implemented WebResourceServlet, which loads resources from the UberWebResourceLoader

scm-webapp/src/main/java/sonia/scm/WebResourceServlet.java

@@ -0,0 +1,77 @@
+package sonia.scm;
+
+import com.google.common.annotations.VisibleForTesting;
+import com.google.common.io.Resources;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+import sonia.scm.filter.WebElement;
+import sonia.scm.plugin.PluginLoader;
+import sonia.scm.plugin.UberWebResourceLoader;
+import sonia.scm.util.HttpUtil;
+
+import javax.inject.Inject;
+import javax.inject.Singleton;
+import javax.servlet.http.HttpServlet;
+import javax.servlet.http.HttpServletRequest;
+import javax.servlet.http.HttpServletResponse;
+import java.io.IOException;
+import java.io.OutputStream;
+import java.net.URL;
+
+/**
+ * WebResourceServlet serves resources from the {@link UberWebResourceLoader}.
+ *
+ * @since 2.0.0
+ */
+@Singleton
+@WebElement(value = WebResourceServlet.PATTERN, regex = true)
+public class WebResourceServlet extends HttpServlet {
+
+  /**
+   * exclude api requests and the old frontend servlets.
+   *
+   * TODO remove old frontend servlets
+   */
+  @VisibleForTesting
+  static final String PATTERN = "/(?!api/|index.html|error.html|plugins/resources).+";
+
+  private static final Logger LOG = LoggerFactory.getLogger(WebResourceServlet.class);
+
+  private final UberWebResourceLoader webResourceLoader;
+
+  @Inject
+  public WebResourceServlet(PluginLoader pluginLoader) {
+    this.webResourceLoader = pluginLoader.getUberWebResourceLoader();
+  }
+
+  @Override
+  protected void doGet(HttpServletRequest request, HttpServletResponse response) {
+    String uri = normalizeUri(request);
+
+    LOG.trace("try to load {}", uri);
+    URL url = webResourceLoader.getResource(uri);
+    if (url != null) {
+      serveResource(response, url);
+    } else {
+      handleResourceNotFound(response);
+    }
+  }
+
+  private String normalizeUri(HttpServletRequest request) {
+    return HttpUtil.getStrippedURI(request);
+  }
+
+  private void serveResource(HttpServletResponse response, URL url) {
+    // TODO lastModifiedDate, if-... ???
+    try (OutputStream output = response.getOutputStream()) {
+      Resources.copy(url, output);
+    } catch (IOException ex) {
+      LOG.warn("failed to serve resource: {}", url);
+      response.setStatus(HttpServletResponse.SC_INTERNAL_SERVER_ERROR);
+    }
+  }
+
+  private void handleResourceNotFound(HttpServletResponse response) {
+    response.setStatus(HttpServletResponse.SC_NOT_FOUND);
+  }
+}