(refs #1238) Add new extension point to supply assets by plugin

build.sbt

@@ -1,6 +1,6 @@
 val Organization = "gitbucket"
 val Name = "gitbucket"
-val GitBucketVersion = "4.2.1"
+val GitBucketVersion = "4.3.0-SNAPSHOT"
 val ScalatraVersion = "2.4.1"
 val JettyVersion = "9.3.9.v20160517"
 

src/main/scala/gitbucket/core/plugin/Plugin.scala

@@ -149,6 +149,16 @@ abstract class Plugin {
    */
   def dashboardTabs(registry: PluginRegistry, context: ServletContext, settings: SystemSettings): Seq[(Context) => Option[Link]] = Nil
 
+  /**
+   * Override to add assets mappings.
+   */
+  val assetsMappings: Seq[(String, String)] = Nil
+
+  /**
+   * Override to add assets mappings.
+   */
+  def assetsMappings(registry: PluginRegistry, context: ServletContext, settings: SystemSettings): Seq[(String, String)] = Nil
+
   /**
    * This method is invoked in initialization of plugin system.
    * Register plugin functionality to PluginRegistry.
@@ -193,6 +203,9 @@ abstract class Plugin {
     (dashboardTabs ++ dashboardTabs(registry, context, settings)).foreach { dashboardTab =>
       registry.addDashboardTab(dashboardTab)
     }
+    (assetsMappings ++ assetsMappings(registry, context, settings)).foreach { assetMapping =>
+      registry.addAssetsMapping((assetMapping._1, assetMapping._2, getClass.getClassLoader))
+    }
   }
 
   /**

src/main/scala/gitbucket/core/plugin/PluginRegistory.scala

@@ -41,6 +41,7 @@ class PluginRegistry {
   private val systemSettingMenus = new ListBuffer[(Context) => Option[Link]]
   private val accountSettingMenus = new ListBuffer[(Context) => Option[Link]]
   private val dashboardTabs = new ListBuffer[(Context) => Option[Link]]
+  private val assetsMappings = new ListBuffer[(String, String, ClassLoader)]
 
   def addPlugin(pluginInfo: PluginInfo): Unit = {
     plugins += pluginInfo
@@ -158,6 +159,12 @@ class PluginRegistry {
 
   def getDashboardTabs: Seq[(Context) => Option[Link]] = dashboardTabs.toSeq
 
+  def addAssetsMapping(assetsMapping: (String, String, ClassLoader)): Unit = {
+    assetsMappings += assetsMapping
+  }
+
+  def getAssetsMappings: Seq[(String, String, ClassLoader)] = assetsMappings.toSeq
+
 }
 
 /**

src/main/scala/gitbucket/core/servlet/PluginAssetsServlet.scala

@@ -0,0 +1,39 @@
+package gitbucket.core.servlet
+
+import javax.servlet.http.{HttpServlet, HttpServletRequest, HttpServletResponse}
+
+import gitbucket.core.plugin.PluginRegistry
+import gitbucket.core.util.FileUtil
+import org.apache.commons.io.IOUtils
+
+/**
+ * Supply assets which are provided by plugins.
+ */
+class PluginAssetsServlet extends HttpServlet {
+
+  override def doGet(req: HttpServletRequest, resp: HttpServletResponse): Unit = {
+    val assetsMappings = PluginRegistry().getAssetsMappings
+    val path = req.getRequestURI.substring(req.getContextPath.length)
+
+    assetsMappings
+      .find    { case (prefix, _, _) => path.startsWith("/plugin-assets" + prefix) }
+      .flatMap { case (prefix, resourcePath, classLoader) =>
+        val resourceName = path.substring(("/plugin-assets" + prefix).length)
+        Option(classLoader.getResourceAsStream(resourcePath + resourceName))
+      }
+      .map { in =>
+        try {
+          val bytes = IOUtils.toByteArray(in)
+          resp.setContentLength(bytes.length)
+          resp.setContentType(FileUtil.getContentType(path, bytes))
+          resp.getOutputStream.write(bytes)
+        } finally {
+          in.close()
+        }
+      }
+      .getOrElse {
+        resp.setStatus(404)
+      }
+  }
+
+}

src/main/webapp/WEB-INF/web.xml

@@ -45,7 +45,20 @@
     <servlet-name>GitRepositoryServlet</servlet-name>
     <url-pattern>/git/*</url-pattern>
   </servlet-mapping>
- 
+
+  <!-- ===================================================================== -->
+  <!-- Supply assets which are provided by plugins -->
+  <!-- ===================================================================== -->
+  <servlet>
+    <servlet-name>PluginAssetsServlet</servlet-name>
+    <servlet-class>gitbucket.core.servlet.PluginAssetsServlet</servlet-class>
+  </servlet>
+
+  <servlet-mapping>
+    <servlet-name>PluginAssetsServlet</servlet-name>
+    <url-pattern>/plugin-assets/*</url-pattern>
+  </servlet-mapping>
+
   <!-- ===================================================================== -->
   <!-- H2 console configuration -->
   <!-- ===================================================================== -->