allow changing context path, by using a template for index.html

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

@@ -0,0 +1,61 @@
+package sonia.scm;
+
+import com.google.common.annotations.VisibleForTesting;
+import sonia.scm.template.Template;
+import sonia.scm.template.TemplateEngine;
+import sonia.scm.template.TemplateEngineFactory;
+
+import javax.inject.Inject;
+import javax.servlet.http.HttpServletRequest;
+import javax.servlet.http.HttpServletResponse;
+import java.io.IOException;
+import java.io.Writer;
+
+/**
+ * This dispatcher renders the /index.mustache template, which is merged in from the scm-ui package.
+ *
+ * @since 2.0.0
+ */
+public class TemplatingPushStateDispatcher implements PushStateDispatcher {
+
+  @VisibleForTesting
+  static final String TEMPLATE = "/index.mustache";
+
+  private final TemplateEngine templateEngine;
+
+  @Inject
+  public TemplatingPushStateDispatcher(TemplateEngineFactory templateEngineFactory) {
+    this(templateEngineFactory.getDefaultEngine());
+  }
+
+  @VisibleForTesting
+  TemplatingPushStateDispatcher(TemplateEngine templateEngine) {
+    this.templateEngine = templateEngine;
+  }
+
+  @Override
+  public void dispatch(HttpServletRequest request, HttpServletResponse response, String uri) throws IOException {
+    response.setContentType("text/html");
+    response.setCharacterEncoding("UTF-8");
+
+    Template template = templateEngine.getTemplate(TEMPLATE);
+    try (Writer writer = response.getWriter()) {
+      template.execute(writer, new IndexHtmlModel(request));
+    }
+  }
+
+  @VisibleForTesting
+  static class IndexHtmlModel {
+
+    private final HttpServletRequest request;
+
+    private IndexHtmlModel(HttpServletRequest request) {
+      this.request = request;
+    }
+
+    public String getContextPath() {
+      return request.getContextPath();
+    }
+
+  }
+}