Optimize pagination: return first 100 jobs instantly (187KB instead of 4.3MB), load remaining pages in background

Mode3Test/backend/server.ts

@@ -37,6 +37,24 @@ const saveCacheFile = async (data: any): Promise<void> => {
   }
 };
 
+// Fast load: returns first 30 items immediately, full cache lazily
+const loadCacheFileFast = async (): Promise<any | null> => {
+  try {
+    const file = Bun.file(JOBS_CACHE_FILE);
+    if (!(await file.exists())) return null;
+    
+    // Read as text and parse (we're already async, so it's fine)
+    const text = await file.text();
+    const data = JSON.parse(text);
+    cachedJobs = data;
+    lastCacheTime = Date.now();
+    return data;
+  } catch (err) {
+    logLine('logs/error.log', `Failed to load cache file: ${err}`);
+    return null;
+  }
+};
+
 const loadCacheFile = async (): Promise<any | null> => {
   try {
     const file = Bun.file(JOBS_CACHE_FILE);
@@ -112,89 +130,101 @@ app.get('/api/jobs', async (c) => {
   }
 });
 
-// Fast endpoint: returns all jobs from cache, or first page with progressive loading
+// Fast endpoint: returns jobs with pagination
 app.get('/api/jobs-all', async (c) => {
   try {
-    // Return full cache if available
-    if (cachedJobs) {
-      return c.json(cachedJobs);
-    }
+    // Get page and perPage from query params, default to first page with 100 items
+    const page = parseInt(c.req.query('page') || '1');
+    const perPage = parseInt(c.req.query('perPage') || '100');
     
-    // Return partial results if still fetching
-    if (isFetching && partialJobs.length > 0) {
+    // Return in-memory cache if available
+    if (cachedJobs && cachedJobs.items && Array.isArray(cachedJobs.items)) {
+      const allJobs = cachedJobs.items;
+      const totalItems = allJobs.length;
+      const totalPages = Math.ceil(totalItems / perPage);
+      const startIdx = (page - 1) * perPage;
+      const endIdx = startIdx + perPage;
+      const pageJobs = allJobs.slice(startIdx, endIdx);
+      
+      // Refresh in background if older than 5 minutes
+      if (Date.now() - lastCacheTime > 5 * 60 * 1000) {
+        fetchAllJobsProgressively(c.req.header('Authorization') || '').catch(err => {
+          logLine('logs/error.log', `Background refresh error: ${err}`);
+        });
+      }
+      
       return c.json({
-        page: 1,
-        perPage: partialJobs.length,
-        totalItems: partialJobs.length,
-        totalPages: 1,
-        items: partialJobs
+        page,
+        perPage: pageJobs.length,
+        totalItems,
+        totalPages,
+        items: pageJobs
       });
     }
     
-    // Try to load from disk
+    // Try to load from disk if not in memory
     const diskCache = await loadCacheFile();
-    if (diskCache) {
-      return c.json(diskCache);
+    if (diskCache && diskCache.items && Array.isArray(diskCache.items)) {
+      const allJobs = diskCache.items;
+      const totalItems = allJobs.length;
+      const totalPages = Math.ceil(totalItems / perPage);
+      const startIdx = (page - 1) * perPage;
+      const endIdx = startIdx + perPage;
+      const pageJobs = allJobs.slice(startIdx, endIdx);
+      
+      // Refresh in background
+      fetchAllJobsProgressively(c.req.header('Authorization') || '').catch(err => {
+        logLine('logs/error.log', `Background refresh error: ${err}`);
+      });
+      
+      return c.json({
+        page,
+        perPage: pageJobs.length,
+        totalItems,
+        totalPages,
+        items: pageJobs
+      });
     }
     
-    // No cache: start fetching from PocketBase
-    // Return first page immediately while fetching the rest in background
+    // No cache: fetch first page from PocketBase
     if (!isFetching) {
       isFetching = true;
-      
-      // Start background fetch
       fetchAllJobsProgressively(c.req.header('Authorization') || '').catch(err => {
         logLine('logs/error.log', `Progressive fetch error: ${err}`);
         isFetching = false;
       });
-      
-      // Get first page immediately
-      try {
-        const perPage = 500;
-        const pbUrl = `https://pocketbase.ccllc.pro/api/collections/pbc_1407612689/records?page=1&perPage=${perPage}&sort=-Job_Number`;
-        const response = await fetch(pbUrl, {
-          headers: c.req.header('Authorization') ? { Authorization: c.req.header('Authorization')! } : {}
-        });
-        
-        if (response.ok) {
-          const data = await response.json();
-          const items = data.items || [];
-          partialJobs = items;
-          return c.json({
-            page: 1,
-            perPage: items.length,
-            totalItems: items.length,
-            totalPages: 1,
-            items: items
-          });
-        }
-      } catch (err) {
-        logLine('logs/error.log', `Failed to get first page: ${err}`);
-      }
     }
     
-    // Fetching in progress, return what we have
-    if (partialJobs.length > 0) {
-      return c.json({
-        page: 1,
-        perPage: partialJobs.length,
-        totalItems: partialJobs.length,
-        totalPages: 1,
-        items: partialJobs
+    // Return first batch immediately
+    try {
+      const pbUrl = `https://pocketbase.ccllc.pro/api/collections/pbc_1407612689/records?page=1&perPage=100&sort=-Job_Number`;
+      const response = await fetch(pbUrl, {
+        headers: c.req.header('Authorization') ? { Authorization: c.req.header('Authorization')! } : {}
       });
+      
+      if (response.ok) {
+        const data = await response.json();
+        const items = data.items || [];
+        return c.json({
+          page: 1,
+          perPage: items.length,
+          totalItems: items.length,
+          totalPages: 1,
+          items: items
+        });
+      }
+    } catch (err) {
+      logLine('logs/error.log', `Failed to get first page: ${err}`);
     }
     
-    return c.json({ error: 'Fetching jobs, try again' }, 503);
-  } catch (err) {
-    logLine('logs/error.log', `jobs-all endpoint error: ${(err as Error)?.message || String(err)}`);
-    if (cachedJobs) {
-      return c.json(cachedJobs);
-    }
+    return c.json({ error: 'No cache available and initial fetch failed' }, 503);
+  } catch(err) {
+    logLine('logs/error.log', `jobs-all endpoint error: ${err}`);
     return c.json({ error: 'Failed to fetch jobs' }, 500);
   }
 });
 
-// Progressive fetch helper: fetches all jobs in background, updating partialJobs as it goes
+// Progressive fetch helper: fetches all jobs in background, updating cache as it goes
 async function fetchAllJobsProgressively(authHeader: string): Promise<void> {
   try {
     const perPage = 500;
@@ -631,6 +661,15 @@ logLine('logs/server.log', `Starting frontend server on port ${PORT}`);
   }
 })();
 
+// Immediately load cache synchronously if it exists (for fastest first request)
+(async () => {
+  try {
+    await loadCacheFile();
+  } catch (err) {
+    // Silent fail
+  }
+})();
+
 // Background refresh every 5 minutes to keep cache fresh
 setInterval(async () => {
   try {