wicket/src/java/wicket/util/upload/DiskFileItem.java

/*
 * Copyright 2001-2004 The Apache Software Foundation
 * 
 * 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.
 */
package wicket.util.upload;

import java.io.BufferedInputStream;
import java.io.BufferedOutputStream;
import java.io.ByteArrayInputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.io.UnsupportedEncodingException;
import java.util.Map;

import wicket.WicketRuntimeException;
import wicket.util.file.FileCleaner;
import wicket.util.io.DeferredFileOutputStream;


/**
 * <p>
 * The default implementation of the
 * {@link wicket.util.upload.FileItem FileItem} interface.
 * 
 * <p>
 * After retrieving an instance of this class, you may either request all
 * contents of file at once using {@link #get()} or request an
 * {@link java.io.InputStream InputStream} with {@link #getInputStream()} and
 * process the file without attempting to load it into memory, which may come
 * handy with large files.
 * 
 * @author <a href="mailto:Rafal.Krzewski@e-point.pl">Rafal Krzewski</a>
 * @author <a href="mailto:sean@informage.net">Sean Legassick</a>
 * @author <a href="mailto:jvanzyl@apache.org">Jason van Zyl</a>
 * @author <a href="mailto:jmcnally@apache.org">John McNally</a>
 * @author <a href="mailto:martinc@apache.org">Martin Cooper</a>
 * @author Sean C. Sullivan
 * 
 * @since FileUpload 1.1
 * 
 * @version $Id$
 */
public class DiskFileItem implements FileItem
{

	private static final long serialVersionUID = 1L;

	// ----------------------------------------------------- Manifest constants


	/**
	 * Default content charset to be used when no explicit charset parameter is
	 * provided by the sender. Media subtypes of the "text" type are defined to
	 * have a default charset value of "ISO-8859-1" when received via HTTP.
	 */
	public static final String DEFAULT_CHARSET = "ISO-8859-1";


	/**
	 * Size of buffer to use when writing an item to disk.
	 */
	private static final int WRITE_BUFFER_SIZE = 2048;


	// ----------------------------------------------------------- Data members


	/**
	 * Counter used in unique identifier generation.
	 */
	private static int counter = 0;


	/**
	 * The name of the form field as provided by the browser.
	 */
	private String fieldName;


	/**
	 * The content type passed by the browser, or <code>null</code> if not
	 * defined.
	 */
	private String contentType;


	/**
	 * Whether or not this item is a simple form field.
	 */
	private boolean isFormField;


	/**
	 * The original filename in the user's filesystem.
	 */
	private String fileName;


	/**
	 * The threshold above which uploads will be stored on disk.
	 */
	private int sizeThreshold;


	/**
	 * The directory in which uploaded files will be stored, if stored on disk.
	 */
	private File repository;


	/**
	 * Cached contents of the file.
	 */
	private byte[] cachedContent;


	/**
	 * Output stream for this item.
	 */
	private DeferredFileOutputStream dfos;


	// ----------------------------------------------------------- Constructors


	/**
	 * Constructs a new <code>DiskFileItem</code> instance.
	 * 
	 * @param fieldName
	 *            The name of the form field.
	 * @param contentType
	 *            The content type passed by the browser or <code>null</code>
	 *            if not specified.
	 * @param isFormField
	 *            Whether or not this item is a plain form field, as opposed to
	 *            a file upload.
	 * @param fileName
	 *            The original filename in the user's filesystem, or
	 *            <code>null</code> if not specified.
	 * @param sizeThreshold
	 *            The threshold, in bytes, below which items will be retained in
	 *            memory and above which they will be stored as a file.
	 * @param repository
	 *            The data repository, which is the directory in which files
	 *            will be created, should the item size exceed the threshold.
	 */
	public DiskFileItem(String fieldName, String contentType, boolean isFormField, String fileName,
			int sizeThreshold, File repository)
	{
		this.fieldName = fieldName;
		this.contentType = contentType;
		this.isFormField = isFormField;
		this.fileName = fileName;
		this.sizeThreshold = sizeThreshold;
		this.repository = repository;
	}


	// ------------------------------- Methods from javax.activation.DataSource


	/**
	 * Returns an {@link java.io.InputStream InputStream} that can be used to
	 * retrieve the contents of the file.
	 * 
	 * @return An {@link java.io.InputStream InputStream} that can be used to
	 *         retrieve the contents of the file.
	 * 
	 * @exception IOException
	 *                if an error occurs.
	 */
	public InputStream getInputStream() throws IOException
	{
		if (!dfos.isInMemory())
		{
			return new FileInputStream(dfos.getFile());
		}

		if (cachedContent == null)
		{
			cachedContent = dfos.getData();
		}
		return new ByteArrayInputStream(cachedContent);
	}


	/**
	 * Returns the content type passed by the agent or <code>null</code> if
	 * not defined.
	 * 
	 * @return The content type passed by the agent or <code>null</code> if
	 *         not defined.
	 */
	public String getContentType()
	{
		return contentType;
	}


	/**
	 * Returns the content charset passed by the agent or <code>null</code> if
	 * not defined.
	 * 
	 * @return The content charset passed by the agent or <code>null</code> if
	 *         not defined.
	 */
	public String getCharSet()
	{
		ParameterParser parser = new ParameterParser();
		parser.setLowerCaseNames(true);
		// Parameter parser can handle null input
		Map params = parser.parse(getContentType(), ';');
		return (String)params.get("charset");
	}


	/**
	 * Returns the original filename in the client's filesystem.
	 * 
	 * @return The original filename in the client's filesystem.
	 */
	public String getName()
	{
		return fileName;
	}


	// ------------------------------------------------------- FileItem methods


	/**
	 * Provides a hint as to whether or not the file contents will be read from
	 * memory.
	 * 
	 * @return <code>true</code> if the file contents will be read from
	 *         memory; <code>false</code> otherwise.
	 */
	public boolean isInMemory()
	{
		return (dfos.isInMemory());
	}


	/**
	 * Returns the size of the file.
	 * 
	 * @return The size of the file, in bytes.
	 */
	public long getSize()
	{
		if (cachedContent != null)
		{
			return cachedContent.length;
		}
		else if (dfos.isInMemory())
		{
			return dfos.getData().length;
		}
		else
		{
			return dfos.getFile().length();
		}
	}


	/**
	 * Returns the contents of the file as an array of bytes. If the contents of
	 * the file were not yet cached in memory, they will be loaded from the disk
	 * storage and cached.
	 * 
	 * @return The contents of the file as an array of bytes.
	 */
	public byte[] get()
	{
		if (dfos.isInMemory())
		{
			if (cachedContent == null)
			{
				cachedContent = dfos.getData();
			}
			return cachedContent;
		}

		byte[] fileData = new byte[(int)getSize()];
		FileInputStream fis = null;

		try
		{
			fis = new FileInputStream(dfos.getFile());
			fis.read(fileData);
		}
		catch (IOException e)
		{
			fileData = null;
		}
		finally
		{
			if (fis != null)
			{
				try
				{
					fis.close();
				}
				catch (IOException e)
				{
					// ignore
				}
			}
		}

		return fileData;
	}


	/**
	 * Returns the contents of the file as a String, using the specified
	 * encoding. This method uses {@link #get()} to retrieve the contents of the
	 * file.
	 * 
	 * @param charset
	 *            The charset to use.
	 * 
	 * @return The contents of the file, as a string.
	 * 
	 * @exception UnsupportedEncodingException
	 *                if the requested character encoding is not available.
	 */
	public String getString(final String charset) throws UnsupportedEncodingException
	{
		return new String(get(), charset);
	}


	/**
	 * Returns the contents of the file as a String, using the default character
	 * encoding. This method uses {@link #get()} to retrieve the contents of the
	 * file.
	 * 
	 * @return The contents of the file, as a string.
	 * 
	 * @todo Consider making this method throw UnsupportedEncodingException.
	 */
	public String getString()
	{
		byte[] rawdata = get();
		String charset = getCharSet();
		if (charset == null)
		{
			charset = DEFAULT_CHARSET;
		}
		try
		{
			return new String(rawdata, charset);
		}
		catch (UnsupportedEncodingException e)
		{
			return new String(rawdata);
		}
	}


	/**
	 * A convenience method to write an uploaded item to disk. The client code
	 * is not concerned with whether or not the item is stored in memory, or on
	 * disk in a temporary location. They just want to write the uploaded item
	 * to a file.
	 * <p>
	 * This implementation first attempts to rename the uploaded item to the
	 * specified destination file, if the item was originally written to disk.
	 * Otherwise, the data will be copied to the specified file.
	 * <p>
	 * This method is only guaranteed to work <em>once</em>, the first time
	 * it is invoked for a particular item. This is because, in the event that
	 * the method renames a temporary file, that file will no longer be
	 * available to copy or rename again at a later time.
	 * 
	 * @param file
	 *            The <code>File</code> into which the uploaded item should be
	 *            stored.
	 * 
	 * @exception Exception
	 *                if an error occurs.
	 */
	public void write(File file) throws Exception
	{
		if (isInMemory())
		{
			FileOutputStream fout = null;
			try
			{
				fout = new FileOutputStream(file);
				fout.write(get());
			}
			finally
			{
				if (fout != null)
				{
					fout.close();
				}
			}
		}
		else
		{
			File outputFile = getStoreLocation();
			if (outputFile != null)
			{
				/*
				 * The uploaded file is being stored on disk in a temporary
				 * location so move it to the desired file.
				 */
				if (!outputFile.renameTo(file))
				{
					BufferedInputStream in = null;
					BufferedOutputStream out = null;
					try
					{
						in = new BufferedInputStream(new FileInputStream(outputFile));
						out = new BufferedOutputStream(new FileOutputStream(file));
						byte[] bytes = new byte[WRITE_BUFFER_SIZE];
						int s = 0;
						while ((s = in.read(bytes)) != -1)
						{
							out.write(bytes, 0, s);
						}
					}
					finally
					{
						if (in != null)
						{
							try
							{
								in.close();
							}
							catch (IOException e)
							{
								// ignore
							}
						}
						if (out != null)
						{
							try
							{
								out.close();
							}
							catch (IOException e)
							{
								// ignore
							}
						}
					}
				}
			}
			else
			{
				/*
				 * For whatever reason we cannot write the file to disk.
				 */
				throw new FileUploadException("Cannot write uploaded file to disk!");
			}
		}
	}


	/**
	 * Deletes the underlying storage for a file item, including deleting any
	 * associated temporary disk file. Although this storage will be deleted
	 * automatically when the <code>FileItem</code> instance is garbage
	 * collected, this method can be used to ensure that this is done at an
	 * earlier time, thus preserving system resources.
	 */
	public void delete()
	{
		cachedContent = null;
		File outputFile = getStoreLocation();
		if (outputFile != null && outputFile.exists())
		{
			outputFile.delete();
		}
	}


	/**
	 * Returns the name of the field in the multipart form corresponding to this
	 * file item.
	 * 
	 * @return The name of the form field.
	 * 
	 * @see #setFieldName(java.lang.String)
	 * 
	 */
	public String getFieldName()
	{
		return fieldName;
	}


	/**
	 * Sets the field name used to reference this file item.
	 * 
	 * @param fieldName
	 *            The name of the form field.
	 * 
	 * @see #getFieldName()
	 * 
	 */
	public void setFieldName(String fieldName)
	{
		this.fieldName = fieldName;
	}


	/**
	 * Determines whether or not a <code>FileItem</code> instance represents a
	 * simple form field.
	 * 
	 * @return <code>true</code> if the instance represents a simple form
	 *         field; <code>false</code> if it represents an uploaded file.
	 * 
	 * @see #setFormField(boolean)
	 * 
	 */
	public boolean isFormField()
	{
		return isFormField;
	}


	/**
	 * Specifies whether or not a <code>FileItem</code> instance represents a
	 * simple form field.
	 * 
	 * @param state
	 *            <code>true</code> if the instance represents a simple form
	 *            field; <code>false</code> if it represents an uploaded file.
	 * 
	 * @see #isFormField()
	 * 
	 */
	public void setFormField(boolean state)
	{
		isFormField = state;
	}


	/**
	 * Returns an {@link java.io.OutputStream OutputStream} that can be used for
	 * storing the contents of the file.
	 * 
	 * @return An {@link java.io.OutputStream OutputStream} that can be used for
	 *         storing the contensts of the file.
	 * 
	 * @exception IOException
	 *                if an error occurs.
	 */
	public OutputStream getOutputStream() throws IOException
	{
		if (dfos == null)
		{
			File outputFile = getTempFile();
			dfos = new DeferredFileOutputStream(sizeThreshold, outputFile);
		}
		return dfos;
	}


	// --------------------------------------------------------- Public methods


	/**
	 * Returns the {@link java.io.File} object for the <code>FileItem</code>'s
	 * data's temporary location on the disk. Note that for
	 * <code>FileItem</code>s that have their data stored in memory, this
	 * method will return <code>null</code>. When handling large files, you
	 * can use {@link java.io.File#renameTo(java.io.File)} to move the file to
	 * new location without copying the data, if the source and destination
	 * locations reside within the same logical volume.
	 * 
	 * @return The data file, or <code>null</code> if the data is stored in
	 *         memory.
	 */
	public File getStoreLocation()
	{
		return dfos.getFile();
	}


	// ------------------------------------------------------ Protected methods


	/**
	 * Removes the file contents from the temporary storage.
	 */
	protected void finalize()
	{
		File outputFile = dfos.getFile();

		if (outputFile != null && outputFile.exists())
		{
			outputFile.delete();
		}
	}


	/**
	 * Creates and returns a {@link java.io.File File} representing a uniquely
	 * named temporary file in the configured repository path. The lifetime of
	 * the file is tied to the lifetime of the <code>FileItem</code> instance;
	 * the file will be deleted when the instance is garbage collected.
	 * 
	 * @return The {@link java.io.File File} to be used for temporary storage.
	 */
	protected File getTempFile()
	{
		File tempDir = repository;
		if (tempDir == null)
		{
			String systemTmp = null;
			try
			{
				systemTmp = System.getProperty("java.io.tmpdir");
			}
			catch (SecurityException e)
			{
				throw new WicketRuntimeException(
						"Reading property java.io.tmpdir is not allowed"
								+ " for the current security settings. The repository location needs to be"
								+ " set manually, or upgrade permissions to allow reading the tmpdir property.");
			}
			tempDir = new File(systemTmp);
		}

		String fileName = "upload_" + getUniqueId() + ".tmp";

		File f = new File(tempDir, fileName);
		FileCleaner.track(f, this);
		return f;
	}


	// -------------------------------------------------------- Private methods


	/**
	 * Returns an identifier that is unique within the class loader used to load
	 * this class, but does not have random-like apearance.
	 * 
	 * @return A String with the non-random looking instance identifier.
	 */
	private static String getUniqueId()
	{
		int current;
		synchronized (DiskFileItem.class)
		{
			current = counter++;
		}
		String id = Integer.toString(current);

		// If you manage to get more than 100 million of ids, you'll
		// start getting ids longer than 8 characters.
		if (current < 100000000)
		{
			id = ("00000000" + id).substring(id.length());
		}
		return id;
	}

	/**
	 * @see java.lang.Object#toString()
	 */
	public String toString()
	{
		return "name=" + this.getName() + ", StoreLocation="
				+ String.valueOf(this.getStoreLocation()) + ", size=" + this.getSize() + "bytes, "
				+ "isFormField=" + isFormField() + ", FieldName=" + this.getFieldName();
	}

}