DynamicMediaPath.java

  1. /*
  2.  * #%L
  3.  * wcm.io
  4.  * %%
  5.  * Copyright (C) 2020 wcm.io
  6.  * %%
  7.  * Licensed under the Apache License, Version 2.0 (the "License");
  8.  * you may not use this file except in compliance with the License.
  9.  * You may obtain a copy of the License at
  10.  *
  11.  *      http://www.apache.org/licenses/LICENSE-2.0
  12.  *
  13.  * Unless required by applicable law or agreed to in writing, software
  14.  * distributed under the License is distributed on an "AS IS" BASIS,
  15.  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  16.  * See the License for the specific language governing permissions and
  17.  * limitations under the License.
  18.  * #L%
  19.  */
  20. package io.wcm.handler.mediasource.dam.impl.dynamicmedia;

  22. import java.net.URLEncoder;
  23. import java.nio.charset.StandardCharsets;

  25. import org.apache.commons.lang3.StringUtils;
  26. import org.jetbrains.annotations.NotNull;
  27. import org.jetbrains.annotations.Nullable;
  28. import org.slf4j.Logger;
  29. import org.slf4j.LoggerFactory;

  31. import io.wcm.handler.media.CropDimension;
  32. import io.wcm.handler.media.Dimension;
  33. import io.wcm.handler.media.format.Ratio;
  34. import io.wcm.handler.media.impl.ImageQualityPercentage;
  35. import io.wcm.handler.mediasource.dam.impl.DamContext;
  36. import io.wcm.wcm.commons.contenttype.ContentType;

  38. /**
  39.  * Build part of dynamic media/scene7 URL to render renditions.
  40.  */
  41. public final class DynamicMediaPath {

  43.   /**
  44.    * Fixed path part for dynamic media image serving API for serving images.
  45.    */
  46.   @SuppressWarnings("java:S1075") // not a file path
  47.   private static final String IMAGE_SERVER_PATH = "/is/image/";

  49.   /**
  50.    * Fixed path part for dynamic media image serving API for serving static content.
  51.    */
  52.   @SuppressWarnings("java:S1075") // not a file path
  53.   private static final String CONTENT_SERVER_PATH = "/is/content/";

  55.   /**
  56.    * Suffix is appended to static content dynamic media URLs that should be served with
  57.    * Content-Disposition: attachment header.
  58.    * This is configured via a custom ruleset, see https://wcm.io/handler/media/dynamic-media.html
  59.    */
  60.   public static final String DOWNLOAD_SUFFIX = "?cdh=attachment";

  62.   private static final Logger log = LoggerFactory.getLogger(DynamicMediaPath.class);

  64.   private DynamicMediaPath() {
  65.     // static methods only
  66.   }

  68.   /**
  69.    * Build media path for serving static content via dynamic media/scene7.
  70.    * @param damContext DAM context objects
  71.    * @param contentDispositionAttachment Whether to send content disposition: attachment header for downloads
  72.    * @return Media path
  73.    */
  74.   public static @NotNull String buildContent(@NotNull DamContext damContext, boolean contentDispositionAttachment) {
  75.     StringBuilder result = new StringBuilder();
  76.     result.append(CONTENT_SERVER_PATH).append(encodeDynamicMediaObject(damContext));
  77.     if (contentDispositionAttachment) {
  78.       result.append(DOWNLOAD_SUFFIX);
  79.     }
  80.     return result.toString();
  81.   }

  83.   /**
  84.    * Build media path for rendering image via dynamic media/scene7.
  85.    * @param damContext DAM context objects
  86.    * @return Media path
  87.    */
  88.   public static @NotNull String buildImage(@NotNull DamContext damContext) {
  89.     return IMAGE_SERVER_PATH + encodeDynamicMediaObject(damContext);
  90.   }

  92.   /**
  93.    * Build media path for rendering image with dynamic media/scene7.
  94.    * @param damContext DAM context objects
  95.    * @param width Width
  96.    * @param height Height
  97.    * @return Media path
  98.    */
  99.   public static @Nullable String buildImage(@NotNull DamContext damContext, long width, long height) {
  100.     return buildImage(damContext, width, height, null, null);
  101.   }

  103.   /**
  104.    * Build media path for rendering image with dynamic media/scene7.
  105.    * @param damContext DAM context objects
  106.    * @param width Width
  107.    * @param height Height
  108.    * @param cropDimension Crop dimension
  109.    * @param rotation Rotation
  110.    * @return Media path
  111.    */
  112.   public static @Nullable String buildImage(@NotNull DamContext damContext, long width, long height,
  113.       @Nullable CropDimension cropDimension, @Nullable Integer rotation) {
  114.     Dimension dimension = calcWidthHeight(damContext, width, height);

  116.     StringBuilder result = new StringBuilder();
  117.     result.append(IMAGE_SERVER_PATH).append(encodeDynamicMediaObject(damContext));

  119.     // check for smart cropping when no cropping was applied by default, or auto-crop is enabled
  120.     if (SmartCrop.canApply(cropDimension, rotation)) {
  121.       // check for matching image profile and use predefined cropping preset if match found
  122.       NamedDimension smartCropDef = SmartCrop.getDimensionForWidthHeight(damContext.getImageProfile(), width, height);
  123.       if (smartCropDef != null) {
  124.         if (damContext.isDynamicMediaValidateSmartCropRenditionSizes()
  125.             && !SmartCrop.isMatchingSize(damContext.getAsset(), damContext.getResourceResolver(), smartCropDef, width, height)) {
  126.           // smart crop should be applied, but selected area is too small, treat as invalid
  127.           logResult(damContext, "<too small for " + width + "x" + height + ">");
  128.           return null;
  129.         }
  130.         result.append("%3A").append(smartCropDef.getName()).append("?");
  131.         appendWidthHeigtFormatQuality(result, dimension, damContext);
  132.         logResult(damContext, result);
  133.         return result.toString();
  134.       }
  135.     }

  137.     result.append("?");
  138.     if (cropDimension != null) {
  139.       result.append("crop=").append(cropDimension.getCropStringWidthHeight()).append("&");
  140.     }
  141.     if (rotation != null) {
  142.       result.append("rotate=").append(rotation).append("&");
  143.     }
  144.     appendWidthHeigtFormatQuality(result, dimension, damContext);
  145.     logResult(damContext, result);
  146.     return result.toString();
  147.   }

  149.   private static void appendWidthHeigtFormatQuality(@NotNull StringBuilder result, @NotNull Dimension dimension, @NotNull DamContext damContext) {
  150.     result.append("wid=").append(dimension.getWidth()).append("&")
  151.         .append("hei=").append(dimension.getHeight()).append("&")
  152.         // cropping/width/height is pre-calculated to fit with original ratio, make sure there are no 1px background lines visible
  153.         .append("fit=stretch");
  154.     if (isPNG(damContext)) {
  155.       // if original image is PNG image, make sure alpha channel is preserved
  156.       result.append("&fmt=png-alpha");
  157.     }
  158.     else if (damContext.isDynamicMediaSetImageQuality()) {
  159.       // it not PNG lossy format is used, apply image quality setting
  160.       result.append("&qlt=").append(ImageQualityPercentage.getAsInteger(damContext.getMediaArgs(), damContext.getMediaHandlerConfig()));
  161.     }
  162.   }

  164.   private static void logResult(@NotNull DamContext damContext, @NotNull CharSequence result) {
  165.     if (log.isTraceEnabled()) {
  166.       log.trace("Build dynamic media path for {}: {}", damContext.getAsset().getPath(), result);
  167.     }
  168.   }

  170.   /**
  171.    * Checks if width or height is bigger than the allowed max. width/height.
  172.    * Reduces both to the max limit keeping aspect ration is required.
  173.    * @param width With
  174.    * @param height Height
  175.    * @return Dimension with capped width/height
  176.    */
  177.   private static Dimension calcWidthHeight(@NotNull DamContext damContext, long width, long height) {
  178.     Dimension sizeLimit = damContext.getDynamicMediaImageSizeLimit();
  179.     if (width > sizeLimit.getWidth()) {
  180.       double ratio = Ratio.get(width, height);
  181.       long newWidth = sizeLimit.getWidth();
  182.       long newHeight = Math.round(newWidth / ratio);
  183.       return calcWidthHeight(damContext, newWidth, newHeight);
  184.     }
  185.     if (height > sizeLimit.getHeight()) {
  186.       double ratio = Ratio.get(width, height);
  187.       long newHeight = sizeLimit.getHeight();
  188.       long newWidth = Math.round(newHeight * ratio);
  189.       return new Dimension(newWidth, newHeight);
  190.     }
  191.     return new Dimension(width, height);
  192.   }

  194.   /**
  195.    * Splits dynamic media folder and file name and URL-encodes them separately (may contain spaces or special chars).
  196.    * @param damContext DAM context
  197.    * @return Encoded path
  198.    */
  199.   private static String encodeDynamicMediaObject(@NotNull DamContext damContext) {
  200.     String[] pathParts = StringUtils.split(damContext.getDynamicMediaObject(), "/");
  201.     for (int i = 0; i < pathParts.length; i++) {
  202.       pathParts[i] = URLEncoder.encode(pathParts[i], StandardCharsets.UTF_8);
  203.       // replace "+" with %20 in URL paths
  204.       pathParts[i] = StringUtils.replace(pathParts[i], "+", "%20");
  205.     }
  206.     return StringUtils.join(pathParts, "/");
  207.   }

  209.   private static boolean isPNG(@NotNull DamContext damContext) {
  210.     return StringUtils.equals(damContext.getAsset().getMimeType(), ContentType.PNG);
  211.   }

  213. }
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