added fromtpage

src/main/java/de/srsoftware/widerhall/web/TemplateServlet.java

@@ -0,0 +1,57 @@
+package de.srsoftware.widerhall.web;
+
+import de.srsoftware.widerhall.Configuration;
+import org.stringtemplate.v4.STGroup;
+import org.stringtemplate.v4.STRawGroupDir;
+
+import javax.servlet.http.HttpServlet;
+import javax.servlet.http.HttpServletResponse;
+import java.io.File;
+import java.io.IOException;
+import java.nio.file.Files;
+import java.util.Map;
+
+import static de.srsoftware.widerhall.Util.t;
+
+public abstract class TemplateServlet extends HttpServlet {
+    private STGroup templates;
+    private final String baseDir;
+
+    public TemplateServlet(){
+        var config = Configuration.instance();
+        baseDir = config.baseDir();
+        loadTemplates();
+    }
+
+    protected String loadFile(String filename, HttpServletResponse resp) {
+        var path = String.join(File.separator,baseDir,"static",filename);
+        var file = new File(path);
+        if (!file.exists()) return t("File {} does not exist!",filename);
+        try {
+            var content = Files.readString(file.toPath());
+            resp.getWriter().println(content);
+        } catch (IOException e) {
+            return t("Failed to load file '{}'!",filename);
+        }
+        return null;
+    }
+
+    protected String loadTemplate(String path, Map<String, ? extends Object> data, HttpServletResponse resp) {
+        var template = templates.getInstanceOf(path);
+        if (template != null){
+            try {
+                template.add("data",data);
+                resp.getWriter().println(template.render());
+                return null;
+            } catch (IOException e) {
+                return t("Failed to load template '{}'",path);
+            }
+        }
+        return t("No template for path '{}'!",path);
+    }
+
+    protected void loadTemplates() {
+        var templateDir = String.join(File.separator,baseDir,"static","templates");
+        templates = new STRawGroupDir(templateDir,'«','»');
+    }
+}