if the feed has never been fetched, save the last valid item

packages/rss-handler/src/index.ts

@@ -12,6 +12,11 @@ interface RssFeedRequest {
   lastFetchedAt: string
 }
 
+interface ValidRssFeedItem {
+  link: string
+  isoDate: string
+}
+
 function isRssFeedRequest(body: any): body is RssFeedRequest {
   return (
     'subscriptionId' in body && 'feedUrl' in body && 'lastFetchedAt' in body
@@ -78,6 +83,35 @@ const sendUpdateSubscriptionMutation = async (
   }
 }
 
+const createSavingItemTask = async (
+  userId: string,
+  feedUrl: string,
+  item: ValidRssFeedItem
+) => {
+  const input = {
+    userId,
+    source: 'rss-feeder',
+    url: item.link,
+    saveRequestId: '',
+    labels: [{ name: 'RSS', color: '#f26522' }],
+    rssFeedUrl: feedUrl,
+    savedAt: item.isoDate,
+    publishedAt: item.isoDate,
+  }
+
+  try {
+    console.log('Creating task', input.url)
+    // save page
+    const task = await createCloudTask(CONTENT_FETCH_URL, input)
+    console.log('Created task', task)
+
+    return !!task
+  } catch (error) {
+    console.error('Error while creating task', error)
+    return false
+  }
+}
+
 dotenv.config()
 Sentry.GCPFunction.init({
   dsn: process.env.SENTRY_DSN,
@@ -121,13 +155,15 @@ export const rssHandler = Sentry.GCPFunction.wrapHttpFunction(
       const { feedUrl, subscriptionId, lastFetchedAt } = req.body
       console.log('Processing feed', feedUrl, lastFetchedAt)
 
+      let lastItemFetchedAt: Date | null = null
+      let lastValidItem: ValidRssFeedItem | null = null
+
       // fetch feed
       const feed = await parser.parseURL(feedUrl)
-      const newFetchedAt = new Date()
-      console.log('Fetched feed', feed.title, newFetchedAt)
+      console.log('Fetched feed', feed.title, new Date())
 
       // save each item in the feed
-      for await (const item of feed.items) {
+      for (const item of feed.items) {
         console.log('Processing feed item', item.link, item.isoDate)
 
         if (!item.link || !item.isoDate) {
@@ -135,6 +171,12 @@ export const rssHandler = Sentry.GCPFunction.wrapHttpFunction(
           continue
         }
 
+        // remember the last valid item
+        lastValidItem = {
+          link: item.link,
+          isoDate: item.isoDate,
+        }
+
         // skip old items and items that were published before 24h
         const publishedAt = new Date(item.isoDate)
         if (
@@ -145,32 +187,52 @@ export const rssHandler = Sentry.GCPFunction.wrapHttpFunction(
           continue
         }
 
-        const input = {
+        const created = await createSavingItemTask(
           userId,
-          source: 'rss-feeder',
-          url: item.link,
-          saveRequestId: '',
-          labels: [{ name: 'RSS', color: '#f26522' }],
-          rssFeedUrl: feedUrl,
-          savedAt: publishedAt,
-          publishedAt,
+          feedUrl,
+          lastValidItem
+        )
+        if (!created) {
+          console.error('Failed to create task for feed item', item.link)
+          continue
         }
 
-        try {
-          console.log('Creating task', input.url)
-          // save page
-          const task = await createCloudTask(CONTENT_FETCH_URL, input)
-          console.log('Created task', task)
-        } catch (error) {
-          console.error('Error while creating task', error)
+        // remember the last item fetched at
+        if (!lastItemFetchedAt || publishedAt > lastItemFetchedAt) {
+          lastItemFetchedAt = publishedAt
         }
       }
 
+      // no items saved
+      if (!lastItemFetchedAt) {
+        // the feed has been fetched before, no new valid items found
+        if (lastFetchedAt || !lastValidItem) {
+          console.log('No new valid items found')
+          return res.send('ok')
+        }
+
+        // the feed has never been fetched, save the last valid item
+        const created = await createSavingItemTask(
+          userId,
+          feedUrl,
+          lastValidItem
+        )
+        if (!created) {
+          console.error(
+            'Failed to create task for feed item',
+            lastValidItem.link
+          )
+          return res.status(500).send('INTERNAL_SERVER_ERROR')
+        }
+
+        lastItemFetchedAt = new Date(lastValidItem.isoDate)
+      }
+
       // update subscription lastFetchedAt
       const updatedSubscription = await sendUpdateSubscriptionMutation(
         userId,
         subscriptionId,
-        newFetchedAt
+        lastItemFetchedAt
       )
       console.log('Updated subscription', updatedSubscription)