fix: proxy dashboard through Netlify function

netlify.toml

@@ -4,3 +4,12 @@
 
 [build.environment]
   NODE_VERSION = "22"
+
+[functions]
+  directory = "netlify/functions"
+  node_bundler = "esbuild"
+
+[[redirects]]
+  from = "/api/dashboard"
+  to = "/.netlify/functions/dashboard"
+  status = 200

netlify/functions/dashboard.js

@@ -0,0 +1,68 @@
+const DEFAULT_DASHBOARD_URL = 'https://dashboard.informatika.untan.ac.id/index.php?penelitian';
+const CACHE_TTL_MS = 5 * 60 * 1000;
+
+let dashboardCache = {
+  html: '',
+  timestamp: 0,
+};
+
+function getDashboardUrl() {
+  return process.env.DASHBOARD_TARGET_URL || DEFAULT_DASHBOARD_URL;
+}
+
+function response(statusCode, body, extraHeaders = {}) {
+  return {
+    statusCode,
+    headers: {
+      'Content-Type': 'text/html; charset=utf-8',
+      'Cache-Control': 'public, max-age=60, stale-while-revalidate=300',
+      ...extraHeaders,
+    },
+    body,
+  };
+}
+
+exports.handler = async () => {
+  const now = Date.now();
+
+  if (dashboardCache.html && now - dashboardCache.timestamp < CACHE_TTL_MS) {
+    return response(200, dashboardCache.html, { 'X-Cache': 'HIT' });
+  }
+
+  const controller = new AbortController();
+  const timeoutId = setTimeout(() => controller.abort(), 12000);
+
+  try {
+    const dashboardResponse = await fetch(getDashboardUrl(), {
+      signal: controller.signal,
+      headers: {
+        'User-Agent': 'Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/120.0 Safari/537.36',
+      },
+    });
+
+    if (!dashboardResponse.ok) {
+      throw new Error(`HTTP_ERROR_${dashboardResponse.status}`);
+    }
+
+    const html = await dashboardResponse.text();
+    dashboardCache = { html, timestamp: Date.now() };
+
+    return response(200, html, { 'X-Cache': 'MISS' });
+  } catch (error) {
+    if (dashboardCache.html) {
+      return response(200, dashboardCache.html, { 'X-Cache': 'STALE' });
+    }
+
+    return {
+      statusCode: 502,
+      headers: {
+        'Content-Type': 'text/plain; charset=utf-8',
+      },
+      body: error && error.name === 'AbortError'
+        ? 'DASHBOARD_FETCH_TIMEOUT'
+        : 'DASHBOARD_FETCH_FAILED',
+    };
+  } finally {
+    clearTimeout(timeoutId);
+  }
+};