From 3e5409f4ce4560e62a58f2dd90751b13c8fb108d Mon Sep 17 00:00:00 2001
From: Yash Khare <khareyash05@gmail.com>
Date: Wed, 27 May 2026 16:29:06 +0530
Subject: [PATCH] feat(spring-mysql-redis): add endpoint to trigger
 COM_STMT_RESET

Adds GET /api/todos/stmt-reset/{id}/{n} which re-executes a server-side
prepared statement n times on the same connection. Combined with the new
JDBC URL flags (useServerPrepStmts, cachePrepStmts, useCursorFetch),
MySQL Connector/J 8.x emits COM_STMT_RESET between re-executions, which
exercises the synthetic-OK fallback path added in keploy/keploy#4217 so
record/replay can be validated.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
---
 .../todo/controller/TodoController.java       | 55 +++++++++++++++++++
 .../src/main/resources/application.properties |  2 +-
 2 files changed, 56 insertions(+), 1 deletion(-)

diff --git a/spring-mysql-redis/src/main/java/org/example/todo/controller/TodoController.java b/spring-mysql-redis/src/main/java/org/example/todo/controller/TodoController.java
index ad0c3b92..c7e1dd25 100644
--- a/spring-mysql-redis/src/main/java/org/example/todo/controller/TodoController.java
+++ b/spring-mysql-redis/src/main/java/org/example/todo/controller/TodoController.java
@@ -6,7 +6,15 @@
 import org.springframework.http.ResponseEntity;
 import org.springframework.web.bind.annotation.*;
 
+import javax.sql.DataSource;
+import java.sql.Connection;
+import java.sql.PreparedStatement;
+import java.sql.ResultSet;
+import java.sql.SQLException;
+import java.util.ArrayList;
+import java.util.HashMap;
 import java.util.List;
+import java.util.Map;
 import java.util.Optional;
 
 @RestController
@@ -16,6 +24,9 @@ public class TodoController {
     @Autowired
     private TodoService todoService;
 
+    @Autowired
+    private DataSource dataSource;
+
     @GetMapping
     public List<Todo> getAllTodos() {
         return todoService.findAll();
@@ -52,4 +63,48 @@ public ResponseEntity<Void> deleteTodo(@PathVariable Long id) {
         todoService.deleteById(id);
         return ResponseEntity.ok().build();
     }
+
+    /**
+     * Re-executes a server-side prepared statement {@code n} times on the same
+     * connection. With {@code useServerPrepStmts=true} and
+     * {@code useCursorFetch=true} (set in application.properties) plus a
+     * non-zero fetchSize, MySQL Connector/J 8.x sends a COM_STMT_RESET packet
+     * between re-executions to clear the cursor state. This endpoint exists to
+     * exercise that code path so Keploy record/replay can capture and match
+     * COM_STMT_RESET frames.
+     */
+    @GetMapping("/stmt-reset/{id}/{n}")
+    public ResponseEntity<Map<String, Object>> stmtReset(@PathVariable Long id,
+                                                         @PathVariable int n) throws SQLException {
+        List<Map<String, Object>> rows = new ArrayList<>();
+        String sql = "SELECT id, title, description, completed FROM todo WHERE id = ?";
+
+        try (Connection conn = dataSource.getConnection();
+             PreparedStatement ps = conn.prepareStatement(sql)) {
+
+            // Forces server-side cursor (with useCursorFetch=true), which is
+            // what causes Connector/J to emit COM_STMT_RESET on re-execution.
+            ps.setFetchSize(1);
+
+            for (int i = 0; i < n; i++) {
+                ps.setLong(1, id);
+                try (ResultSet rs = ps.executeQuery()) {
+                    if (rs.next()) {
+                        Map<String, Object> row = new HashMap<>();
+                        row.put("id", rs.getLong("id"));
+                        row.put("title", rs.getString("title"));
+                        row.put("description", rs.getString("description"));
+                        row.put("completed", rs.getBoolean("completed"));
+                        rows.add(row);
+                    }
+                }
+            }
+        }
+
+        Map<String, Object> response = new HashMap<>();
+        response.put("iterations", n);
+        response.put("rowsFetched", rows.size());
+        response.put("results", rows);
+        return ResponseEntity.ok(response);
+    }
 }
diff --git a/spring-mysql-redis/src/main/resources/application.properties b/spring-mysql-redis/src/main/resources/application.properties
index 776a0c97..e73bd8dc 100644
--- a/spring-mysql-redis/src/main/resources/application.properties
+++ b/spring-mysql-redis/src/main/resources/application.properties
@@ -1,5 +1,5 @@
 # MySQL Configuration
-spring.datasource.url=jdbc:mysql://localhost:3306/todoapp?useSSL=false&serverTimezone=UTC&allowPublicKeyRetrieval=true
+spring.datasource.url=jdbc:mysql://localhost:3306/todoapp?useSSL=false&serverTimezone=UTC&allowPublicKeyRetrieval=true&useServerPrepStmts=true&cachePrepStmts=true&useCursorFetch=true
 spring.datasource.username=yourusername
 spring.datasource.password=yourpassword
 spring.datasource.driver-class-name=com.mysql.cj.jdbc.Driver