| /* |
| * 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.request.resource; |
| |
| import java.awt.image.BufferedImage; |
| import java.io.ByteArrayOutputStream; |
| import java.io.IOException; |
| import java.time.Instant; |
| import javax.imageio.ImageIO; |
| import jakarta.servlet.http.HttpServletResponse; |
| import org.apache.wicket.WicketRuntimeException; |
| import org.apache.wicket.util.lang.Args; |
| |
| /** |
| * Base class for dynamically generated ImageResources. |
| */ |
| public abstract class DynamicImageResource extends AbstractResource |
| { |
| private static final long serialVersionUID = 1L; |
| |
| /** The image type */ |
| private String format = "png"; |
| |
| /** The last modified time of this resource */ |
| private Instant lastModifiedTime; |
| |
| |
| /** |
| * Construct. |
| */ |
| public DynamicImageResource() |
| { |
| } |
| |
| /** |
| * Creates a dynamic resource from for the given locale |
| * |
| * @param format |
| * The image format ("png", "jpeg", etc) |
| */ |
| public DynamicImageResource(String format) |
| { |
| setFormat(format); |
| } |
| |
| /** |
| * @return Returns the image format. |
| */ |
| public synchronized final String getFormat() |
| { |
| return format; |
| } |
| |
| /** |
| * Sets the format of this resource |
| * |
| * @param format |
| * The format (jpg, png or gif..) |
| */ |
| public synchronized final void setFormat(String format) |
| { |
| Args.notNull(format, "format"); |
| this.format = format; |
| } |
| |
| /** |
| * set the last modified time for this resource. |
| * |
| * @param time |
| */ |
| protected synchronized void setLastModifiedTime(Instant time) |
| { |
| lastModifiedTime = time; |
| } |
| |
| /** |
| * @param image |
| * The image to turn into data |
| * @return The image data for this dynamic image |
| */ |
| protected byte[] toImageData(final BufferedImage image) |
| { |
| try |
| { |
| // Create output stream |
| final ByteArrayOutputStream out = new ByteArrayOutputStream(); |
| |
| // Write image using any matching ImageWriter |
| ImageIO.write(image, format, out); |
| |
| // Return the image data |
| return out.toByteArray(); |
| } |
| catch (IOException e) |
| { |
| throw new WicketRuntimeException("Unable to convert dynamic image to stream", e); |
| } |
| } |
| |
| /** |
| * Get image data for our dynamic image resource. If the subclass regenerates the data, it |
| * should set the {@link DynamicImageResource#setLastModifiedTime(Time)} when it does so. This |
| * ensures that image caching works correctly. |
| * |
| * @param attributes |
| * the context bringing the request, response and the parameters |
| * |
| * @return The image data for this dynamic image. {@code null} means there is no image and 404 |
| * (Not found) response will be return. |
| */ |
| protected abstract byte[] getImageData(Attributes attributes); |
| |
| |
| protected void configureResponse(final ResourceResponse response, final Attributes attributes) |
| { |
| |
| } |
| |
| @Override |
| protected ResourceResponse newResourceResponse(final Attributes attributes) |
| { |
| final ResourceResponse response = new ResourceResponse(); |
| |
| if (lastModifiedTime != null) |
| { |
| response.setLastModified(lastModifiedTime); |
| } |
| else |
| { |
| response.setLastModified(Instant.now()); |
| } |
| |
| if (response.dataNeedsToBeWritten(attributes)) |
| { |
| response.setContentDisposition(ContentDisposition.INLINE); |
| |
| final byte[] imageData = getImageData(attributes); |
| if (imageData == null) |
| { |
| response.setError(HttpServletResponse.SC_NOT_FOUND); |
| } |
| else |
| { |
| response.setContentType("image/" + getFormat()); |
| response.setWriteCallback(new WriteCallback() |
| { |
| @Override |
| public void writeData(final Attributes attributes) |
| { |
| attributes.getResponse().write(imageData); |
| } |
| }); |
| |
| configureResponse(response, attributes); |
| } |
| } |
| |
| return response; |
| } |
| } |