From 1a64b540466d03867af779ecf168442da3241467 Mon Sep 17 00:00:00 2001
From: Alicia Sykes <sykes.alicia@gmail.com>
Date: Mon, 14 Jun 2021 20:42:02 +0100
Subject: [PATCH] Wrote server functions for checking uptime

---
 server.js        | 14 ++++++++--
 services/ping.js | 66 ++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 78 insertions(+), 2 deletions(-)
 create mode 100644 services/ping.js

diff --git a/server.js b/server.js
index 9bdbca41..d1401c47 100644
--- a/server.js
+++ b/server.js
@@ -9,6 +9,8 @@ const os = require('os');
 
 require('./src/utils/ConfigValidator');
 
+const pingUrl = require('./services/ping');
+
 const isDocker = !!process.env.IS_DOCKER;
 
 /* Checks env var for port. If undefined, will use Port 80 for Docker, or 4000 for metal */
@@ -64,8 +66,16 @@ const printWelcomeMessage = () => {
 
 try {
   connect()
-    .use(serveStatic(`${__dirname}/dist`))
-    .use(serveStatic(`${__dirname}/public`, { index: 'default.html' }))
+    .use(serveStatic(`${__dirname}/dist`)) /* Serves up the main built application to the root */
+    .use(serveStatic(`${__dirname}/public`, { index: 'default.html' })) /* During build, a custom page will be served */
+    .use('/ping', (req, res) => { /* This root returns the status of a given service - used for uptime monitoring */
+      try {
+        pingUrl(req.url, async (results) => {
+          await res.end(results);
+        });
+        // next();
+      } catch (e) { console.warn(`Error running ping check for ${req.url}\n`, e); }
+    })
     .listen(port, () => {
       try { printWelcomeMessage(); } catch (e) { console.log('Dashy is Starting...'); }
     });
diff --git a/services/ping.js b/services/ping.js
new file mode 100644
index 00000000..43e5caa4
--- /dev/null
+++ b/services/ping.js
@@ -0,0 +1,66 @@
+/**
+ * This file contains the Node.js code, used for the optional status check feature
+ * It accepts a single url parameter, and will make an empty GET request to that
+ * endpoint, and then resolve the response status code, time taken, and short message 
+ */
+const axios = require('axios').default;
+
+/* Determines if successful from the HTTP response code */
+const getResponseType = (code) => {
+  if (Number.isNaN(code)) return false;
+  const numericCode = parseInt(code, 10);
+  return (numericCode >= 200 && numericCode <= 302);
+};
+
+/* Makes human-readable response text for successful check */
+const makeMessageText = (data) => `${data.successStatus ? '✅' : '⚠️'} `
+  + `${data.serverName || 'Server'} responded with `
+  + `${data.statusCode} - ${data.statusText}. `
+  + `\n⏱️Took ${data.timeTaken} ms`;
+
+/* Makes human-readable response text for failed check */
+const makeErrorMessage = (data) => `❌ Service Unavailable: ${data.hostname || 'Server'} `
+  + `resulted in ${data.code || 'a fatal error'} ${data.errno ? `(${data.errno})` : ''}`;
+
+const makeErrorMessage2 = (data) => `❌ Service Error - `
+  + `${data.status} - ${data.statusText}`;
+
+/* Kicks of a HTTP request, then formats and renders results */
+const makeRequest = (url, render) => {
+  const startTime = new Date();
+  axios.get(url)
+    .then((response) => {
+      const statusCode = response.status;
+      const { statusText } = response;
+      const successStatus = getResponseType(statusCode);
+      const serverName = response.request.socket.servername;
+      const timeTaken = (new Date() - startTime);
+      const results = {
+        statusCode, statusText, serverName, successStatus, timeTaken,
+      };
+      const messageText = makeMessageText(results);
+      results.message = messageText;
+      return results;
+    })
+    .catch((error) => {
+      render(JSON.stringify({
+        successStatus: false,
+        message: error.response ? makeErrorMessage2(error.response) : makeErrorMessage(error),
+      }));
+    }).then((results) => {
+      render(JSON.stringify(results));
+    });
+};
+
+/* Main function, will check if a URL present, and call function */
+module.exports = (params, render) => {
+  if (!params || !params.includes('=')) {
+    render(JSON.stringify({
+      success: false,
+      message: '❌ Malformed URL',
+    }));
+  } else {
+    const url = params.split('=')[1];
+    makeRequest(url, render);
+  }
+};