FileWriter;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.io.OutputStreamWriter;
import java.io.PrintWriter;
import java.io.UnsupportedEncodingException;
import java.nio.MappedByteBuffer;
import java.nio.channels.FileChannel;
import java.nio.charset.Charset;
import java.util.Iterator;
import java.util.List;

import javax.servlet.http.HttpServletRequest;

import org.apache.commons.fileupload.FileItem;
import org.apache.commons.fileupload.FileUploadException;
import org.apache.commons.fileupload.disk.DiskFileItemFactory;
import org.apache.commons.fileupload.servlet.ServletFileUpload;
import org.json.JSONException;
import org.json.JSONObject;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import edu.isi.karma.webserver.ServletContextParameterMap;
import edu.isi.karma.webserver.ServletContextParameterMap.ContextParameter;

public class FileUtil {
	private static String DESTINATION_DIR_PATH = ServletContextParameterMap.getParameterValue(ContextParameter.USER_DIRECTORY_PATH) + 
			"UserUploadedFiles/";
	private static Logger logger = LoggerFactory.getLogger(FileUtil.class);
	
	static public File downloadFileFromHTTPRequest (HttpServletRequest request) {
		// Download the file to the upload file folder
		File destinationDir = new File(DESTINATION_DIR_PATH);
		logger.debug("File upload destination directory: " + destinationDir.getAbsolutePath());
		if(!destinationDir.isDirectory()) {
			destinationDir.mkdir();
		}
		
		DiskFileItemFactory  fileItemFactory = new DiskFileItemFactory ();

		// Set the size threshold, above which content will be stored on disk.
		fileItemFactory.setSizeThreshold(1*1024*1024); //1 MB

		//Set the temporary directory to store the uploaded files of size above threshold.
		fileItemFactory.setRepository(destinationDir);
 
		ServletFileUpload uploadHandler = new ServletFileUpload(fileItemFactory);
		
		File uploadedFile = null;
		try {
			// Parse the request
			@SuppressWarnings("rawtypes")
			List items = uploadHandler.parseRequest(request);
			@SuppressWarnings("rawtypes")
			Iterator itr = items.iterator();
			while(itr.hasNext()) {
				FileItem item = (FileItem) itr.next();

				// Ignore Form Fields.
				if(item.isFormField()) {
					// Do nothing
				} else {
					//Handle Uploaded files. Write file to the ultimate location.
					uploadedFile = new File(destinationDir,item.getName());
					item.write(uploadedFile);
				}
			}
		} catch(FileUploadException ex) {
			logger.error("Error encountered while parsing the request",ex);
		} catch(Exception ex) {
			logger.error("Error encountered while uploading file",ex);
		}
		return uploadedFile;
	}

	public static void copyFiles(File destination, File source) throws FileNotFoundException, IOException{
		if(!destination.exists())
			destination.createNewFile();
		InputStream in = new FileInputStream(source);
		OutputStream out = new FileOutputStream(destination);

		byte[] buf = new byte[1024];
		int len;
		
		while ((len = in.read(buf)) > 0){
			out.write(buf, 0, len);
		}
		in.close();
		out.close();
		logger.debug("Done copying contents of " + source.getName() + " to " + destination.getName());
	}

	public static void writePrettyPrintedJSONObjectToFile(JSONObject json, File jsonFile) 
		throws JSONException, IOException{
		String prettyPrintedJSONString = json.toString(4);
		FileWriter writer = new FileWriter(jsonFile);
		writer.write(prettyPrintedJSONString);
		writer.close();
		logger.debug("Done writing JSON Object into a File: " + jsonFile.getAbsolutePath());
	}
	
	public static String readFileContentsToString (File file) throws IOException {
		 FileInputStream stream = new FileInputStream(file);
		  try {
		    FileChannel fc = stream.getChannel();
		    MappedByteBuffer bb = fc.map(FileChannel.MapMode.READ_ONLY, 0, fc.size());
		    /* Instead of using default, pass in a decoder. */
		    return Charset.defaultCharset().decode(bb).toString();
		  }
		  finally {
		    stream.close();
		  }
	}

	/**
	 * Saves a string to a file.
	 * @param str
	 * @param fileName
	 * @throws FileNotFoundException 
	 * @throws UnsupportedEncodingException 
	 */
	public static void writeStringToFile(String str, String fileName) throws UnsupportedEncodingException, FileNotFoundException{
		OutputStreamWriter fw = new OutputStreamWriter(new FileOutputStream(fileName),"UTF-8");
		BufferedWriter bw = new BufferedWriter (fw);
		PrintWriter outWriter = new PrintWriter (bw);
		outWriter.println(str);
		outWriter.close();
	}
	/* does not write UTF8
	public static void writeStringToFile(String string, String fileName) throws IOException {
		BufferedWriter writer = new BufferedWriter(new FileWriter(fileName));
		writer.write(string);
		writer.flush();
		writer.close();
	}
	*/
}