first commit

config/database.js

@@ -0,0 +1,83 @@
+const mongoose = require("mongoose");
+
+const actionSchema = new mongoose.Schema({
+  updated: Number,
+});
+const Action = mongoose.model("Action", actionSchema);
+
+const userSchema = new mongoose.Schema({ name: String });
+
+async function updateAction() {
+  try {
+    await Action.updateOne({}, { $set: { updated: 1 } }, { upsert: true });
+
+    console.log("✅ Cập nhật thành công");
+  } catch (err) {
+    console.error("❌ Lỗi cập nhật:", err);
+  }
+}
+
+const connectDB = async () => {
+  try {
+    const conn = await mongoose.connect(process.env.MONGODB_URI);
+    console.log(`✅ MongoDB Connected:[ ${conn.connection.host} ]`);
+
+    // Lấy db sau khi connect thành công
+    const db = mongoose.connection.db;
+
+    // admin is the database admin interface used to run server commands
+    const admin = db.admin();
+    const isMaster = await admin.command({ isMaster: 1 });
+
+    // Only create a ChangeStream when connected to a replica set.
+    // On standalone servers the $changeStream aggregation stage isn't supported
+    // and attempting to watch() will emit an 'error' event that can crash the
+    // process if not handled. Guard and add defensive error handling.
+    if (isMaster && isMaster.setName) {
+      try {
+        const changeStream = db.watch([
+          {
+            $match: {
+              "ns.coll": { $ne: "actions" }, // bỏ qua collection "actions"
+            },
+          },
+        ]);
+
+        changeStream.on("change", async (change) => {
+          try {
+            console.log("📢 Change detected:", change);
+            await updateAction();
+          } catch (e) {
+            console.error("Error handling change event:", e);
+          }
+        });
+
+        // Defensive: listen for errors so they don't bubble as unhandled
+        changeStream.on("error", (err) => {
+          console.warn(
+            "⚠️ ChangeStream error — disabling change stream:",
+            err && err.message ? err.message : err,
+          );
+          try {
+            changeStream.close();
+          } catch (e) {
+            /* ignore */
+          }
+        });
+      } catch (e) {
+        // If watch() throws synchronously (older drivers/servers) skip it.
+        console.log(
+          "ℹ️ ChangeStream not initialized (watch() failed):",
+          e.message || e,
+        );
+      }
+    } else {
+      console.log("ℹ️ ChangeStream skipped (no replica set detected)");
+    }
+  } catch (error) {
+    console.error(`Error: ${error.message}`);
+    process.exit(1);
+  }
+};
+
+module.exports = connectDB;