improvement

backend/database/urls.json

@@ -1,15 +1,24 @@
 [
     "cloudflare.com",
-    "postgresql.org",
+    "example.invalid",
-    "github.com",
-    "mozilla.org",
-    "amazon.com",
     "google.com",
+    "myfakewebsite123.xyz",
+    "postgresql.org",
+    "notarealdomain.test",
+    "github.com",
     "docker.com",
-    "wikipedia.org",
+    "invalid-site-999.com",
-    "duckduckgo.com",
+    "mozilla.org",
-    "nodejs.org",
-    "amns.in",
     "amazon.in",
-    "amdocs.com"
+    "thisdoesnotexistabc123.com",
+    "nodejs.org",
+    "amdocs.com",
+    "fake-company-domain.org",
+    "wikipedia.org",
+    "nonexistentdomain987654.net",
+    "duckduckgo.com",
+    "amazon.com",
+    "amns.in",
+    "missingwebsite.fake",
+    "randominvaliddomain12345.io"
 ]

backend/models/db_store_controller.js

@@ -4,6 +4,12 @@ const url_path = path.join(__dirname, "../database", "db.json");
 
 const StoreRecord = async (urlRecord) => {
   try {
+    try {
+      await fs.access(url_path);
+    } catch {
+      await fs.writeFile(url_path, "[]");
+    }
+
     const rawData = await fs.readFile(url_path, "utf8");
     const data = JSON.parse(rawData);
 

backend/web_socket_server.js

@@ -6,7 +6,6 @@ const { StoreRecord } = require("./models/db_store_controller");
 const { checkUrl } = require("./models/health_status_controller");
 
 const { init, broadcast } = require("./utils/utils");
-// const urlPath = "./database/urls.json";
 const urlPath = path.join(__dirname, "database", "urls.json");
 dotenv.config();
 
@@ -35,11 +34,17 @@ const checkAllUrl = async (Store) => {
 async function setupWebSocket(wss) {
   init(wss);
   let Store = [];
-  checkAllUrl(Store);
+  wss.on("connection", (ws) => {
-  setInterval(async () => {
-    Store = [];
     checkAllUrl(Store);
-  }, 2000);
+  });
+
+  setInterval(
+    async () => {
+      Store = [];
+      checkAllUrl(Store);
+    },
+    process.env.TIME || 60 * 1000,
+  );
 }
 
 module.exports = { setupWebSocket };

frontend/index.html

@@ -15,6 +15,7 @@
             <h1>URL HEALTH MONITOR</h1>
 
             <h4>WebSocket: <span id="websocket_status">Connecting...</span></h4>
+            <h4>Page will fetch latest update every 60 second </h4>
 
             <h4 id="status"></h4>
         </div>

frontend/scripts.js

@@ -1,23 +1,22 @@
 const tbody = document.getElementById("content-display");
 
 async function init() {
-    try {
+  try {
-        const response = await fetch("/api/url");
+    const response = await fetch("/api/url");
 
-        if (!response.ok) {
+    if (!response.ok) {
-            throw new Error(`HTTP ${response.status}`);
+      throw new Error(`HTTP ${response.status}`);
-        }
+    }
 
-        const urls = await response.json();
+    const urls = await response.json();
 
-        urls.forEach((url) => {
+    urls.forEach((url) => {
+      const id = url.replace(/[^a-zA-Z0-9]/g, "_");
 
-            const id = url.replace(/[^a-zA-Z0-9]/g, "_");
+      const row = document.createElement("tr");
+      row.id = id;
 
-            const row = document.createElement("tr");
+      row.innerHTML = `
-            row.id = id;
-
-            row.innerHTML = `
                 <td>${url}</td>
                 <td class="status">Waiting...</td>
                 <td class="statusCode">-</td>
@@ -25,12 +24,11 @@ async function init() {
                 <td class="error">-</td>
             `;
 
-            tbody.appendChild(row);
+      tbody.appendChild(row);
-        });
+    });
-
+  } catch (err) {
-    } catch (err) {
+    console.error(err);
-        console.error(err);
+  }
-    }
 }
 
 document.addEventListener("DOMContentLoaded", init);
@@ -43,60 +41,59 @@ console.log(socket);
 const websocket_status = document.getElementById("websocket_status");
 
 socket.onopen = () => {
-    websocket_status.textContent = "Connected";
+  websocket_status.textContent = "Connected";
 };
-let counter = 0
+let counter = 0;
 socket.onmessage = (event) => {
-    // console.log(counter)
+  // console.log(counter)
-    const data = JSON.parse(event.data);
+  const data = JSON.parse(event.data);
-    if (data.type === "checking") {
+  if (data.type === "checking") {
-        counter = counter + 1
+    counter = counter + 1;
-        console.log(counter)
+    document.getElementById("status").textContent =
-        document.getElementById("status").textContent = "Refreshed " + counter + " Times";
+      "Refreshed " + counter + " Times";
-        return;
+    return;
-    }
+  }
 
+  const id = data.url.replace(/[^a-zA-Z0-9]/g, "_");
+  const row = document.getElementById(id);
+  if (!row) return;
 
-    const id = data.url.replace(/[^a-zA-Z0-9]/g, "_");
+  row.querySelector(".status").textContent = data.status;
-    const row = document.getElementById(id);
+  row.querySelector(".statusCode").textContent = data.statusCode;
-    if (!row) return;
+  row.querySelector(".responseTime").textContent =
-
+    data.responseTime != null ? `${data.responseTime} ms` : "-";
-    row.querySelector(".status").textContent = data.status;
+  row.querySelector(".error").textContent = data.error || "-";
-    row.querySelector(".statusCode").textContent = data.statusCode;
-    row.querySelector(".responseTime").textContent = data.responseTime != null ? `${data.responseTime} ms` : "-";
-    row.querySelector(".error").textContent = data.error || "-";
 };
 
-
 socket.onclose = () => {
-    websocket_status.textContent = "Disconnected";
+  websocket_status.textContent = "Disconnected";
 };
 
 document.getElementById("addBtn").addEventListener("click", async () => {
-    const url = document.getElementById("urlInput").value.trim();
+  const url = document.getElementById("urlInput").value.trim();
-    if (!url) return;
+  if (!url) return;
 
-    const response = await fetch("/api/url/register", {
+  const response = await fetch("/api/url/register", {
-        method: "POST",
+    method: "POST",
-        headers: { "Content-Type": "application/json" },
+    headers: { "Content-Type": "application/json" },
-        body: JSON.stringify({ url })
+    body: JSON.stringify({ url }),
-    });
+  });
 
-    if (response.ok) {
+  if (response.ok) {
-        document.getElementById("urlInput").value = "";
+    document.getElementById("urlInput").value = "";
 
-        const id = url.replace(/[^a-zA-Z0-9]/g, "_");
+    const id = url.replace(/[^a-zA-Z0-9]/g, "_");
-        if (!document.getElementById(id)) {
+    if (!document.getElementById(id)) {
-            const row = document.createElement("tr");
+      const row = document.createElement("tr");
-            row.id = id;
+      row.id = id;
-            row.innerHTML = `
+      row.innerHTML = `
                 <td>${url}</td>
                 <td class="status">Waiting...</td>
                 <td class="statusCode">-</td>
                 <td class="responseTime">-</td>
                 <td class="error">-</td>
             `;
-            tbody.appendChild(row);
+      tbody.appendChild(row);
-        }
     }
+  }
 });

package.json

@@ -2,10 +2,9 @@
   "name": "uptime_monitor",
   "version": "1.0.0",
   "description": "A lightweight **URL Health Monitoring** application built with **Node.js, Express, WebSocket, Axios, and Docker**. The application periodically checks the health of registered URLs and updates the frontend in real time using WebSockets.",
-  "main": "app.js",
+  "main": "./backend/app.js",
   "scripts": {
-    "start": "node backend/app.js",
+    "start": "node backend/app.js"
-    "test": "echo \"Error: no test specified\" && exit 1"
   },
   "keywords": [],
   "author": "Akshay Vadher",