Refactor theme sacn (#869)

* Provide theme collector

* Refactor theme property scan

* Refactor ThemePropertyScanner

* Rectify return type

* Change activated theme fetch strategy

* Refactor theme service

* Reformat unexpected codes

* Remove unused imports

Co-authored-by: johnniang <johnniang@fastmail.com>

src/main/java/run/halo/app/cache/AbstractStringCacheStore.java

@@ -25,7 +25,7 @@ public abstract class AbstractStringCacheStore extends AbstractCacheStore<String
             cacheWrapper = JsonUtils.jsonToObject(json, CacheWrapper.class);
         } catch (IOException e) {
             e.printStackTrace();
-            log.debug("erro json to wrapper value bytes: [{}]", json, e);
+            log.debug("Failed to convert json to wrapper value bytes: [{}]", json, e);
         }
         return Optional.ofNullable(cacheWrapper);
     }

src/main/java/run/halo/app/controller/admin/api/ThemeController.java

@@ -15,7 +15,6 @@ import run.halo.app.service.ThemeSettingService;
 
 import java.util.List;
 import java.util.Map;
-import java.util.Set;
 
 /**
  * Theme controller.
@@ -45,7 +44,7 @@ public class ThemeController {
 
     @GetMapping
     @ApiOperation("Lists all themes")
-    public Set<ThemeProperty> listAll() {
+    public List<ThemeProperty> listAll() {
         return themeService.getThemes();
     }
 
@@ -91,13 +90,13 @@ public class ThemeController {
 
     @GetMapping("activation/template/custom/sheet")
     @ApiOperation("Gets custom sheet templates")
-    public Set<String> customSheetTemplate() {
+    public List<String> customSheetTemplate() {
         return themeService.listCustomTemplates(themeService.getActivatedThemeId(), ThemeService.CUSTOM_SHEET_PREFIX);
     }
 
     @GetMapping("activation/template/custom/post")
     @ApiOperation("Gets custom post templates")
-    public Set<String> customPostTemplate() {
+    public List<String> customPostTemplate() {
         return themeService.listCustomTemplates(themeService.getActivatedThemeId(), ThemeService.CUSTOM_POST_PREFIX);
     }
 

src/main/java/run/halo/app/controller/content/ContentContentController.java

@@ -83,19 +83,23 @@ public class ContentContentController {
                           Model model) {
         if (optionService.getArchivesPrefix().equals(prefix)) {
             return postModel.archives(1, model);
-        } else if (optionService.getCategoriesPrefix().equals(prefix)) {
-            return categoryModel.list(model);
-        } else if (optionService.getTagsPrefix().equals(prefix)) {
-            return tagModel.list(model);
-        } else if (optionService.getJournalsPrefix().equals(prefix)) {
-            return journalModel.list(1, model);
-        } else if (optionService.getPhotosPrefix().equals(prefix)) {
-            return photoModel.list(1, model);
-        } else if (optionService.getLinksPrefix().equals(prefix)) {
-            return linkModel.list(model);
-        } else {
-            throw new NotFoundException("Not Found");
         }
+        if (optionService.getCategoriesPrefix().equals(prefix)) {
+            return categoryModel.list(model);
+        }
+        if (optionService.getTagsPrefix().equals(prefix)) {
+            return tagModel.list(model);
+        }
+        if (optionService.getJournalsPrefix().equals(prefix)) {
+            return journalModel.list(1, model);
+        }
+        if (optionService.getPhotosPrefix().equals(prefix)) {
+            return photoModel.list(1, model);
+        }
+        if (optionService.getLinksPrefix().equals(prefix)) {
+            return linkModel.list(model);
+        }
+        return null;
     }
 
     @GetMapping("{prefix}/page/{page:\\d+}")

src/main/java/run/halo/app/controller/core/CommonController.java

@@ -26,6 +26,8 @@ import javax.servlet.http.HttpServletResponse;
 import java.util.Collections;
 import java.util.Map;
 
+import static run.halo.app.model.support.HaloConst.DEFAULT_ERROR_PATH;
+
 /**
  * Error page Controller
  *
@@ -43,16 +45,12 @@ public class CommonController extends AbstractErrorController {
 
     private static final String ERROR_TEMPLATE = "error.ftl";
 
-    private static final String DEFAULT_ERROR_PATH = "common/error/error";
-
     private static final String COULD_NOT_RESOLVE_VIEW_WITH_NAME_PREFIX = "Could not resolve view with name '";
 
     private final ThemeService themeService;
 
     private final ErrorProperties errorProperties;
 
-    private final ErrorAttributes errorAttributes;
-
     private final OptionService optionService;
 
     public CommonController(ThemeService themeService,
@@ -61,7 +59,6 @@ public class CommonController extends AbstractErrorController {
                             OptionService optionService) {
         super(errorAttributes);
         this.themeService = themeService;
-        this.errorAttributes = errorAttributes;
         this.errorProperties = serverProperties.getError();
         this.optionService = optionService;
     }
@@ -166,9 +163,9 @@ public class CommonController extends AbstractErrorController {
         }
 
         Throwable throwable = (Throwable) throwableObject;
-        log.error("Captured an exception", throwable);
 
         if (throwable instanceof NestedServletException) {
+            log.error("Captured an exception", throwable);
             Throwable rootCause = ((NestedServletException) throwable).getRootCause();
             if (rootCause instanceof AbstractHaloException) {
                 AbstractHaloException haloException = (AbstractHaloException) rootCause;
@@ -177,6 +174,7 @@ public class CommonController extends AbstractErrorController {
                 request.setAttribute("javax.servlet.error.message", haloException.getMessage());
             }
         } else if (StringUtils.startsWithIgnoreCase(throwable.getMessage(), COULD_NOT_RESOLVE_VIEW_WITH_NAME_PREFIX)) {
+            log.debug("Captured an exception", throwable);
             request.setAttribute("javax.servlet.error.status_code", HttpStatus.NOT_FOUND.value());
 
             NotFoundException viewNotFound = new NotFoundException("该路径没有对应的模板");

src/main/java/run/halo/app/handler/theme/config/impl/YamlThemePropertyResolver.java

@@ -1,12 +1,11 @@
 package run.halo.app.handler.theme.config.impl;
 
-import com.fasterxml.jackson.databind.DeserializationFeature;
+import org.springframework.lang.NonNull;
-import com.fasterxml.jackson.databind.ObjectMapper;
-import com.fasterxml.jackson.dataformat.yaml.YAMLFactory;
 import org.springframework.stereotype.Service;
 import org.springframework.util.Assert;
 import run.halo.app.handler.theme.config.ThemePropertyResolver;
 import run.halo.app.handler.theme.config.support.ThemeProperty;
+import run.halo.app.theme.YamlResolver;
 
 import java.io.IOException;
 
@@ -19,17 +18,11 @@ import java.io.IOException;
 @Service
 public class YamlThemePropertyResolver implements ThemePropertyResolver {
 
-    private final ObjectMapper yamlMapper;
-
-    public YamlThemePropertyResolver() {
-        yamlMapper = new ObjectMapper(new YAMLFactory());
-        yamlMapper.configure(DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES, false);
-    }
-
     @Override
-    public ThemeProperty resolve(String content) throws IOException {
+    @NonNull
+    public ThemeProperty resolve(@NonNull String content) throws IOException {
         Assert.hasText(content, "Theme file content must not be null");
 
-        return yamlMapper.readValue(content, ThemeProperty.class);
+        return YamlResolver.INSTANCE.getYamlMapper().readValue(content, ThemeProperty.class);
     }
 }

src/main/java/run/halo/app/listener/StartedListener.java

@@ -65,7 +65,7 @@ public class StartedListener implements ApplicationListener<ApplicationStartedEv
         try {
             this.migrate();
         } catch (SQLException e) {
-            e.printStackTrace();
+            log.error("Failed to migrate database!", e);
         }
         this.initThemes();
         this.initDirectory();

src/main/java/run/halo/app/listener/freemarker/FreemarkerConfigAwareListener.java

@@ -12,7 +12,6 @@ import run.halo.app.event.options.OptionUpdatedEvent;
 import run.halo.app.event.theme.ThemeActivatedEvent;
 import run.halo.app.event.theme.ThemeUpdatedEvent;
 import run.halo.app.event.user.UserUpdatedEvent;
-import run.halo.app.handler.theme.config.support.ThemeProperty;
 import run.halo.app.model.properties.BlogProperties;
 import run.halo.app.model.properties.SeoProperties;
 import run.halo.app.model.support.HaloConst;
@@ -101,7 +100,8 @@ public class FreemarkerConfigAwareListener {
 
     private void loadOptionsConfig() throws TemplateModelException {
 
-        String context = optionService.isEnabledAbsolutePath() ? optionService.getBlogBaseUrl() + "/" : "/";
+        final String blogBaseUrl = optionService.getBlogBaseUrl();
+        final String context = optionService.isEnabledAbsolutePath() ? blogBaseUrl + "/" : "/";
 
         configuration.setSharedVariable("options", optionService.listOptions());
         configuration.setSharedVariable("context", context);
@@ -109,15 +109,15 @@ public class FreemarkerConfigAwareListener {
 
         configuration.setSharedVariable("globalAbsolutePathEnabled", optionService.isEnabledAbsolutePath());
         configuration.setSharedVariable("blog_title", optionService.getBlogTitle());
-        configuration.setSharedVariable("blog_url", optionService.getBlogBaseUrl());
+        configuration.setSharedVariable("blog_url", blogBaseUrl);
         configuration.setSharedVariable("blog_logo", optionService.getByPropertyOrDefault(BlogProperties.BLOG_LOGO, String.class, BlogProperties.BLOG_LOGO.defaultValue()));
         configuration.setSharedVariable("seo_keywords", optionService.getByPropertyOrDefault(SeoProperties.KEYWORDS, String.class, SeoProperties.KEYWORDS.defaultValue()));
         configuration.setSharedVariable("seo_description", optionService.getByPropertyOrDefault(SeoProperties.DESCRIPTION, String.class, SeoProperties.DESCRIPTION.defaultValue()));
 
-        configuration.setSharedVariable("rss_url", optionService.getBlogBaseUrl() + "/rss.xml");
+        configuration.setSharedVariable("rss_url", blogBaseUrl + "/rss.xml");
-        configuration.setSharedVariable("atom_url", optionService.getBlogBaseUrl() + "/atom.xml");
+        configuration.setSharedVariable("atom_url", blogBaseUrl + "/atom.xml");
-        configuration.setSharedVariable("sitemap_xml_url", optionService.getBlogBaseUrl() + "/sitemap.xml");
+        configuration.setSharedVariable("sitemap_xml_url", blogBaseUrl + "/sitemap.xml");
-        configuration.setSharedVariable("sitemap_html_url", optionService.getBlogBaseUrl() + "/sitemap.html");
+        configuration.setSharedVariable("sitemap_html_url", blogBaseUrl + "/sitemap.html");
         configuration.setSharedVariable("links_url", context + optionService.getLinksPrefix());
         configuration.setSharedVariable("photos_url", context + optionService.getPhotosPrefix());
         configuration.setSharedVariable("journals_url", context + optionService.getJournalsPrefix());
@@ -128,13 +128,11 @@ public class FreemarkerConfigAwareListener {
         log.debug("Loaded options");
     }
 
-    private void loadThemeConfig() throws TemplateModelException {
+    private void loadThemeConfig() {
-
         // Get current activated theme.
-        ThemeProperty activatedTheme = themeService.getActivatedTheme();
+        themeService.fetchActivatedTheme().ifPresent(activatedTheme -> {
-
             String themeBasePath = (optionService.isEnabledAbsolutePath() ? optionService.getBlogBaseUrl() : "") + "/themes/" + activatedTheme.getFolderName();
-
+            try {
                 configuration.setSharedVariable("theme", activatedTheme);
 
                 // TODO: It will be removed in future versions
@@ -144,5 +142,10 @@ public class FreemarkerConfigAwareListener {
 
                 configuration.setSharedVariable("settings", themeSettingService.listAsMapBy(themeService.getActivatedThemeId()));
                 log.debug("Loaded theme and settings");
+            } catch (TemplateModelException e) {
+                log.error("Failed to set shared variable!", e);
+            }
+        });
+
     }
 }

src/main/java/run/halo/app/model/support/HaloConst.java

@@ -50,6 +50,11 @@ public class HaloConst {
      */
     public final static String DEFAULT_THEME_ID = "caicai_anatole";
 
+    /**
+     * Default error path.
+     */
+    public static final String DEFAULT_ERROR_PATH = "common/error/error";
+
     /**
      * Path separator.
      */

src/main/java/run/halo/app/service/ThemeService.java

@@ -11,7 +11,6 @@ import java.io.IOException;
 import java.nio.file.Path;
 import java.util.List;
 import java.util.Optional;
-import java.util.Set;
 
 /**
  * Theme service interface.
@@ -30,6 +29,7 @@ public interface ThemeService {
     /**
      * Theme property file name.
      */
+    @Deprecated
     String[] THEME_PROPERTY_FILE_NAMES = {"theme.yaml", "theme.yml"};
 
 
@@ -56,6 +56,7 @@ public interface ThemeService {
     /**
      * Theme screenshots name.
      */
+    @Deprecated
     String THEME_SCREENSHOTS_NAME = "screenshot";
 
 
@@ -101,6 +102,7 @@ public interface ThemeService {
      * @return theme property
      */
     @NonNull
+    @Deprecated
     ThemeProperty getThemeOfNonNullBy(@NonNull String themeId);
 
     /**
@@ -110,7 +112,7 @@ public interface ThemeService {
      * @return a optional theme property
      */
     @NonNull
-    Optional<ThemeProperty> getThemeBy(@Nullable String themeId);
+    Optional<ThemeProperty> fetchThemePropertyBy(@Nullable String themeId);
 
     /**
      * Gets all themes
@@ -118,15 +120,7 @@ public interface ThemeService {
      * @return set of themes
      */
     @NonNull
-    Set<ThemeProperty> getThemes();
+    List<ThemeProperty> getThemes();
-
-    /**
-     * Lists theme folder by absolute path.
-     *
-     * @param absolutePath absolutePath
-     * @return List<ThemeFile>
-     */
-    List<ThemeFile> listThemeFolder(@NonNull String absolutePath);
 
     /**
      * Lists theme folder by theme name.
@@ -134,6 +128,7 @@ public interface ThemeService {
      * @param themeId theme id
      * @return List<ThemeFile>
      */
+    @NonNull
     List<ThemeFile> listThemeFolderBy(@NonNull String themeId);
 
     /**
@@ -143,7 +138,8 @@ public interface ThemeService {
      * @return a set of templates
      */
     @Deprecated
-    Set<String> listCustomTemplates(@NonNull String themeId);
+    @NonNull
+    List<String> listCustomTemplates(@NonNull String themeId);
 
     /**
      * Lists a set of custom template, such as sheet_xxx.ftl/post_xxx.ftl, and xxx will be template name
@@ -152,7 +148,8 @@ public interface ThemeService {
      * @param prefix  post_ or sheet_
      * @return a set of templates
      */
-    Set<String> listCustomTemplates(@NonNull String themeId, @NonNull String prefix);
+    @NonNull
+    List<String> listCustomTemplates(@NonNull String themeId, @NonNull String prefix);
 
     /**
      * Judging whether template exists under the specified theme
@@ -261,6 +258,14 @@ public interface ThemeService {
     @NonNull
     ThemeProperty getActivatedTheme();
 
+    /**
+     * Fetch activated theme property.
+     *
+     * @return activated theme property
+     */
+    @NonNull
+    Optional<ThemeProperty> fetchActivatedTheme();
+
     /**
      * Actives a theme.
      *

src/main/java/run/halo/app/service/impl/ThemeServiceImpl.java

@@ -19,7 +19,6 @@ import org.springframework.lang.NonNull;
 import org.springframework.lang.Nullable;
 import org.springframework.stereotype.Service;
 import org.springframework.util.Assert;
-import org.springframework.util.CollectionUtils;
 import org.springframework.web.client.RestTemplate;
 import org.springframework.web.multipart.MultipartFile;
 import run.halo.app.cache.AbstractStringCacheStore;
@@ -28,7 +27,6 @@ import run.halo.app.event.theme.ThemeActivatedEvent;
 import run.halo.app.event.theme.ThemeUpdatedEvent;
 import run.halo.app.exception.*;
 import run.halo.app.handler.theme.config.ThemeConfigResolver;
-import run.halo.app.handler.theme.config.ThemePropertyResolver;
 import run.halo.app.handler.theme.config.support.Group;
 import run.halo.app.handler.theme.config.support.ThemeProperty;
 import run.halo.app.model.properties.PrimaryProperties;
@@ -36,6 +34,8 @@ import run.halo.app.model.support.HaloConst;
 import run.halo.app.model.support.ThemeFile;
 import run.halo.app.service.OptionService;
 import run.halo.app.service.ThemeService;
+import run.halo.app.theme.ThemeFileScanner;
+import run.halo.app.theme.ThemePropertyScanner;
 import run.halo.app.utils.*;
 
 import java.io.IOException;
@@ -45,12 +45,12 @@ import java.nio.file.Files;
 import java.nio.file.Path;
 import java.nio.file.Paths;
 import java.util.*;
-import java.util.concurrent.Executors;
+import java.util.concurrent.atomic.AtomicReference;
-import java.util.concurrent.TimeUnit;
 import java.util.stream.Collectors;
 import java.util.stream.Stream;
 import java.util.zip.ZipInputStream;
 
+import static run.halo.app.model.support.HaloConst.DEFAULT_ERROR_PATH;
 import static run.halo.app.model.support.HaloConst.DEFAULT_THEME_ID;
 
 /**
@@ -63,23 +63,25 @@ import static run.halo.app.model.support.HaloConst.DEFAULT_THEME_ID;
 @Service
 public class ThemeServiceImpl implements ThemeService {
 
-    /**
-     * in seconds.
-     */
-    protected static final long ACTIVATED_THEME_SYNC_INTERVAL = 5;
     /**
      * Theme work directory.
      */
     private final Path themeWorkDir;
+
     private final OptionService optionService;
+
     private final AbstractStringCacheStore cacheStore;
+
     private final ThemeConfigResolver themeConfigResolver;
-    private final ThemePropertyResolver themePropertyResolver;
+
     private final RestTemplate restTemplate;
+
     private final ApplicationEventPublisher eventPublisher;
+
     /**
      * Activated theme id.
      */
+    @Nullable
     private volatile String activatedThemeId;
 
     /**
@@ -87,123 +89,77 @@ public class ThemeServiceImpl implements ThemeService {
      */
     private volatile ThemeProperty activatedTheme;
 
+    private final AtomicReference<String> activeThemeId = new AtomicReference<>();
+
     public ThemeServiceImpl(HaloProperties haloProperties,
                             OptionService optionService,
                             AbstractStringCacheStore cacheStore,
                             ThemeConfigResolver themeConfigResolver,
-                            ThemePropertyResolver themePropertyResolver,
                             RestTemplate restTemplate,
                             ApplicationEventPublisher eventPublisher) {
         this.optionService = optionService;
         this.cacheStore = cacheStore;
         this.themeConfigResolver = themeConfigResolver;
-        this.themePropertyResolver = themePropertyResolver;
         this.restTemplate = restTemplate;
 
         themeWorkDir = Paths.get(haloProperties.getWorkDir(), THEME_FOLDER);
         this.eventPublisher = eventPublisher;
-        // check activated theme option changes every 5 seconds.
-        Executors.newSingleThreadScheduledExecutor().scheduleWithFixedDelay(() -> {
-            try {
-                String newActivatedThemeId = optionService.getByPropertyOrDefault(PrimaryProperties.THEME, String.class, DEFAULT_THEME_ID);
-                if (!activatedThemeId.equals(newActivatedThemeId)) {
-                    activateTheme(newActivatedThemeId);
-                }
-            } catch (Exception e) {
-                log.warn("theme option sync exception: {}", e);
-            }
-        }, ACTIVATED_THEME_SYNC_INTERVAL, ACTIVATED_THEME_SYNC_INTERVAL, TimeUnit.SECONDS);
     }
 
     @Override
-    public ThemeProperty getThemeOfNonNullBy(String themeId) {
+    @NonNull
-        return getThemeBy(themeId).orElseThrow(() -> new NotFoundException("没有找到 id 为 " + themeId + " 的主题").setErrorData(themeId));
+    public ThemeProperty getThemeOfNonNullBy(@NonNull String themeId) {
+        return fetchThemePropertyBy(themeId).orElseThrow(() -> new NotFoundException(themeId + " 主题不存在或已删除！").setErrorData(themeId));
     }
 
     @Override
-    public Optional<ThemeProperty> getThemeBy(String themeId) {
+    @NonNull
+    public Optional<ThemeProperty> fetchThemePropertyBy(String themeId) {
         if (StringUtils.isBlank(themeId)) {
             return Optional.empty();
         }
 
         // Get all themes
-        Set<ThemeProperty> themes = getThemes();
+        List<ThemeProperty> themes = getThemes();
 
         // filter and find first
-        return themes.stream().filter(themeProperty -> StringUtils.equals(themeProperty.getId(), themeId)).findFirst();
+        return themes.stream()
+            .filter(themeProperty -> StringUtils.equals(themeProperty.getId(), themeId))
+            .findFirst();
     }
 
     @Override
-    public Set<ThemeProperty> getThemes() {
+    @NonNull
-
+    public List<ThemeProperty> getThemes() {
-        Optional<ThemeProperty[]> themePropertiesOptional = cacheStore.getAny(THEMES_CACHE_KEY, ThemeProperty[].class);
+        ThemeProperty[] themeProperties = cacheStore.getAny(THEMES_CACHE_KEY, ThemeProperty[].class).orElseGet(() -> {
-
+            List<ThemeProperty> properties = ThemePropertyScanner.INSTANCE.scan(getBasePath(), getActivatedThemeId());
-        if (themePropertiesOptional.isPresent()) {
-            // Convert to theme properties
-            ThemeProperty[] themeProperties = themePropertiesOptional.get();
-            return new HashSet<>(Arrays.asList(themeProperties));
-        }
-
-        try (Stream<Path> pathStream = Files.list(getBasePath())) {
-
-            // List and filter sub folders
-            List<Path> themePaths = pathStream.filter(path -> Files.isDirectory(path))
-                .collect(Collectors.toList());
-
-            if (CollectionUtils.isEmpty(themePaths)) {
-                return Collections.emptySet();
-            }
-
-            // Get theme properties
-            Set<ThemeProperty> themes = themePaths.stream().map(this::getProperty).collect(Collectors.toSet());
-
             // Cache the themes
-            cacheStore.putAny(THEMES_CACHE_KEY, themes);
+            cacheStore.putAny(THEMES_CACHE_KEY, properties);
-
+            return properties.toArray(new ThemeProperty[0]);
-            return themes;
+        });
-        } catch (IOException e) {
+        return Arrays.asList(themeProperties);
-            throw new ServiceException("Failed to get themes", e);
-        }
     }
 
     @Override
-    public List<ThemeFile> listThemeFolder(String absolutePath) {
+    @NonNull
-        return listThemeFileTree(Paths.get(absolutePath));
+    public List<ThemeFile> listThemeFolderBy(@NonNull String themeId) {
+        return fetchThemePropertyBy(themeId)
+            .map(themeProperty -> ThemeFileScanner.INSTANCE.scan(themeProperty.getThemePath()))
+            .orElse(Collections.emptyList());
     }
 
     @Override
-    public List<ThemeFile> listThemeFolderBy(String themeId) {
+    @NonNull
-        // Get the theme property
+    public List<String> listCustomTemplates(@NonNull String themeId) {
-        ThemeProperty themeProperty = getThemeOfNonNullBy(themeId);
+        return listCustomTemplates(themeId, CUSTOM_SHEET_PREFIX);
-
-        // List theme file as tree view
-        return listThemeFolder(themeProperty.getThemePath());
     }
 
     @Override
-    public Set<String> listCustomTemplates(String themeId) {
+    @NonNull
+    public List<String> listCustomTemplates(@NonNull String themeId, @NonNull String prefix) {
+        return fetchThemePropertyBy(themeId).map(themeProperty -> {
             // Get the theme path
-        Path themePath = Paths.get(getThemeOfNonNullBy(themeId).getThemePath());
+            Path themePath = Paths.get(themeProperty.getThemePath());
-
-        try (Stream<Path> pathStream = Files.list(themePath)) {
-            return pathStream.filter(path -> StringUtils.startsWithIgnoreCase(path.getFileName().toString(), CUSTOM_SHEET_PREFIX))
-                .map(path -> {
-                    // Remove prefix
-                    String customTemplate = StringUtils.removeStartIgnoreCase(path.getFileName().toString(), CUSTOM_SHEET_PREFIX);
-                    // Remove suffix
-                    return StringUtils.removeEndIgnoreCase(customTemplate, HaloConst.SUFFIX_FTL);
-                })
-                .collect(Collectors.toSet());
-        } catch (IOException e) {
-            throw new ServiceException("Failed to list files of path " + themePath.toString(), e);
-        }
-    }
-
-    @Override
-    public Set<String> listCustomTemplates(String themeId, String prefix) {
-        // Get the theme path
-        Path themePath = Paths.get(getThemeOfNonNullBy(themeId).getThemePath());
-
             try (Stream<Path> pathStream = Files.list(themePath)) {
                 return pathStream.filter(path -> StringUtils.startsWithIgnoreCase(path.getFileName().toString(), prefix))
                     .map(path -> {
@@ -212,10 +168,12 @@ public class ThemeServiceImpl implements ThemeService {
                         // Remove suffix
                         return StringUtils.removeEndIgnoreCase(customTemplate, HaloConst.SUFFIX_FTL);
                     })
-                .collect(Collectors.toSet());
+                    .distinct()
-        } catch (IOException e) {
+                    .collect(Collectors.toList());
-            throw new ServiceException("Failed to list files of path " + themePath.toString(), e);
+            } catch (Exception e) {
+                throw new ServiceException("Failed to list files of path " + themePath, e);
             }
+        }).orElse(Collections.emptyList());
     }
 
     @Override
@@ -224,19 +182,19 @@ public class ThemeServiceImpl implements ThemeService {
             return false;
         }
 
+        return fetchActivatedTheme().map(themeProperty -> {
             // Resolve template path
-        Path templatePath = Paths.get(getActivatedTheme().getThemePath(), template);
+            Path templatePath = Paths.get(themeProperty.getThemePath(), template);
-
             // Check the directory
             checkDirectory(templatePath.toString());
-
             // Check existence
             return Files.exists(templatePath);
+        }).orElse(false);
     }
 
     @Override
     public boolean themeExists(String themeId) {
-        return getThemeBy(themeId).isPresent();
+        return fetchThemePropertyBy(themeId).isPresent();
     }
 
     @Override
@@ -245,7 +203,7 @@ public class ThemeServiceImpl implements ThemeService {
     }
 
     @Override
-    public String getTemplateContent(String absolutePath) {
+    public String getTemplateContent(@NonNull String absolutePath) {
         // Check the path
         checkDirectory(absolutePath);
 
@@ -259,7 +217,8 @@ public class ThemeServiceImpl implements ThemeService {
     }
 
     @Override
-    public String getTemplateContent(String themeId, String absolutePath) {
+    @NonNull
+    public String getTemplateContent(@NonNull String themeId, @NonNull String absolutePath) {
         checkDirectory(themeId, absolutePath);
 
         // Read file
@@ -272,7 +231,7 @@ public class ThemeServiceImpl implements ThemeService {
     }
 
     @Override
-    public void saveTemplateContent(String absolutePath, String content) {
+    public void saveTemplateContent(@NonNull String absolutePath, String content) {
         // Check the path
         checkDirectory(absolutePath);
 
@@ -286,7 +245,7 @@ public class ThemeServiceImpl implements ThemeService {
     }
 
     @Override
-    public void saveTemplateContent(String themeId, String absolutePath, String content) {
+    public void saveTemplateContent(@NonNull String themeId, @NonNull String absolutePath, String content) {
         // Check the path
         checkDirectory(themeId, absolutePath);
 
@@ -300,7 +259,7 @@ public class ThemeServiceImpl implements ThemeService {
     }
 
     @Override
-    public void deleteTheme(String themeId) {
+    public void deleteTheme(@NonNull String themeId) {
         // Get the theme property
         ThemeProperty themeProperty = getThemeOfNonNullBy(themeId);
 
@@ -320,7 +279,8 @@ public class ThemeServiceImpl implements ThemeService {
     }
 
     @Override
-    public List<Group> fetchConfig(String themeId) {
+    @NonNull
+    public List<Group> fetchConfig(@NonNull String themeId) {
         Assert.hasText(themeId, "Theme id must not be blank");
 
         // Get theme property
@@ -358,10 +318,9 @@ public class ThemeServiceImpl implements ThemeService {
 
     @Override
     public String render(String pageName) {
-        // Get activated theme
+        return fetchActivatedTheme()
-        ThemeProperty activatedTheme = getActivatedTheme();
+            .map(themeProperty -> String.format(RENDER_TEMPLATE, themeProperty.getFolderName(), pageName))
-        // Build render url
+            .orElse(DEFAULT_ERROR_PATH);
-        return String.format(RENDER_TEMPLATE, activatedTheme.getFolderName(), pageName);
     }
 
     @Override
@@ -373,6 +332,7 @@ public class ThemeServiceImpl implements ThemeService {
     }
 
     @Override
+    @NonNull
     public String getActivatedThemeId() {
         if (activatedThemeId == null) {
             synchronized (this) {
@@ -381,11 +341,11 @@ public class ThemeServiceImpl implements ThemeService {
                 }
             }
         }
-
         return activatedThemeId;
     }
 
     @Override
+    @NonNull
     public ThemeProperty getActivatedTheme() {
         if (activatedTheme == null) {
             synchronized (this) {
@@ -395,10 +355,15 @@ public class ThemeServiceImpl implements ThemeService {
                 }
             }
         }
-
         return activatedTheme;
     }
 
+    @Override
+    @NonNull
+    public Optional<ThemeProperty> fetchActivatedTheme() {
+        return fetchThemePropertyBy(getActivatedThemeId());
+    }
+
     /**
      * Sets activated theme.
      *
@@ -410,7 +375,8 @@ public class ThemeServiceImpl implements ThemeService {
     }
 
     @Override
-    public ThemeProperty activateTheme(String themeId) {
+    @NonNull
+    public ThemeProperty activateTheme(@NonNull String themeId) {
         // Check existence of the theme
         ThemeProperty themeProperty = getThemeOfNonNullBy(themeId);
 
@@ -430,7 +396,8 @@ public class ThemeServiceImpl implements ThemeService {
     }
 
     @Override
-    public ThemeProperty upload(MultipartFile file) {
+    @NonNull
+    public ThemeProperty upload(@NonNull MultipartFile file) {
         Assert.notNull(file, "Multipart file must not be null");
 
         if (!StringUtils.endsWithIgnoreCase(file.getOriginalFilename(), ".zip")) {
@@ -443,7 +410,7 @@ public class ThemeServiceImpl implements ThemeService {
         try {
             // Create temp directory
             tempPath = FileUtils.createTempDirectory();
-            String basename = FilenameUtils.getBasename(file.getOriginalFilename());
+            String basename = FilenameUtils.getBasename(Objects.requireNonNull(file.getOriginalFilename()));
             Path themeTempPath = tempPath.resolve(basename);
 
             // Check directory traversal
@@ -455,10 +422,12 @@ public class ThemeServiceImpl implements ThemeService {
             // Unzip to temp path
             FileUtils.unzip(zis, themeTempPath);
 
+            Path themePath = FileUtils.tryToSkipZipParentFolder(themeTempPath);
+
             // Go to the base folder and add the theme into system
-            return add(FileUtils.tryToSkipZipParentFolder(themeTempPath));
+            return add(themePath);
         } catch (IOException e) {
-            throw new ServiceException("上传主题失败: " + file.getOriginalFilename(), e);
+            throw new ServiceException("主题上传失败: " + file.getOriginalFilename(), e);
         } finally {
             // Close zip input stream
             FileUtils.closeQuietly(zis);
@@ -468,7 +437,8 @@ public class ThemeServiceImpl implements ThemeService {
     }
 
     @Override
-    public ThemeProperty add(Path themeTmpPath) throws IOException {
+    @NonNull
+    public ThemeProperty add(@NonNull Path themeTmpPath) throws IOException {
         Assert.notNull(themeTmpPath, "Theme temporary path must not be null");
         Assert.isTrue(Files.isDirectory(themeTmpPath), "Theme temporary path must be a directory");
 
@@ -509,7 +479,7 @@ public class ThemeServiceImpl implements ThemeService {
     }
 
     @Override
-    public ThemeProperty fetch(String uri) {
+    public ThemeProperty fetch(@NonNull String uri) {
         Assert.hasText(uri, "Theme remote uri must not be blank");
 
         Path tmpPath = null;
@@ -621,7 +591,8 @@ public class ThemeServiceImpl implements ThemeService {
         }
     }
 
-    private void pullFromGit(@NonNull ThemeProperty themeProperty) throws IOException, GitAPIException, URISyntaxException {
+    private void pullFromGit(@NonNull ThemeProperty themeProperty) throws
+        IOException, GitAPIException, URISyntaxException {
         Assert.notNull(themeProperty, "Theme property must not be null");
 
         // Get branch
@@ -637,7 +608,9 @@ public class ThemeServiceImpl implements ThemeService {
 
             RevWalk revWalk = new RevWalk(repository);
 
-            Ref ref = repository.getAllRefs().get(Constants.HEAD);
+            Ref ref = repository.findRef(Constants.HEAD);
+
+            Assert.notNull(ref, Constants.HEAD + " ref was not found!");
 
             RevCommit lastCommit = revWalk.parseCommit(ref.getObjectId());
 
@@ -728,74 +701,6 @@ public class ThemeServiceImpl implements ThemeService {
         FileUtils.unzip(downloadResponse.getBody(), targetPath);
     }
 
-    /**
-     * Lists theme files as tree view.
-     *
-     * @param topPath must not be null
-     * @return theme file tree view or null only if the top path is not a directory
-     */
-    @Nullable
-    private List<ThemeFile> listThemeFileTree(@NonNull Path topPath) {
-        Assert.notNull(topPath, "Top path must not be null");
-
-        // Check file type
-        if (!Files.isDirectory(topPath)) {
-            return null;
-        }
-
-        try (Stream<Path> pathStream = Files.list(topPath)) {
-            List<ThemeFile> themeFiles = new LinkedList<>();
-
-            pathStream.forEach(path -> {
-                // Build theme file
-                ThemeFile themeFile = new ThemeFile();
-                themeFile.setName(path.getFileName().toString());
-                themeFile.setPath(path.toString());
-                themeFile.setIsFile(Files.isRegularFile(path));
-                themeFile.setEditable(isEditable(path));
-
-                if (Files.isDirectory(path)) {
-                    themeFile.setNode(listThemeFileTree(path));
-                }
-
-                // Add to theme files
-                themeFiles.add(themeFile);
-            });
-
-            // Sort with isFile param
-            themeFiles.sort(new ThemeFile());
-
-            return themeFiles;
-        } catch (IOException e) {
-            throw new ServiceException("Failed to list sub files", e);
-        }
-    }
-
-    /**
-     * Check if the given path is editable.
-     *
-     * @param path must not be null
-     * @return true if the given path is editable; false otherwise
-     */
-    private boolean isEditable(@NonNull Path path) {
-        Assert.notNull(path, "Path must not be null");
-
-        boolean isEditable = Files.isReadable(path) && Files.isWritable(path);
-
-        if (!isEditable) {
-            return false;
-        }
-
-        // Check suffix
-        for (String suffix : CAN_EDIT_SUFFIX) {
-            if (path.toString().endsWith(suffix)) {
-                return true;
-            }
-        }
-
-        return false;
-    }
-
     /**
      * Check if directory is valid or not.
      *
@@ -818,82 +723,6 @@ public class ThemeServiceImpl implements ThemeService {
         FileUtils.checkDirectoryTraversal(themeProperty.getThemePath(), absoluteName);
     }
 
-    /**
-     * Gets property path of nullable.
-     *
-     * @param themePath theme path.
-     * @return an optional property path
-     */
-    @NonNull
-    private Optional<Path> getThemePropertyPathOfNullable(@NonNull Path themePath) {
-        Assert.notNull(themePath, "Theme path must not be null");
-
-        for (String propertyPathName : THEME_PROPERTY_FILE_NAMES) {
-            Path propertyPath = themePath.resolve(propertyPathName);
-
-            log.debug("Attempting to find property file: [{}]", propertyPath);
-            if (Files.exists(propertyPath) && Files.isReadable(propertyPath)) {
-                log.debug("Found property file: [{}]", propertyPath);
-                return Optional.of(propertyPath);
-            }
-        }
-
-        log.warn("Property file was not found in [{}]", themePath);
-
-        return Optional.empty();
-    }
-
-    /**
-     * Gets property path of non null.
-     *
-     * @param themePath theme path.
-     * @return property path won't be null
-     */
-    @NonNull
-    private Path getThemePropertyPath(@NonNull Path themePath) {
-        return getThemePropertyPathOfNullable(themePath).orElseThrow(() -> new ThemePropertyMissingException(themePath + " 没有说明文件").setErrorData(themePath));
-    }
-
-    private Optional<ThemeProperty> getPropertyOfNullable(Path themePath) {
-        Assert.notNull(themePath, "Theme path must not be null");
-
-        Path propertyPath = getThemePropertyPath(themePath);
-
-        try {
-            // Get property content
-            String propertyContent = new String(Files.readAllBytes(propertyPath), StandardCharsets.UTF_8);
-
-            // Resolve the base properties
-            ThemeProperty themeProperty = themePropertyResolver.resolve(propertyContent);
-
-            // Resolve additional properties
-            themeProperty.setThemePath(themePath.toString());
-            themeProperty.setFolderName(themePath.getFileName().toString());
-            themeProperty.setHasOptions(hasOptions(themePath));
-            themeProperty.setActivated(false);
-
-            // Set screenshots
-            getScreenshotsFileName(themePath).ifPresent(screenshotsName ->
-                themeProperty.setScreenshots(StringUtils.join(optionService.getBlogBaseUrl(),
-                    "/themes/",
-                    FilenameUtils.getBasename(themeProperty.getThemePath()),
-                    "/",
-                    screenshotsName)));
-
-            if (StringUtils.equals(themeProperty.getId(), getActivatedThemeId())) {
-                // Set activation
-                themeProperty.setActivated(true);
-            }
-
-            return Optional.of(themeProperty);
-
-        } catch (IOException e) {
-            log.error("Failed to load theme property file", e);
-        }
-
-        return Optional.empty();
-    }
-
     /**
      * Gets theme property.
      *
@@ -902,48 +731,8 @@ public class ThemeServiceImpl implements ThemeService {
      */
     @NonNull
     private ThemeProperty getProperty(@NonNull Path themePath) {
-        return getPropertyOfNullable(themePath).orElseThrow(() -> new ThemePropertyMissingException(themePath + " 没有说明文件").setErrorData(themePath));
+        return ThemePropertyScanner.INSTANCE.fetchThemeProperty(themePath)
+            .orElseThrow(() -> new ThemePropertyMissingException(themePath + " 没有说明文件").setErrorData(themePath));
     }
 
-    /**
-     * Gets screenshots file name.
-     *
-     * @param themePath theme path must not be null
-     * @return screenshots file name or null if the given theme path has not screenshots
-     * @throws IOException throws when listing files
-     */
-    @NonNull
-    private Optional<String> getScreenshotsFileName(@NonNull Path themePath) throws IOException {
-        Assert.notNull(themePath, "Theme path must not be null");
-
-        try (Stream<Path> pathStream = Files.list(themePath)) {
-            return pathStream.filter(path -> Files.isRegularFile(path)
-                && Files.isReadable(path)
-                && FilenameUtils.getBasename(path.toString()).equalsIgnoreCase(THEME_SCREENSHOTS_NAME))
-                .findFirst()
-                .map(path -> path.getFileName().toString());
-        }
-    }
-
-    /**
-     * Check existence of the options.
-     *
-     * @param themePath theme path must not be null
-     * @return true if it has options; false otherwise
-     */
-    private boolean hasOptions(@NonNull Path themePath) {
-        Assert.notNull(themePath, "Path must not be null");
-
-        for (String optionsName : SETTINGS_NAMES) {
-            // Resolve the options path
-            Path optionsPath = themePath.resolve(optionsName);
-
-            log.debug("Check options file for path: [{}]", optionsPath);
-
-            if (Files.exists(optionsPath)) {
-                return true;
-            }
-        }
-        return false;
-    }
 }

src/main/java/run/halo/app/theme/ThemeFileScanner.java

@@ -0,0 +1,108 @@
+package run.halo.app.theme;
+
+import org.springframework.lang.NonNull;
+import org.springframework.util.Assert;
+import run.halo.app.exception.ServiceException;
+import run.halo.app.model.support.ThemeFile;
+
+import java.io.IOException;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.nio.file.Paths;
+import java.util.Collections;
+import java.util.LinkedList;
+import java.util.List;
+import java.util.stream.Stream;
+
+import static run.halo.app.service.ThemeService.CAN_EDIT_SUFFIX;
+
+/**
+ * Theme file scanner.
+ *
+ * @author johnniang
+ */
+public enum ThemeFileScanner {
+
+    INSTANCE;
+
+    /**
+     * Lists theme folder by absolute path.
+     *
+     * @param absolutePath absolutePath
+     * @return List<ThemeFile> a list of theme files
+     */
+    @NonNull
+    public List<ThemeFile> scan(@NonNull String absolutePath) {
+        Assert.hasText(absolutePath, "Absolute path must not be blank");
+
+        return scan(Paths.get(absolutePath));
+    }
+
+    /**
+     * Lists theme files as tree view.
+     *
+     * @param rootPath theme root path must not be null
+     * @return theme file tree view
+     */
+    @NonNull
+    private List<ThemeFile> scan(@NonNull Path rootPath) {
+        Assert.notNull(rootPath, "Root path must not be null");
+
+        // Check file type
+        if (!Files.isDirectory(rootPath)) {
+            return Collections.emptyList();
+        }
+
+        try (Stream<Path> pathStream = Files.list(rootPath)) {
+            List<ThemeFile> themeFiles = new LinkedList<>();
+
+            pathStream.forEach(path -> {
+                // Build theme file
+                ThemeFile themeFile = new ThemeFile();
+                themeFile.setName(path.getFileName().toString());
+                themeFile.setPath(path.toString());
+                themeFile.setIsFile(Files.isRegularFile(path));
+                themeFile.setEditable(isEditable(path));
+
+                if (Files.isDirectory(path)) {
+                    themeFile.setNode(scan(path));
+                }
+
+                // Add to theme files
+                themeFiles.add(themeFile);
+            });
+
+            // Sort with isFile param
+            themeFiles.sort(new ThemeFile());
+
+            return themeFiles;
+        } catch (IOException e) {
+            throw new ServiceException("Failed to list sub files", e);
+        }
+    }
+
+    /**
+     * Check if the given path is editable.
+     *
+     * @param path must not be null
+     * @return true if the given path is editable; false otherwise
+     */
+    private boolean isEditable(@NonNull Path path) {
+        Assert.notNull(path, "Path must not be null");
+
+        boolean isEditable = Files.isReadable(path) && Files.isWritable(path);
+
+        if (!isEditable) {
+            return false;
+        }
+
+        // Check suffix
+        for (String suffix : CAN_EDIT_SUFFIX) {
+            if (path.toString().endsWith(suffix)) {
+                return true;
+            }
+        }
+
+        return false;
+    }
+}

src/main/java/run/halo/app/theme/ThemePropertyScanner.java

@@ -0,0 +1,207 @@
+package run.halo.app.theme;
+
+import lombok.extern.slf4j.Slf4j;
+import org.apache.commons.lang3.StringUtils;
+import org.springframework.lang.NonNull;
+import org.springframework.lang.Nullable;
+import org.springframework.util.Assert;
+import org.springframework.util.CollectionUtils;
+import run.halo.app.handler.theme.config.ThemePropertyResolver;
+import run.halo.app.handler.theme.config.impl.YamlThemePropertyResolver;
+import run.halo.app.handler.theme.config.support.ThemeProperty;
+import run.halo.app.utils.FilenameUtils;
+
+import java.io.IOException;
+import java.nio.charset.StandardCharsets;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.util.Arrays;
+import java.util.Collections;
+import java.util.List;
+import java.util.Optional;
+import java.util.stream.Collectors;
+import java.util.stream.Stream;
+
+import static run.halo.app.service.ThemeService.SETTINGS_NAMES;
+
+/**
+ * Theme property scanner.
+ *
+ * @author johnniang
+ */
+@Slf4j
+public enum ThemePropertyScanner {
+
+    INSTANCE;
+
+    private final ThemePropertyResolver propertyResolver = new YamlThemePropertyResolver();
+
+    /**
+     * Theme property file name.
+     */
+    private static final String[] THEME_PROPERTY_FILE_NAMES = {"theme.yaml", "theme.yml"};
+
+    /**
+     * Theme screenshots name.
+     */
+    private static final String THEME_SCREENSHOTS_NAME = "screenshot";
+
+    /**
+     * Scan theme properties.
+     *
+     * @param themePath them path must not be null
+     * @return a list of them property
+     */
+    @NonNull
+    public List<ThemeProperty> scan(@NonNull Path themePath, @Nullable String activeThemeId) {
+        // create if absent
+        try {
+            if (Files.notExists(themePath)) {
+                Files.createDirectories(themePath);
+            }
+        } catch (IOException e) {
+            log.error("Failed to create directory: " + themePath, e);
+            return Collections.emptyList();
+        }
+        try (Stream<Path> pathStream = Files.list(themePath)) {
+            // List and filter sub folders
+            List<Path> themePaths = pathStream.filter(path -> Files.isDirectory(path))
+                .collect(Collectors.toList());
+
+            if (CollectionUtils.isEmpty(themePaths)) {
+                return Collections.emptyList();
+            }
+
+            // Get theme properties
+            ThemeProperty[] properties = themePaths.stream()
+                .map(this::fetchThemeProperty)
+                .filter(Optional::isPresent)
+                .map(Optional::get)
+                .peek(themeProperty -> {
+                    if (StringUtils.equals(activeThemeId, themeProperty.getId())) {
+                        themeProperty.setActivated(true);
+                    }
+                })
+                .toArray(ThemeProperty[]::new);
+            // Cache the themes
+            return Arrays.asList(properties);
+        } catch (IOException e) {
+            log.error("Failed to get themes", e);
+            return Collections.emptyList();
+        }
+    }
+
+    /**
+     * Fetch theme property
+     *
+     * @param themePath theme path must not be null
+     * @return an optional theme property
+     */
+    @NonNull
+    public Optional<ThemeProperty> fetchThemeProperty(@NonNull Path themePath) {
+        Assert.notNull(themePath, "Theme path must not be null");
+
+        Optional<Path> optionalPath = fetchPropertyPath(themePath);
+
+        if (!optionalPath.isPresent()) {
+            return Optional.empty();
+        }
+
+        Path propertyPath = optionalPath.get();
+
+        try {
+            // Get property content
+            String propertyContent = new String(Files.readAllBytes(propertyPath), StandardCharsets.UTF_8);
+
+            // Resolve the base properties
+            ThemeProperty themeProperty = propertyResolver.resolve(propertyContent);
+
+            // Resolve additional properties
+            themeProperty.setThemePath(themePath.toString());
+            themeProperty.setFolderName(themePath.getFileName().toString());
+            themeProperty.setHasOptions(hasOptions(themePath));
+            themeProperty.setActivated(false);
+
+            // Set screenshots
+            getScreenshotsFileName(themePath).ifPresent(screenshotsName ->
+                // TODO base url
+                themeProperty.setScreenshots(StringUtils.join(
+                    "/themes/",
+                    FilenameUtils.getBasename(themeProperty.getThemePath()),
+                    "/",
+                    screenshotsName)));
+
+            return Optional.of(themeProperty);
+        } catch (Exception e) {
+            log.warn("Failed to load theme property file", e);
+        }
+        return Optional.empty();
+    }
+
+    /**
+     * Gets screenshots file name.
+     *
+     * @param themePath theme path must not be null
+     * @return screenshots file name or null if the given theme path has not screenshots
+     * @throws IOException throws when listing files
+     */
+    @NonNull
+    private Optional<String> getScreenshotsFileName(@NonNull Path themePath) throws IOException {
+        Assert.notNull(themePath, "Theme path must not be null");
+
+        try (Stream<Path> pathStream = Files.list(themePath)) {
+            return pathStream.filter(path -> Files.isRegularFile(path)
+                && Files.isReadable(path)
+                && FilenameUtils.getBasename(path.toString()).equalsIgnoreCase(THEME_SCREENSHOTS_NAME))
+                .findFirst()
+                .map(path -> path.getFileName().toString());
+        }
+    }
+
+    /**
+     * Gets property path of nullable.
+     *
+     * @param themePath theme path.
+     * @return an optional property path
+     */
+    @NonNull
+    private Optional<Path> fetchPropertyPath(@NonNull Path themePath) {
+        Assert.notNull(themePath, "Theme path must not be null");
+
+        for (String propertyPathName : THEME_PROPERTY_FILE_NAMES) {
+            Path propertyPath = themePath.resolve(propertyPathName);
+
+            log.debug("Attempting to find property file: [{}]", propertyPath);
+            if (Files.exists(propertyPath) && Files.isReadable(propertyPath)) {
+                log.debug("Found property file: [{}]", propertyPath);
+                return Optional.of(propertyPath);
+            }
+        }
+
+        log.warn("Property file was not found in [{}]", themePath);
+
+        return Optional.empty();
+    }
+
+    /**
+     * Check existence of the options.
+     *
+     * @param themePath theme path must not be null
+     * @return true if it has options; false otherwise
+     */
+    private boolean hasOptions(@NonNull Path themePath) {
+        Assert.notNull(themePath, "Path must not be null");
+
+        for (String optionsName : SETTINGS_NAMES) {
+            // Resolve the options path
+            Path optionsPath = themePath.resolve(optionsName);
+
+            log.debug("Check options file for path: [{}]", optionsPath);
+
+            if (Files.exists(optionsPath)) {
+                return true;
+            }
+        }
+        return false;
+    }
+}

src/main/java/run/halo/app/theme/YamlResolver.java

@@ -0,0 +1,34 @@
+package run.halo.app.theme;
+
+import com.fasterxml.jackson.databind.DeserializationFeature;
+import com.fasterxml.jackson.databind.ObjectMapper;
+import com.fasterxml.jackson.dataformat.yaml.YAMLFactory;
+import org.springframework.lang.NonNull;
+
+/**
+ * Yaml resolver.
+ *
+ * @author johnniang
+ */
+public enum YamlResolver {
+
+    INSTANCE;
+
+    private final ObjectMapper yamlMapper;
+
+    YamlResolver() {
+        // create a default yaml mapper
+        yamlMapper = new ObjectMapper(new YAMLFactory());
+        yamlMapper.configure(DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES, false);
+    }
+
+    /**
+     * Get yaml mapper.
+     *
+     * @return non-null yaml mapper
+     */
+    @NonNull
+    public ObjectMapper getYamlMapper() {
+        return yamlMapper;
+    }
+}

src/main/resources/templates/common/error/error.ftl

@@ -5,7 +5,7 @@
     <meta charset="UTF-8">
     <meta name="viewport" content="width=device-width,initial-scale=1">
     <link rel="alternate" type="application/rss+xml" title="atom 1.0" href="${atom_url!}">
-    <title>${error.status!} | ${error.error!}</title>
+    <title>${(error.status)!500} | ${(error.error)!'未知错误'}</title>
 
     <style type="text/css">
         body {
@@ -121,9 +121,9 @@
 <body>
 
 <div class="container">
-    <h2>${error.status!}</h2>
+    <h2>${(error.status)!500}</h2>
-    <h1 class="title">${error.error!}.</h1>
+    <h1 class="title">${(error.error)!'未知错误'}.</h1>
-    <p>${error.message!}</p>
+    <p>${(error.message)!'未知错误！可能存在的原因：未正确设置主题或主题文件缺失。'}</p>
     <div class="back-home">
         <button onclick="window.location.href='${blog_url!}'">首页</button>
     </div>