redirect check and improve logging

src/main/java/org/codelibs/fess/thumbnail/impl/BaseThumbnailGenerator.java

@@ -57,6 +57,8 @@ public abstract class BaseThumbnailGenerator implements ThumbnailGenerator {
 
     protected String name;
 
+    protected int maxRedirectCount = 10;
+
     public void addCondition(final String key, final String regex) {
         conditionMap.put(key, regex);
     }
@@ -173,30 +175,43 @@ public abstract class BaseThumbnailGenerator implements ThumbnailGenerator {
     }
 
     protected boolean process(final String id, final Predicate<ResponseData> consumer) {
-        return process(id, (configId, url) -> {
-            final CrawlingConfigHelper crawlingConfigHelper = ComponentUtil.getCrawlingConfigHelper();
-            CrawlingConfig config = crawlingConfigHelper.getCrawlingConfig(configId);
-            if (config == null) {
-                throw new ThumbnailGenerationException("No CrawlingConfig: " + configId);
-            }
-            final CrawlerClientFactory crawlerClientFactory = ComponentUtil.getComponent(CrawlerClientFactory.class);
-            config.initializeClientFactory(crawlerClientFactory);
-            final CrawlerClient client = crawlerClientFactory.getClient(url);
-            if (client == null) {
-                throw new ThumbnailGenerationException("No CrawlerClient: " + configId + ", url: " + url);
-            }
-            try (final ResponseData responseData = client.execute(RequestDataBuilder.newRequestData().get().url(url).build())) {
-                return consumer.test(responseData);
-            } catch (final CrawlingAccessException e) {
-                if (logger.isDebugEnabled()) {
-                    throw new ThumbnailGenerationException("Failed to process a thumbnail content: " + url, e);
-                } else {
-                    throw new ThumbnailGenerationException(e.getMessage());
-                }
-            } catch (final Exception e) {
-                throw new ThumbnailGenerationException("Failed to process a thumbnail content: " + url, e);
-            }
-        });
+        return process(id,
+                (configId, url) -> {
+                    final CrawlingConfigHelper crawlingConfigHelper = ComponentUtil.getCrawlingConfigHelper();
+                    CrawlingConfig config = crawlingConfigHelper.getCrawlingConfig(configId);
+                    if (config == null) {
+                        throw new ThumbnailGenerationException("No CrawlingConfig: " + configId);
+                    }
+                    final CrawlerClientFactory crawlerClientFactory = ComponentUtil.getComponent(CrawlerClientFactory.class);
+                    config.initializeClientFactory(crawlerClientFactory);
+                    final CrawlerClient client = crawlerClientFactory.getClient(url);
+                    if (client == null) {
+                        throw new ThumbnailGenerationException("No CrawlerClient: " + configId + ", url: " + url);
+                    }
+                    String u = url;
+                    for (int i = 0; i < maxRedirectCount; i++) {
+                        try (final ResponseData responseData = client.execute(RequestDataBuilder.newRequestData().get().url(u).build())) {
+                            if (StringUtil.isNotBlank(responseData.getRedirectLocation())) {
+                                u = responseData.getRedirectLocation();
+                                continue;
+                            }
+                            if (StringUtil.isBlank(responseData.getUrl())) {
+                                throw new ThumbnailGenerationException("Failed to process a thumbnail content: " + url
+                                        + " (Response URL is empty)");
+                            }
+                            return consumer.test(responseData);
+                        } catch (final CrawlingAccessException e) {
+                            if (logger.isDebugEnabled()) {
+                                throw new ThumbnailGenerationException("Failed to process a thumbnail content: " + url, e);
+                            } else {
+                                throw new ThumbnailGenerationException(e.getMessage());
+                            }
+                        } catch (final Exception e) {
+                            throw new ThumbnailGenerationException("Failed to process a thumbnail content: " + url, e);
+                        }
+                    }
+                    throw new ThumbnailGenerationException("Failed to process a thumbnail content: " + url + " (Redirect Loop)");
+                });
     }
 
     public void setGeneratorList(final List<String> generatorList) {
@@ -212,4 +227,8 @@ public abstract class BaseThumbnailGenerator implements ThumbnailGenerator {
         this.name = name;
     }
 
+    public void setMaxRedirectCount(int maxRedirectCount) {
+        this.maxRedirectCount = maxRedirectCount;
+    }
+
 }

src/main/java/org/codelibs/fess/thumbnail/impl/HtmlTagBasedGenerator.java

@@ -97,15 +97,15 @@ public class HtmlTagBasedGenerator extends BaseThumbnailGenerator {
                             created = true;
                             break;
                         case FAILED:
-                            logger.warn("Failed to create thumbnail: " + thumbnailId);
+                            logger.warn("Failed to create thumbnail: " + thumbnailId + " -> " + responseData.getUrl());
                             break;
                         case INVALID_SIZE:
                             if (logger.isDebugEnabled()) {
-                                logger.debug("Invalid thumbnail size: " + thumbnailId);
+                                logger.debug("Invalid thumbnail size: " + thumbnailId + " -> " + responseData.getUrl());
                             }
                             break;
                         default:
-                            logger.error("Unknown thumbnail result: " + thumbnailId);
+                            logger.error("Unknown thumbnail result: " + thumbnailId + " -> " + responseData.getUrl());
                             break;
                         }
                     } catch (final Throwable t) {