Refactor freemarker configuration with event

src/main/java/run/halo/app/Application.java

@@ -1,5 +1,6 @@
 package run.halo.app;
 
+import org.springframework.scheduling.annotation.EnableAsync;
 import run.halo.app.repository.base.BaseRepositoryImpl;
 import org.springframework.boot.SpringApplication;
 import org.springframework.boot.autoconfigure.SpringBootApplication;
@@ -18,6 +19,7 @@ import org.springframework.scheduling.annotation.EnableScheduling;
 @SpringBootApplication
 @EnableJpaAuditing
 @EnableScheduling
+@EnableAsync
 @EnableJpaRepositories(basePackages = "run.halo.app.repository", repositoryBaseClass = BaseRepositoryImpl.class)
 public class Application {
 

src/main/java/run/halo/app/event/theme/FreemarkerConfigAwareListener.java

@@ -0,0 +1,66 @@
+package run.halo.app.event.theme;
+
+import freemarker.template.Configuration;
+import freemarker.template.TemplateModelException;
+import lombok.extern.slf4j.Slf4j;
+import org.springframework.boot.context.event.ApplicationStartedEvent;
+import org.springframework.context.event.EventListener;
+import org.springframework.scheduling.annotation.Async;
+import org.springframework.stereotype.Component;
+import run.halo.app.handler.theme.config.support.ThemeProperty;
+import run.halo.app.service.OptionService;
+import run.halo.app.service.ThemeService;
+
+import java.util.Map;
+
+/**
+ * Theme activated listener.
+ *
+ * @author johnniang
+ * @date 19-4-20
+ */
+@Component
+@Slf4j
+public class FreemarkerConfigAwareListener {
+
+    private final OptionService optionService;
+
+    private final Configuration configuration;
+
+    private final ThemeService themeService;
+
+    public FreemarkerConfigAwareListener(OptionService optionService,
+                                         Configuration configuration,
+                                         ThemeService themeService) {
+        this.optionService = optionService;
+        this.configuration = configuration;
+        this.themeService = themeService;
+    }
+
+    @Async
+    @EventListener
+    public void onApplicationStartedEvent(ApplicationStartedEvent applicationStartedEvent) {
+        try {
+            ThemeProperty activatedTheme = themeService.getActivatedTheme();
+            log.debug("Set shared variable theme: [{}]", activatedTheme);
+            configuration.setSharedVariable("theme", activatedTheme);
+        } catch (TemplateModelException e) {
+            log.warn("Failed to configure freemarker", e);
+        }
+    }
+
+    @Async
+    @EventListener
+    public void onThemeActivatedEvent(ThemeActivatedEvent themeActivatedEvent) {
+        try {
+            ThemeProperty activatedTheme = themeActivatedEvent.getThemeProperty();
+            log.debug("Set shared variable theme: [{}]", activatedTheme);
+            configuration.setSharedVariable("theme", activatedTheme);
+            Map<String, String> options = optionService.listOptions();
+            log.debug("Set shared variable options: [{}]", options);
+            configuration.setSharedVariable("options", options);
+        } catch (TemplateModelException e) {
+            log.warn("Failed to configure freemarker", e);
+        }
+    }
+}

src/main/java/run/halo/app/event/theme/ThemeActivatedEvent.java

@@ -0,0 +1,33 @@
+package run.halo.app.event.theme;
+
+import org.springframework.context.ApplicationEvent;
+import org.springframework.lang.NonNull;
+import org.springframework.util.Assert;
+import run.halo.app.handler.theme.config.support.ThemeProperty;
+
+/**
+ * Theme activated event.
+ *
+ * @author johnniang
+ * @date 19-4-20
+ */
+public class ThemeActivatedEvent extends ApplicationEvent {
+
+    private final ThemeProperty themeProperty;
+
+    /**
+     * Create a new ApplicationEvent.
+     *
+     * @param source        the object on which the event initially occurred (never {@code null})
+     * @param themeProperty theme property must not be null
+     */
+    public ThemeActivatedEvent(Object source, @NonNull ThemeProperty themeProperty) {
+        super(source);
+        Assert.notNull(themeProperty, "Activated theme property must not be null");
+        this.themeProperty = themeProperty;
+    }
+
+    public ThemeProperty getThemeProperty() {
+        return themeProperty;
+    }
+}

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

@@ -61,7 +61,7 @@ public class StartedListener implements ApplicationListener<ApplicationStartedEv
     public void onApplicationEvent(ApplicationStartedEvent event) {
         // save halo version to database
         this.cacheOwo();
-        this.cacheActiveTheme();
+//        this.cacheActiveTheme();
         this.printStartInfo();
         this.initThemes();
 
@@ -97,7 +97,7 @@ public class StartedListener implements ApplicationListener<ApplicationStartedEv
      */
     private void cacheActiveTheme() {
         try {
-            configuration.setSharedVariable("themeId", themeService.getActivatedThemeId());
+            configuration.setSharedVariable("theme", themeService.getActivatedTheme());
         } catch (TemplateModelException e) {
             log.error("", e);
         }

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

@@ -6,11 +6,11 @@ import cn.hutool.core.io.file.FileWriter;
 import cn.hutool.core.text.StrBuilder;
 import cn.hutool.core.util.StrUtil;
 import freemarker.template.Configuration;
-import freemarker.template.TemplateModelException;
 import lombok.extern.slf4j.Slf4j;
 import org.apache.commons.lang3.StringUtils;
 import org.eclipse.jgit.api.Git;
 import org.eclipse.jgit.api.errors.GitAPIException;
+import org.springframework.context.ApplicationEventPublisher;
 import org.springframework.http.ResponseEntity;
 import org.springframework.lang.NonNull;
 import org.springframework.lang.Nullable;
@@ -21,6 +21,7 @@ import org.springframework.web.client.RestTemplate;
 import org.springframework.web.multipart.MultipartFile;
 import run.halo.app.cache.StringCacheStore;
 import run.halo.app.config.properties.HaloProperties;
+import run.halo.app.event.theme.ThemeActivatedEvent;
 import run.halo.app.exception.*;
 import run.halo.app.handler.theme.config.ThemeConfigResolver;
 import run.halo.app.handler.theme.config.ThemePropertyResolver;
@@ -74,6 +75,8 @@ public class ThemeServiceImpl implements ThemeService {
 
     private final RestTemplate restTemplate;
 
+    private final ApplicationEventPublisher eventPublisher;
+
     /**
      * Activated theme id.
      */
@@ -90,7 +93,8 @@ public class ThemeServiceImpl implements ThemeService {
                             Configuration configuration,
                             ThemeConfigResolver themeConfigResolver,
                             ThemePropertyResolver themePropertyResolver,
-                            RestTemplate restTemplate) {
+                            RestTemplate restTemplate,
+                            ApplicationEventPublisher eventPublisher) {
         this.optionService = optionService;
         this.cacheStore = cacheStore;
         this.configuration = configuration;
@@ -99,6 +103,7 @@ public class ThemeServiceImpl implements ThemeService {
         this.restTemplate = restTemplate;
 
         workDir = Paths.get(haloProperties.getWorkDir(), THEME_FOLDER);
+        this.eventPublisher = eventPublisher;
     }
 
     @Override
@@ -112,9 +117,6 @@ public class ThemeServiceImpl implements ThemeService {
 
         Set<ThemeProperty> themes = getThemes();
 
-        log.debug("Themes type: [{}]", themes.getClass());
-        log.debug("Themes: [{}]", themes);
-
         return themes.stream().filter(themeProperty -> StringUtils.equals(themeProperty.getId(), themeId)).findFirst();
     }
 
@@ -327,13 +329,8 @@ public class ThemeServiceImpl implements ThemeService {
         // Clear the cache
         clearThemeCache();
 
-        try {
-            // TODO Refactor here in the future
-            configuration.setSharedVariable("themeId", themeId);
-            configuration.setSharedVariable("options", optionService.listOptions());
-        } catch (TemplateModelException e) {
-            throw new ServiceException("Failed to set shared variable", e).setErrorData(themeId);
-        }
+        // Publish a theme activated event
+        eventPublisher.publishEvent(new ThemeActivatedEvent(this, themeProperty));
 
         return themeProperty;
     }