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- /*
- * Copyright 2000-2018 Vaadin Ltd.
- *
- * 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 com.vaadin.server;
-
- import java.io.IOException;
-
- import com.vaadin.shared.extension.filedownloader.FileDownloaderState;
- import com.vaadin.ui.AbstractComponent;
-
- /**
- * Extension that starts a download when the extended component is clicked. This
- * is used to overcome two challenges:
- * <ul>
- * <li>Resource should be bound to a component to allow it to be garbage
- * collected when there are no longer any ways of reaching the resource.</li>
- * <li>Download should be started directly when the user clicks e.g. a Button
- * without going through a server-side click listener to avoid triggering
- * security warnings in some browsers.</li>
- * </ul>
- * <p>
- * Please note that the download will be started in an iframe, which means that
- * care should be taken to avoid serving content types that might make the
- * browser attempt to show the content using a plugin instead of downloading it.
- * Connector resources (e.g. {@link FileResource} and {@link ClassResource})
- * will automatically be served using a
- * <code>Content-Type: application/octet-stream</code> header unless
- * {@link #setOverrideContentType(boolean)} has been set to <code>false</code>
- * while files served in other ways, (e.g. {@link ExternalResource} or
- * {@link ThemeResource}) will not automatically get this treatment.
- * </p>
- *
- * @author Vaadin Ltd
- * @since 7.0.0
- */
- public class FileDownloader extends AbstractExtension {
-
- private boolean overrideContentType = true;
-
- /**
- * Creates a new file downloader for the given resource. To use the
- * downloader, you should also {@link #extend(AbstractClientConnector)} the
- * component.
- *
- * @param resource
- * the resource to download when the user clicks the extended
- * component.
- */
- public FileDownloader(Resource resource) {
- if (resource == null) {
- throw new IllegalArgumentException("resource may not be null");
- }
- setResource("dl", resource);
- }
-
- /**
- * Add this extension to the target component.
- *
- * @param target
- * the component to attach this extension to
- */
- public void extend(AbstractComponent target) {
- super.extend(target);
- }
-
- /**
- * Add this extension to the {@code EventTrigger}.
- *
- * @param eventTrigger
- * the trigger to attach this extension to
- * @since 8.4
- */
- public void extend(EventTrigger eventTrigger) {
- super.extend(eventTrigger.getConnector());
- getState().partInformation = eventTrigger.getPartInformation();
- }
-
- /**
- * Gets the resource set for download.
- *
- * @return the resource that will be downloaded if clicking the extended
- * component
- */
- public Resource getFileDownloadResource() {
- return getResource("dl");
- }
-
- /**
- * Sets the resource that is downloaded when the extended component is
- * clicked.
- *
- * @param resource
- * the resource to download
- */
- public void setFileDownloadResource(Resource resource) {
- setResource("dl", resource);
- }
-
- /**
- * Sets whether the content type of served resources should be overridden to
- * <code>application/octet-stream</code> to reduce the risk of a browser
- * plugin choosing to display the resource instead of downloading it. This
- * is by default set to <code>true</code>.
- * <p>
- * Please note that this only affects Connector resources (e.g.
- * {@link FileResource} and {@link ClassResource}) but not other resource
- * types (e.g. {@link ExternalResource} or {@link ThemeResource}).
- * </p>
- *
- * @param overrideContentType
- * <code>true</code> to override the content type if possible;
- * <code>false</code> to use the original content type.
- */
- public void setOverrideContentType(boolean overrideContentType) {
- this.overrideContentType = overrideContentType;
- }
-
- /**
- * Checks whether the content type should be overridden.
- *
- * @return <code>true</code> if the content type will be overridden when
- * possible; <code>false</code> if the original content type will be
- * used.
- * @see #setOverrideContentType(boolean)
- */
- public boolean isOverrideContentType() {
- return overrideContentType;
- }
-
- /**
- * {@inheritDoc}
- *
- * @throws IOException
- * if something goes wrong with the download or the user
- * cancelled the file download process.
- */
- @Override
- public boolean handleConnectorRequest(VaadinRequest request,
- VaadinResponse response, String path) throws IOException {
- if (!path.matches("dl(/.*)?")) {
- // Ignore if it isn't for us
- return false;
- }
- VaadinSession session = getSession();
-
- session.lock();
- DownloadStream stream;
-
- try {
- Resource resource = getFileDownloadResource();
- if (!(resource instanceof ConnectorResource)) {
- return false;
- }
- stream = ((ConnectorResource) resource).getStream();
-
- String contentDisposition = stream
- .getParameter(DownloadStream.CONTENT_DISPOSITION);
- if (contentDisposition == null) {
- contentDisposition = "attachment; " + DownloadStream
- .getContentDispositionFilename(stream.getFileName());
- }
-
- stream.setParameter(DownloadStream.CONTENT_DISPOSITION,
- contentDisposition);
-
- // Content-Type to block eager browser plug-ins from hijacking
- // the file
- if (isOverrideContentType()) {
- stream.setContentType("application/octet-stream;charset=UTF-8");
- }
- } finally {
- session.unlock();
- }
- stream.writeResponse(request, response);
- return true;
- }
-
- @Override
- protected FileDownloaderState getState() {
- return (FileDownloaderState) super.getState();
- }
-
- @Override
- protected FileDownloaderState getState(boolean markAsDirty) {
- return (FileDownloaderState) super.getState(markAsDirty);
- }
-
- }
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