feat: launch a lazy per-run browser for the fallback scraper

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_013gwc3aCiyQxmCWQke8RvEz

server.js

@@ -8,6 +8,7 @@ const {
   recordCheckSuccess, recordCheckFailure,
 } = require('./src/db');
 const { fetchAndExtractPrice } = require('./src/scraper');
+const { launchBrowser, fetchAndExtractPriceViaBrowser } = require('./src/browserScraper');
 const { createTransport, sendPriceChangeEmail } = require('./src/mailer');
 const { checkAllProducts } = require('./src/checkProducts');
 const { start: startScheduler } = require('./src/scheduler');
@@ -36,10 +37,22 @@ function summarize(results) {
   return parts.length > 0 ? parts.join(' ') : 'geen producten';
 }
 
-function runCheck() {
+async function runCheck() {
   const products = listProducts(db);
+  let browserPromise = null;
+  function getBrowser() {
+    if (!browserPromise) {
+      browserPromise = launchBrowser();
+    }
+    return browserPromise;
+  }
+  try {
     const deps = {
       fetchAndExtractPrice,
+      fetchAndExtractPriceViaBrowser: async (url) => {
+        const browser = await getBrowser();
+        return fetchAndExtractPriceViaBrowser(browser, url);
+      },
       sendMail: (payload) => sendPriceChangeEmail(transport, {
         from: process.env.SMTP_FROM,
         to: process.env.NOTIFY_EMAIL,
@@ -49,11 +62,18 @@ function runCheck() {
       recordCheckSuccess: (id, data) => recordCheckSuccess(db, id, data),
       now: () => new Date().toISOString(),
     };
-  return checkAllProducts(products, deps).then((results) => {
+    const results = await checkAllProducts(products, deps);
     console.log(`[check] ${products.length} product(en) gecontroleerd: ${summarize(results)}`);
     return results;
+  } finally {
+    if (browserPromise) {
+      const browser = await browserPromise;
+      await browser.close().catch((err) => {
+        console.error(`[check] kon de browser niet netjes sluiten: ${err && err.message}`);
       });
     }
+  }
+}
 
 startScheduler(runCheck);