From e6ccb9b66c0f7d4a091688d880ab950379fd6b1f Mon Sep 17 00:00:00 2001
From: reusedname <155286845+reusedname@users.noreply.github.com>
Date: Thu, 14 Nov 2024 23:16:42 +0500
Subject: [PATCH] basic debug servlet to print thread stacks

---
 .../ctbrec/recorder/server/DebugServlet.java  | 71 +++++++++++++++++++
 .../ctbrec/recorder/server/HttpServer.java    |  4 ++
 2 files changed, 75 insertions(+)
 create mode 100644 server/src/main/java/ctbrec/recorder/server/DebugServlet.java

diff --git a/server/src/main/java/ctbrec/recorder/server/DebugServlet.java b/server/src/main/java/ctbrec/recorder/server/DebugServlet.java
new file mode 100644
index 00000000..dfe776ee
--- /dev/null
+++ b/server/src/main/java/ctbrec/recorder/server/DebugServlet.java
@@ -0,0 +1,71 @@
+package ctbrec.recorder.server;
+
+import ctbrec.Config;
+import lombok.RequiredArgsConstructor;
+import lombok.extern.slf4j.Slf4j;
+import org.json.JSONObject;
+
+import javax.servlet.http.HttpServletRequest;
+import javax.servlet.http.HttpServletResponse;
+
+import java.io.PrintWriter;
+import java.io.StringWriter;
+import java.net.URLDecoder;
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
+import java.text.MessageFormat;
+
+import static java.nio.charset.StandardCharsets.UTF_8;
+import static javax.servlet.http.HttpServletResponse.*;
+
+@Slf4j
+public class DebugServlet extends AbstractCtbrecServlet {
+
+    public static final String BASE_URL = "/debug";
+    
+    private static final Pattern URL_PATTERN_DEBUG_STACK = Pattern.compile(BASE_URL + "/stack(/.*?)");
+    
+    public DebugServlet()
+    {}
+
+    @Override
+    protected void doGet(HttpServletRequest req, HttpServletResponse resp) {
+        String requestURI = req.getRequestURI().substring(req.getContextPath().length());
+        try {
+            // boolean authenticated = checkAuthentication(req, "");
+            // if (!authenticated) {
+            //     sendResponse(resp, SC_UNAUTHORIZED, HMAC_ERROR_DOCUMENT);
+            //     return;
+            // }
+
+            Matcher m;
+            if ((m = URL_PATTERN_DEBUG_STACK.matcher(requestURI)).matches()) {
+                String threadUrl = URLDecoder.decode(m.group(1), UTF_8);
+                
+                var stacks = Thread.getAllStackTraces();
+                var box = new Object() { String text = ""; };//stacks.toString();
+                
+                StringWriter sw = new StringWriter();
+                PrintWriter pw = new PrintWriter(sw);
+                // e.printStackTrace(pw);
+                
+                stacks.forEach((thread, stack) -> {
+                    box.text += String.format("%s:\n", thread.getName());
+                    var idx = 0;
+                    for (var s : stack) {
+                        box.text += String.format("[%d] %s\n", idx++, s.toString());
+                    }
+                });
+                
+                log.debug("Stacks Request {} - {}", threadUrl, stacks);
+                resp.setContentType("text/plain");
+                sendResponse(resp, SC_OK, box.text);
+            } else
+                sendResponse(resp, SC_NOT_FOUND, "");
+        } catch (Exception e) {
+            log.error(INTERNAL_SERVER_ERROR, e);
+            sendResponse(resp, SC_INTERNAL_SERVER_ERROR, INTERNAL_SERVER_ERROR);
+        }
+    }
+
+}
diff --git a/server/src/main/java/ctbrec/recorder/server/HttpServer.java b/server/src/main/java/ctbrec/recorder/server/HttpServer.java
index 7a4452ed..0b507503 100644
--- a/server/src/main/java/ctbrec/recorder/server/HttpServer.java
+++ b/server/src/main/java/ctbrec/recorder/server/HttpServer.java
@@ -258,6 +258,10 @@ public class HttpServer {
             ModelServlet modelServlet = new ModelServlet(config);
             holder = new ServletHolder(modelServlet);
             defaultContext.addServlet(holder, ModelServlet.BASE_URL + "/*");
+            
+            DebugServlet debugServlet = new DebugServlet();
+            holder = new ServletHolder(debugServlet);
+            defaultContext.addServlet(holder, DebugServlet.BASE_URL + "/*");
 
             if (this.config.getSettings().webinterface) {
                 startWebInterface(defaultContext, basicAuthContext);