Expose content type resolver api to plugins (#1752)

Expose an api which makes it easy to detect the content type of files. The api is based on the spotter api, but does not expose spotter classes.

Co-authored-by: René Pfeuffer <rene.pfeuffer@cloudogu.com>

scm-webapp/src/main/java/sonia/scm/api/v2/resources/ContentResource.java

@@ -24,7 +24,6 @@
 
 package sonia.scm.api.v2.resources;
 
-import com.github.sdorra.spotter.ContentType;
 import io.swagger.v3.oas.annotations.Operation;
 import io.swagger.v3.oas.annotations.Parameter;
 import io.swagger.v3.oas.annotations.media.Content;
@@ -33,7 +32,8 @@ import io.swagger.v3.oas.annotations.responses.ApiResponse;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 import sonia.scm.NotFoundException;
-import sonia.scm.api.v2.ContentTypeResolver;
+import sonia.scm.io.ContentType;
+import sonia.scm.io.ContentTypeResolver;
 import sonia.scm.repository.NamespaceAndName;
 import sonia.scm.repository.api.RepositoryService;
 import sonia.scm.repository.api.RepositoryServiceFactory;
@@ -61,10 +61,12 @@ public class ContentResource {
   private static final int HEAD_BUFFER_SIZE = 1024;
 
   private final RepositoryServiceFactory serviceFactory;
+  private final ContentTypeResolver contentTypeResolver;
 
   @Inject
-  public ContentResource(RepositoryServiceFactory serviceFactory) {
+  public ContentResource(RepositoryServiceFactory serviceFactory, ContentTypeResolver contentTypeResolver) {
     this.serviceFactory = serviceFactory;
+    this.contentTypeResolver = contentTypeResolver;
   }
 
   /**
@@ -204,10 +206,10 @@ public class ContentResource {
   }
 
   private void appendContentHeader(String path, byte[] head, Response.ResponseBuilder responseBuilder) {
-    ContentType contentType = ContentTypeResolver.resolve(path, head);
+    ContentType contentType = contentTypeResolver.resolve(path, head);
     responseBuilder.header("Content-Type", contentType.getRaw());
     contentType.getLanguage().ifPresent(
-      language -> responseBuilder.header(ProgrammingLanguages.HEADER, ProgrammingLanguages.getValue(language))
+      language -> responseBuilder.header(ProgrammingLanguages.HEADER, language)
     );
   }
 

scm-webapp/src/main/java/sonia/scm/api/v2/resources/DiffResultToDiffResultDtoMapper.java

@@ -24,10 +24,9 @@
 
 package sonia.scm.api.v2.resources;
 
-import com.github.sdorra.spotter.Language;
 import com.google.inject.Inject;
 import de.otto.edison.hal.Links;
-import sonia.scm.api.v2.ContentTypeResolver;
+import sonia.scm.io.ContentTypeResolver;
 import sonia.scm.repository.Repository;
 import sonia.scm.repository.api.DiffFile;
 import sonia.scm.repository.api.DiffLine;
@@ -49,10 +48,12 @@ import static de.otto.edison.hal.Links.linkingTo;
 class DiffResultToDiffResultDtoMapper {
 
   private final ResourceLinks resourceLinks;
+  private final ContentTypeResolver contentTypeResolver;
 
   @Inject
-  DiffResultToDiffResultDtoMapper(ResourceLinks resourceLinks) {
+  DiffResultToDiffResultDtoMapper(ResourceLinks resourceLinks, ContentTypeResolver contentTypeResolver) {
     this.resourceLinks = resourceLinks;
+    this.contentTypeResolver = contentTypeResolver;
   }
 
   public DiffResultDto mapForIncoming(Repository repository, DiffResult result, String source, String target) {
@@ -154,8 +155,8 @@ class DiffResultToDiffResultDtoMapper {
     dto.setOldPath(oldPath);
     dto.setOldRevision(file.getOldRevision());
 
-    Optional<Language> language = ContentTypeResolver.resolve(path).getLanguage();
-    language.ifPresent(value -> dto.setLanguage(ProgrammingLanguages.getValue(value)));
+    Optional<String> language = contentTypeResolver.resolve(path).getLanguage();
+    language.ifPresent(dto::setLanguage);
 
     List<DiffResultDto.HunkDto> hunks = new ArrayList<>();
     for (Hunk hunk : file) {

scm-webapp/src/main/java/sonia/scm/api/v2/resources/ProgrammingLanguages.java

@@ -21,28 +21,13 @@
  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
  * SOFTWARE.
  */
-    
+
 package sonia.scm.api.v2.resources;
 
-import com.github.sdorra.spotter.Language;
-
-import java.util.Optional;
-
 final class ProgrammingLanguages {
 
   static final String HEADER = "X-Programming-Language";
 
-  private static final String DEFAULT = "text";
-
   private ProgrammingLanguages() {
   }
-
-  static String getValue(Language language) {
-    Optional<String> aceMode = language.getAceMode();
-    if (!aceMode.isPresent()) {
-      Optional<String> codemirrorMode = language.getCodemirrorMode();
-      return codemirrorMode.orElse(DEFAULT);
-    }
-    return aceMode.get();
-  }
 }

scm-webapp/src/main/java/sonia/scm/io/DefaultContentType.java

@@ -0,0 +1,66 @@
+/*
+ * MIT License
+ *
+ * Copyright (c) 2020-present Cloudogu GmbH and Contributors
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+
+package sonia.scm.io;
+
+import java.util.Optional;
+
+public class DefaultContentType implements ContentType {
+
+  private static final String DEFAULT_LANG_MODE = "text";
+
+  private final com.github.sdorra.spotter.ContentType contentType;
+
+  DefaultContentType(com.github.sdorra.spotter.ContentType contentType) {
+    this.contentType = contentType;
+  }
+
+  @Override
+  public String getPrimary() {
+    return contentType.getPrimary();
+  }
+
+  @Override
+  public String getSecondary() {
+    return contentType.getSecondary();
+  }
+
+  @Override
+  public String getRaw() {
+    return contentType.getRaw();
+  }
+
+  @Override
+  public boolean isText() {
+    return contentType.isText();
+  }
+
+  @Override
+  public Optional<String> getLanguage() {
+    return contentType.getLanguage().map(language -> {
+      Optional<String> aceMode = language.getAceMode();
+      return aceMode.orElseGet(() -> language.getCodemirrorMode().orElse(DEFAULT_LANG_MODE));
+    });
+  }
+}

scm-webapp/src/main/java/sonia/scm/io/DefaultContentTypeResolver.java

@@ -22,13 +22,12 @@
  * SOFTWARE.
  */
 
-package sonia.scm.api.v2;
+package sonia.scm.io;
 
-import com.github.sdorra.spotter.ContentType;
 import com.github.sdorra.spotter.ContentTypeDetector;
 import com.github.sdorra.spotter.Language;
 
-public final class ContentTypeResolver {
+public final class DefaultContentTypeResolver implements ContentTypeResolver {
 
   private static final ContentTypeDetector PATH_BASED = ContentTypeDetector.builder()
     .defaultPathBased().boost(Language.MARKDOWN)
@@ -38,14 +37,13 @@ public final class ContentTypeResolver {
     .defaultPathAndContentBased().boost(Language.MARKDOWN)
     .bestEffortMatch();
 
-  private ContentTypeResolver() {
+  @Override
+  public DefaultContentType resolve(String path) {
+    return new DefaultContentType(PATH_BASED.detect(path));
   }
 
-  public static ContentType resolve(String path) {
-    return PATH_BASED.detect(path);
-  }
-
-  public static ContentType resolve(String path, byte[] contentPrefix) {
-    return PATH_AND_CONTENT_BASED.detect(path, contentPrefix);
+  @Override
+  public DefaultContentType resolve(String path, byte[] contentPrefix) {
+    return new DefaultContentType(PATH_AND_CONTENT_BASED.detect(path, contentPrefix));
   }
 }

scm-webapp/src/main/java/sonia/scm/lifecycle/modules/ScmServletModule.java

@@ -59,6 +59,8 @@ import sonia.scm.group.GroupManagerProvider;
 import sonia.scm.group.xml.XmlGroupDAO;
 import sonia.scm.initialization.DefaultInitializationFinisher;
 import sonia.scm.initialization.InitializationFinisher;
+import sonia.scm.io.ContentTypeResolver;
+import sonia.scm.io.DefaultContentTypeResolver;
 import sonia.scm.metrics.MeterRegistryProvider;
 import sonia.scm.migration.MigrationDAO;
 import sonia.scm.net.SSLContextProvider;
@@ -290,6 +292,8 @@ class ScmServletModule extends ServletModule {
     bind(IndexQueue.class, DefaultIndexQueue.class);
     bind(SearchEngine.class, LuceneSearchEngine.class);
     bind(IndexLogStore.class, DefaultIndexLogStore.class);
+
+    bind(ContentTypeResolver.class).to(DefaultContentTypeResolver.class);
   }
 
   private <T> void bind(Class<T> clazz, Class<? extends T> defaultImplementation) {