src/web/java/org/apache/openmeetings/web/util/AjaxDownload.java

/*
 * 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.openmeetings.web.util;

import org.apache.wicket.ajax.AjaxRequestTarget;
import org.apache.wicket.behavior.AbstractAjaxBehavior;
import org.apache.wicket.request.handler.resource.ResourceStreamRequestHandler;
import org.apache.wicket.request.resource.ContentDisposition;
import org.apache.wicket.util.resource.IResourceStream;

/**
 * see: <a href="https://cwiki.apache.org/confluence/display/WICKET/AJAX+update+and+file+download+in+one+blow">
 * https://cwiki.apache.org/confluence/display/WICKET/AJAX+update+and+file+download+in+one+blow</href>
 * 
 */
public class AjaxDownload extends AbstractAjaxBehavior {
	private static final long serialVersionUID = 1L;

	private boolean addAntiCache;

	private String fileName;
	private IResourceStream resourceStream;

	public AjaxDownload() {
		this(true);
	}

	public AjaxDownload(boolean addAntiCache) {
		super();
		this.addAntiCache = addAntiCache;
	}

	/**
	 * Call this method to initiate the download.
	 */
	public void initiate(AjaxRequestTarget target) {
		String url = getCallbackUrl().toString();

		if (addAntiCache) {
			url = url + (url.contains("?") ? "&" : "?");
			url = url + "antiCache=" + System.currentTimeMillis();
		}

		// the timeout is needed to let Wicket release the channel
		target.appendJavaScript("setTimeout(\"window.location.href='" + url + "'\", 100);");
	}

	public void onRequest() {
		ResourceStreamRequestHandler handler = new ResourceStreamRequestHandler(getResourceStream(), getFileName());
		handler.setContentDisposition(getContentDisposition());
		getComponent().getRequestCycle().scheduleRequestHandlerAfterCurrent(handler);
	}

	protected ContentDisposition getContentDisposition() {
		return ContentDisposition.ATTACHMENT;
	}
	/**
	 * Override this method for a file name which will let the browser prompt
	 * with a save/open dialog.
	 * 
	 * @see ResourceStreamRequestTarget#getFileName()
	 */
	protected String getFileName() {
		return this.fileName;
	}

	public void setFileName(String fileName) {
		this.fileName = fileName;
	}

	/**
	 * Hook method providing the actual resource stream.
	 */
	protected IResourceStream getResourceStream() {
		return resourceStream;

	}

	public void setResourceStream(IResourceStream resourceStream) {
		this.resourceStream = resourceStream;
	}

}