Update user feed each hour and get feed from cache doc.

firestore.rules

@@ -34,6 +34,10 @@ service cloud.firestore {
       allow create: if userId == request.auth.uid;
     }
 
+    match /private-users/{userId}/cache/feed {
+      allow read: if userId == request.auth.uid || isAdmin();
+    }
+
     match /contracts/{contractId} {
       allow read;
       allow update: if request.resource.data.diff(resource.data).affectedKeys()

functions/src/index.ts

@@ -21,8 +21,8 @@ export * from './unsubscribe'
 export * from './update-contract-metrics'
 export * from './update-user-metrics'
 export * from './update-recommendations'
+export * from './update-user-feed'
 export * from './backup-db'
 export * from './change-user-info'
 export * from './market-close-emails'
 export * from './add-liquidity'
-export * from './get-feed'

functions/src/on-view.ts

@@ -12,13 +12,13 @@ export const onView = functions.firestore
     const { contractId, timestamp } = snapshot.data() as View
 
     await firestore
-      .doc(`private-users/${userId}/cached/viewCounts`)
+      .doc(`private-users/${userId}/cache/viewCounts`)
       .set(
         { [contractId]: admin.firestore.FieldValue.increment(1) },
         { merge: true }
       )
 
     await firestore
-      .doc(`private-users/${userId}/cached/lastViewTime`)
+      .doc(`private-users/${userId}/cache/lastViewTime`)
       .set({ [contractId]: timestamp }, { merge: true })
   })

functions/src/update-recommendations.ts

@@ -39,7 +39,7 @@ export const updateUserRecommendations = async (
     ),
 
     getValue<{ [contractId: string]: number }>(
-      firestore.doc(`private-users/${user.id}/cached/viewCounts`)
+      firestore.doc(`private-users/${user.id}/cache/viewCounts`)
     ),
 
     getValues<ClickEvent>(
@@ -53,7 +53,7 @@ export const updateUserRecommendations = async (
   const contractScores = getContractScores(contracts, wordScores)
 
   const cachedCollection = firestore.collection(
-    `private-users/${user.id}/cached`
+    `private-users/${user.id}/cache`
   )
   await cachedCollection.doc('wordScores').set(wordScores)
   await cachedCollection.doc('contractScores').set(contractScores)

functions/src/update-user-feed.ts

@@ -13,19 +13,18 @@ import {
 } from '../../common/calculate'
 import { Bet } from '../../common/bet'
 import { Comment } from '../../common/comment'
+import { User } from '../../common/user'
+import { batchedWaitAll } from '../../common/util/promise'
 
 const firestore = admin.firestore()
 
 const MAX_FEED_CONTRACTS = 60
 
-export const getFeed = functions
+export const updateUserFeed = functions.pubsub
-  .runWith({ minInstances: 1 })
+  .schedule('every 60 minutes')
-  .https.onCall(async (_data, context) => {
+  .onRun(async () => {
-    const userId = context?.auth?.uid
-    if (!userId) return { status: 'error', message: 'Not authorized' }
-
     // Get contracts bet on or created in last week.
-    const contractsPromise = Promise.all([
+    const contracts = await Promise.all([
       getValues<Contract>(
         firestore
           .collection('contracts')
@@ -46,59 +45,59 @@ export const getFeed = functions
       return combined.filter((c) => (c.closeTime ?? Infinity) > Date.now())
     })
 
-    const userCacheCollection = firestore.collection(
+    const users = await getValues<User>(firestore.collection('users'))
-      `private-users/${userId}/cached`
-    )
-    const [recommendationScores, lastViewedTime] = await Promise.all([
-      getValue<{ [contractId: string]: number }>(
-        userCacheCollection.doc('contractScores')
-      ),
-      getValue<{ [contractId: string]: number }>(
-        userCacheCollection.doc('lastViewTime')
-      ),
-    ]).then((dicts) => dicts.map((dict) => dict ?? {}))
 
-    const contracts = await contractsPromise
+    await batchedWaitAll(users.map((user) => () => updateFeed(user, contracts)))
-
-    const averageRecScore =
-      1 +
-      _.sumBy(
-        contracts.filter((c) => recommendationScores[c.id] !== undefined),
-        (c) => recommendationScores[c.id]
-      ) /
-        (contracts.length + 1)
-
-    console.log({ recommendationScores, averageRecScore, lastViewedTime })
-
-    const scoredContracts = contracts.map((contract) => {
-      const score = scoreContract(
-        contract,
-        recommendationScores[contract.id] ?? averageRecScore,
-        lastViewedTime[contract.id]
-      )
-      return [contract, score] as [Contract, number]
-    })
-
-    const sortedContracts = _.sortBy(
-      scoredContracts,
-      ([_, score]) => score
-    ).reverse()
-
-    console.log(sortedContracts.map(([c, score]) => c.question + ': ' + score))
-
-    const feedContracts = sortedContracts
-      .slice(0, MAX_FEED_CONTRACTS)
-      .map(([c]) => c)
-
-    const feed = await Promise.all(
-      feedContracts.map((contract) => getRecentBetsAndComments(contract))
-    )
-
-    console.log('feed', feed)
-
-    return { status: 'success', feed }
   })
 
+const updateFeed = async (user: User, contracts: Contract[]) => {
+  const userCacheCollection = firestore.collection(
+    `private-users/${user.id}/cache`
+  )
+  const [recommendationScores, lastViewedTime] = await Promise.all([
+    getValue<{ [contractId: string]: number }>(
+      userCacheCollection.doc('contractScores')
+    ),
+    getValue<{ [contractId: string]: number }>(
+      userCacheCollection.doc('lastViewTime')
+    ),
+  ]).then((dicts) => dicts.map((dict) => dict ?? {}))
+
+  const averageRecScore =
+    1 +
+    _.sumBy(
+      contracts.filter((c) => recommendationScores[c.id] !== undefined),
+      (c) => recommendationScores[c.id]
+    ) /
+      (contracts.length + 1)
+
+  const scoredContracts = contracts.map((contract) => {
+    const score = scoreContract(
+      contract,
+      recommendationScores[contract.id] ?? averageRecScore,
+      lastViewedTime[contract.id]
+    )
+    return [contract, score] as [Contract, number]
+  })
+
+  const sortedContracts = _.sortBy(
+    scoredContracts,
+    ([_, score]) => score
+  ).reverse()
+
+  console.log(sortedContracts.map(([c, score]) => c.question + ': ' + score))
+
+  const feedContracts = sortedContracts
+    .slice(0, MAX_FEED_CONTRACTS)
+    .map(([c]) => c)
+
+  const feed = await Promise.all(
+    feedContracts.map((contract) => getRecentBetsAndComments(contract))
+  )
+
+  await userCacheCollection.doc('feed').set(feed)
+}
+
 function scoreContract(
   contract: Contract,
   recommendationScore: number,
@@ -171,12 +170,16 @@ async function getRecentBetsAndComments(contract: Contract) {
       contractDoc
         .collection('bets')
         .where('createdTime', '>', Date.now() - DAY_MS)
+        .orderBy('createdTime', 'desc')
+        .limit(1)
     ),
 
     getValues<Comment>(
       contractDoc
         .collection('comments')
         .where('createdTime', '>', Date.now() - 3 * DAY_MS)
+        .orderBy('createdTime', 'desc')
+        .limit(3)
     ),
   ])
 

web/hooks/use-algo-feed.ts

@@ -5,9 +5,10 @@ import { Comment } from '../../common/comment'
 import { Contract } from '../../common/contract'
 import { useTimeSinceFirstRender } from './use-time-since-first-render'
 import { trackLatency } from '../lib/firebase/tracking'
-import { getFeed } from '../lib/firebase/api-call'
+import { User } from '../../common/user'
+import { getUserFeed } from '../lib/firebase/users'
 
-export const useAlgoFeed = () => {
+export const useAlgoFeed = (user: User | null | undefined) => {
   const [feed, setFeed] = useState<
     {
       contract: Contract
@@ -19,14 +20,15 @@ export const useAlgoFeed = () => {
   const getTime = useTimeSinceFirstRender()
 
   useEffect(() => {
-    getFeed().then(({ data }) => {
+    if (user) {
-      console.log('got data', data)
+      getUserFeed(user.id).then((feed) => {
-      setFeed(data.feed)
+        setFeed(feed)
 
-      trackLatency('feed', getTime())
+        trackLatency('feed', getTime())
-      console.log('feed load time', getTime())
+        console.log('feed load time', getTime())
-    })
+      })
-  }, [getTime])
+    }
+  }, [user, getTime])
 
   return feed
 }

web/lib/firebase/api-call.ts

@@ -1,7 +1,4 @@
 import { httpsCallable } from 'firebase/functions'
-import { Bet } from '../../../common/bet'
-import { Comment } from '../../../common/comment'
-import { Contract } from '../../../common/contract'
 import { Fold } from '../../../common/fold'
 import { User } from '../../../common/user'
 import { randomString } from '../../../common/util/random'
@@ -74,15 +71,3 @@ export const addLiquidity = (data: { amount: number; contractId: string }) => {
     .then((r) => r.data as { status: string })
     .catch((e) => ({ status: 'error', message: e.message }))
 }
-
-export const getFeed = cloudFunction<
-  undefined,
-  {
-    status: 'error' | 'success'
-    feed: {
-      contract: Contract
-      recentBets: Bet[]
-      recentComments: Comment[]
-    }[]
-  }
->('getFeed')

web/lib/firebase/users.ts

@@ -23,8 +23,11 @@ import _ from 'lodash'
 import { app } from './init'
 import { PrivateUser, User } from '../../../common/user'
 import { createUser } from './api-call'
-import { getValues, listenForValue, listenForValues } from './utils'
+import { getValue, getValues, listenForValue, listenForValues } from './utils'
 import { DAY_MS } from '../../../common/util/time'
+import { Contract } from './contracts'
+import { Bet } from './bets'
+import { Comment } from './comments'
 
 export type { User }
 
@@ -207,3 +210,15 @@ export async function getDailyNewUsers(
 
   return usersByDay
 }
+
+export async function getUserFeed(userId: string) {
+  const feedDoc = doc(db, 'private-users', userId, 'cache', 'feed')
+  const userFeed = await getValue<{
+    feed: {
+      contract: Contract
+      recentBets: Bet[]
+      recentComments: Comment[]
+    }[]
+  }>(feedDoc)
+  return userFeed?.feed ?? []
+}

web/pages/home.tsx

@@ -15,7 +15,7 @@ import { ContractPageContent } from './[username]/[contractSlug]'
 const Home = () => {
   const user = useUser()
 
-  const feed = useAlgoFeed()
+  const feed = useAlgoFeed(user)
 
   const router = useRouter()
   const { u: username, s: slug } = router.query