[Issue comixed#27] Add the PageCacheService class and tests.

comixed-services/src/main/java/org/comixed/ComiXedTestContext.java

@@ -0,0 +1,8 @@
+package org.comixed;
+
+import org.springframework.context.annotation.Configuration;
+import org.springframework.test.context.TestPropertySource;
+
+@Configuration
+@TestPropertySource("classpath:application.properties")
+public class ComiXedTestContext {}

comixed-services/src/main/java/org/comixed/service/library/PageCacheService.java

@@ -0,0 +1,79 @@
+/*
+ * ComiXed - A digital comic book library management application.
+ * Copyright (C) 2019, The ComiXed Project
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses>
+ */
+
+package org.comixed.service.library;
+
+import java.io.File;
+import java.io.FileInputStream;
+import java.io.FileOutputStream;
+import java.io.IOException;
+import org.apache.commons.io.IOUtils;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+import org.springframework.beans.factory.annotation.Value;
+import org.springframework.stereotype.Service;
+
+@Service
+public class PageCacheService {
+  protected final Logger logger = LoggerFactory.getLogger(this.getClass());
+
+  @Value("${comixed.images.cache.location}")
+  private String cacheDirectory;
+
+  public byte[] findByHash(final String hash) {
+    this.logger.debug("Searching for cached image: hash={}", hash);
+
+    final File file = this.getFileForHash(hash);
+    if (file.exists() && !file.isDirectory()) {
+      this.logger.debug("Loading cached image content: {} bytes", file.length());
+      try {
+        return IOUtils.readFully(new FileInputStream(file), (int) file.length());
+      } catch (Exception error) {
+        this.logger.error("Failed to load cached image", error);
+      }
+    }
+
+    this.logger.debug("No image in cache");
+    return null;
+  }
+
+  File getFileForHash(final String hash) {
+    if (hash.length() != 32) {
+      return null;
+    }
+
+    final String path =
+        this.cacheDirectory
+            + File.separator
+            + hash.substring(0, 8)
+            + File.separator
+            + hash.substring(8, 16)
+            + File.separator
+            + hash.substring(16, 24)
+            + File.separator
+            + hash.substring(24, 32);
+    return new File(path);
+  }
+
+  public void saveByHash(final String hash, final byte[] content) throws IOException {
+    this.logger.debug("Saving image to cache: hash={}", hash);
+    final File file = this.getFileForHash(hash);
+    file.getParentFile().mkdirs();
+    IOUtils.write(content, new FileOutputStream(file, false));
+  }
+}

comixed-services/src/test/java/org/comixed/service/library/PageCacheServiceTest.java

@@ -0,0 +1,71 @@
+/*
+ * ComiXed - A digital comic book library management application.
+ * Copyright (C) 2019, The ComiXed Project
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses>
+ */
+
+package org.comixed.service.library;
+
+import static junit.framework.TestCase.*;
+
+import java.io.File;
+import java.io.IOException;
+import org.junit.Before;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.test.context.ContextConfiguration;
+import org.springframework.test.context.TestPropertySource;
+import org.springframework.test.context.junit4.SpringRunner;
+
+@RunWith(SpringRunner.class)
+@ContextConfiguration(classes = {PageCacheService.class})
+@TestPropertySource("classpath:application.properties")
+public class PageCacheServiceTest {
+  private static final String TEST_MISSING_PAGE_HASH = "4C6DD238138491B89A3DB9BC6E3A3E2D";
+  private static final String TEST_PAGE_HASH = "D5397C1B6053B093CB133CA3B7081C9E";
+
+  @Autowired private PageCacheService pageCacheService;
+
+  @Before
+  public void setUp() {
+    // clean up any remnant
+    final File file = pageCacheService.getFileForHash(TEST_MISSING_PAGE_HASH);
+    if (file.exists()) {
+      file.delete();
+    }
+  }
+
+  @Test
+  public void testFindByHashNotCached() throws IOException {
+    final byte[] result = pageCacheService.findByHash(TEST_MISSING_PAGE_HASH);
+
+    assertNull(result);
+  }
+
+  @Test
+  public void testFindByHash() throws IOException {
+    final byte[] result = pageCacheService.findByHash(TEST_PAGE_HASH);
+
+    assertNotNull(result);
+  }
+
+  @Test
+  public void testSaveByHash() throws IOException {
+    pageCacheService.saveByHash(TEST_MISSING_PAGE_HASH, TEST_MISSING_PAGE_HASH.getBytes());
+
+    assertTrue(pageCacheService.getFileForHash(TEST_MISSING_PAGE_HASH).exists());
+  }
+}

comixed-services/src/test/resources/application.properties

@@ -33,3 +33,6 @@ comic.entry.loaders[2].bean=filenameEntryLoader
 # Filename entry loaders
 comic.filename-entry.loaders[0].mask=ComicInfo.xml
 comic.filename-entry.loaders[0].bean=comicInfoEntryLoader
+
+# test image caching directory
+comixed.images.cache.location=target/test-classes/image-cache