/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You 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 org.apache.wicket.markup.html.link;
import java.io.File;
import org.apache.wicket.model.IModel;
import org.apache.wicket.model.Model;
import org.apache.wicket.request.IRequestCycle;
import org.apache.wicket.request.handler.resource.ResourceStreamRequestHandler;
import org.apache.wicket.request.resource.ContentDisposition;
import org.apache.wicket.util.file.Files;
import org.apache.wicket.util.lang.Args;
import org.apache.wicket.util.resource.FileResourceStream;
import org.apache.wicket.util.resource.IResourceStream;
import org.apache.wicket.util.string.Strings;
import org.apache.wicket.util.time.Duration;
/**
* A link that streams a file to the client. When clicked this link will prompt the save as dialog
* in the browser.
*
* NOTICE that this link will lock the page. That means only one link from the page can be
* downloaded at a time, and also while the download happens the page cannot be accessed by other
* threads. If you need to stream multiple files concurrently without blocking then you should use
* shared resources or a non-wicket servlet.
*
* @author Igor Vaynberg (ivaynberg)
*/
public class DownloadLink extends Link<File>
{
private static final long serialVersionUID = 1L;
/**
* The file name that will be used in the response headers.<br/>
* Optional. If omitted the name of the provided file will be used.
*/
private IModel<String> fileNameModel;
/**
* A flag indicating whether the file should be deleted after download.
*/
private boolean deleteAfter;
/**
* The duration for which the file resource should be cached by the browser.
* <p>
* By default is {@code null} and
* {@link org.apache.wicket.settings.ResourceSettings#getDefaultCacheDuration()} is used.
* </p>
*/
private Duration cacheDuration;
/**
* Constructor. File name used will be the result of <code>file.getName()</code>
*
* @param id
* component id
* @param file
* file to stream to client
*/
public DownloadLink(String id, File file)
{
this(id, new Model<File>(Args.notNull(file, "file")));
}
/**
* Constructor. File name used will be the result of <code>file.getName()</code>
*
* @param id
* component id
* @param model
* model that contains the file object
*/
public DownloadLink(String id, IModel<File> model)
{
this(id, model, (IModel<String>)null);
}
/**
* Constructor. File name used will be the result of <code>file.getName()</code>
*
* @param id
* component id
* @param model
* model that contains the file object
* @param fileName
* name of the file
*/
public DownloadLink(String id, IModel<File> model, String fileName)
{
this(id, model, Model.of(fileName));
}
/**
* Constructor
*
* @param id
* component id
* @param file
* file to stream to client
* @param fileName
* name of the file
*/
public DownloadLink(String id, File file, String fileName)
{
this(id, Model.of(Args.notNull(file, "file")), Model.of(fileName));
}
/**
* Constructor. File name used will be the result of <code>file.getName()</code>
*
* @param id
* component id
* @param fileModel
* model that contains the file object
* @param fileNameModel
* model that provides the file name to use in the response headers
*/
public DownloadLink(String id, IModel<File> fileModel, IModel<String> fileNameModel)
{
super(id, fileModel);
this.fileNameModel = wrap(fileNameModel);
}
@Override
public void detachModels()
{
super.detachModels();
if (fileNameModel != null)
{
fileNameModel.detach();
}
}
@Override
public void onClick()
{
final File file = getModelObject();
if (file == null)
{
throw new IllegalStateException(getClass().getName() +
" failed to retrieve a File object from model");
}
String fileName = fileNameModel != null ? fileNameModel.getObject() : null;
if (Strings.isEmpty(fileName))
{
fileName = file.getName();
}
IResourceStream resourceStream = new FileResourceStream(
new org.apache.wicket.util.file.File(file));
getRequestCycle().scheduleRequestHandlerAfterCurrent(
new ResourceStreamRequestHandler(resourceStream)
{
@Override
public void respond(IRequestCycle requestCycle)
{
super.respond(requestCycle);
if (deleteAfter)
{
Files.remove(file);
}
}
}.setFileName(fileName)
.setContentDisposition(ContentDisposition.ATTACHMENT)
.setCacheDuration(cacheDuration));
}
/**
* USE THIS METHOD WITH CAUTION!
*
* If true, the file will be deleted! The recommended way to use this setting, is to set this
* DownloadLink object's model with a LoadableDetachableModel instance and the resulting file
* being generated in a temporary folder.
*
* @param deleteAfter
* true to delete file after download succeeds
* @return this component
*/
public final DownloadLink setDeleteAfterDownload(boolean deleteAfter)
{
this.deleteAfter = deleteAfter;
return this;
}
/**
* Sets the duration for which the file resource should be cached by the client.
*
* @param duration
* the duration to cache
* @return this component.
*/
public DownloadLink setCacheDuration(final Duration duration)
{
cacheDuration = duration;
return this;
}
}