Make a React context to be the source of truth for authenticated user (#675)

* Make a React context to manage the logged in user events

* Remove unnecessary new user creation promise machinery

* Slight refactoring to auth context code

* Improvements in response to James feedback

web/components/auth-context.tsx

@@ -0,0 +1,77 @@
+import { createContext, useEffect } from 'react'
+import { User } from 'common/user'
+import { onIdTokenChanged } from 'firebase/auth'
+import {
+  auth,
+  listenForUser,
+  getUser,
+  setCachedReferralInfoForUser,
+} from 'web/lib/firebase/users'
+import { deleteAuthCookies, setAuthCookies } from 'web/lib/firebase/auth'
+import { createUser } from 'web/lib/firebase/api'
+import { randomString } from 'common/util/random'
+import { identifyUser, setUserProperty } from 'web/lib/service/analytics'
+import { useStateCheckEquality } from 'web/hooks/use-state-check-equality'
+
+// Either we haven't looked up the logged in user yet (undefined), or we know
+// the user is not logged in (null), or we know the user is logged in (User).
+type AuthUser = undefined | null | User
+
+const CACHED_USER_KEY = 'CACHED_USER_KEY'
+
+const ensureDeviceToken = () => {
+  let deviceToken = localStorage.getItem('device-token')
+  if (!deviceToken) {
+    deviceToken = randomString()
+    localStorage.setItem('device-token', deviceToken)
+  }
+  return deviceToken
+}
+
+export const AuthContext = createContext<AuthUser>(null)
+
+export function AuthProvider({ children }: any) {
+  const [authUser, setAuthUser] = useStateCheckEquality<AuthUser>(undefined)
+
+  useEffect(() => {
+    const cachedUser = localStorage.getItem(CACHED_USER_KEY)
+    setAuthUser(cachedUser && JSON.parse(cachedUser))
+  }, [setAuthUser])
+
+  useEffect(() => {
+    return onIdTokenChanged(auth, async (fbUser) => {
+      if (fbUser) {
+        let user = await getUser(fbUser.uid)
+        if (!user) {
+          const deviceToken = ensureDeviceToken()
+          user = (await createUser({ deviceToken })) as User
+        }
+        setAuthUser(user)
+        // Persist to local storage, to reduce login blink next time.
+        // Note: Cap on localStorage size is ~5mb
+        localStorage.setItem(CACHED_USER_KEY, JSON.stringify(user))
+        setCachedReferralInfoForUser(user)
+        setAuthCookies(await fbUser.getIdToken(), fbUser.refreshToken)
+      } else {
+        // User logged out; reset to null
+        setAuthUser(null)
+        localStorage.removeItem(CACHED_USER_KEY)
+        deleteAuthCookies()
+      }
+    })
+  }, [setAuthUser])
+
+  const authUserId = authUser?.id
+  const authUsername = authUser?.username
+  useEffect(() => {
+    if (authUserId && authUsername) {
+      identifyUser(authUserId)
+      setUserProperty('username', authUsername)
+      return listenForUser(authUserId, setAuthUser)
+    }
+  }, [authUserId, authUsername, setAuthUser])
+
+  return (
+    <AuthContext.Provider value={authUser}>{children}</AuthContext.Provider>
+  )
+}

web/components/bets-list.tsx

@@ -78,10 +78,10 @@ export function BetsList(props: {
 
   const getTime = useTimeSinceFirstRender()
   useEffect(() => {
-    if (bets && contractsById) {
-      trackLatency('portfolio', getTime())
+    if (bets && contractsById && signedInUser) {
+      trackLatency(signedInUser.id, 'portfolio', getTime())
     }
-  }, [bets, contractsById, getTime])
+  }, [signedInUser, bets, contractsById, getTime])
 
   if (!bets || !contractsById) {
     return <LoadingIndicator />

web/components/feed/feed-items.tsx

@@ -23,6 +23,7 @@ import BetRow from '../bet-row'
 import { Avatar } from '../avatar'
 import { ActivityItem } from './activity-items'
 import { useSaveSeenContract } from 'web/hooks/use-seen-contracts'
+import { useUser } from 'web/hooks/use-user'
 import { trackClick } from 'web/lib/firebase/tracking'
 import { DAY_MS } from 'common/util/time'
 import NewContractBadge from '../new-contract-badge'
@@ -118,6 +119,7 @@ export function FeedQuestion(props: {
   const { volumeLabel } = contractMetrics(contract)
   const isBinary = outcomeType === 'BINARY'
   const isNew = createdTime > Date.now() - DAY_MS && !isResolved
+  const user = useUser()
 
   return (
     <div className={'flex gap-2'}>
@@ -149,7 +151,7 @@ export function FeedQuestion(props: {
             href={
               props.contractPath ? props.contractPath : contractPath(contract)
             }
-            onClick={() => trackClick(contract.id)}
+            onClick={() => user && trackClick(user.id, contract.id)}
             className="text-lg text-indigo-700 sm:text-xl"
           >
             {question}

web/hooks/use-algo-feed.ts

@@ -25,7 +25,7 @@ export const useAlgoFeed = (
           getDefaultFeed().then((feed) => setAllFeed(feed))
         } else setAllFeed(feed)
 
-        trackLatency('feed', getTime())
+        trackLatency(user.id, 'feed', getTime())
         console.log('"all" feed load time', getTime())
       })
 

web/hooks/use-seen-contracts.ts

@@ -3,6 +3,7 @@ import { useEffect, useState } from 'react'
 import { Contract } from 'common/contract'
 import { trackView } from 'web/lib/firebase/tracking'
 import { useIsVisible } from './use-is-visible'
+import { useUser } from './use-user'
 
 export const useSeenContracts = () => {
   const [seenContracts, setSeenContracts] = useState<{
@@ -21,18 +22,19 @@ export const useSaveSeenContract = (
   contract: Contract
 ) => {
   const isVisible = useIsVisible(elem)
+  const user = useUser()
 
   useEffect(() => {
-    if (isVisible) {
+    if (isVisible && user) {
       const newSeenContracts = {
         ...getSeenContracts(),
         [contract.id]: Date.now(),
       }
       localStorage.setItem(key, JSON.stringify(newSeenContracts))
 
-      trackView(contract.id)
+      trackView(user.id, contract.id)
     }
-  }, [isVisible, contract])
+  }, [isVisible, user, contract])
 }
 
 const key = 'feed-seen-contracts'

web/hooks/use-user.ts

@@ -1,4 +1,4 @@
-import { useEffect, useState } from 'react'
+import { useContext, useEffect, useState } from 'react'
 import { useFirestoreDocumentData } from '@react-query-firebase/firestore'
 import { QueryClient } from 'react-query'
 
@@ -6,32 +6,14 @@ import { doc, DocumentData } from 'firebase/firestore'
 import { PrivateUser } from 'common/user'
 import {
   getUser,
-  listenForLogin,
   listenForPrivateUser,
-  listenForUser,
   User,
   users,
 } from 'web/lib/firebase/users'
-import { useStateCheckEquality } from './use-state-check-equality'
-import { identifyUser, setUserProperty } from 'web/lib/service/analytics'
+import { AuthContext } from 'web/components/auth-context'
 
 export const useUser = () => {
-  const [user, setUser] = useStateCheckEquality<User | null | undefined>(
-    undefined
-  )
-
-  useEffect(() => listenForLogin(setUser), [setUser])
-
-  useEffect(() => {
-    if (user) {
-      identifyUser(user.id)
-      setUserProperty('username', user.username)
-
-      return listenForUser(user.id, setUser)
-    }
-  }, [user, setUser])
-
-  return user
+  return useContext(AuthContext)
 }
 
 export const usePrivateUser = (userId?: string) => {

web/lib/firebase/tracking.ts

@@ -2,16 +2,9 @@ import { doc, collection, setDoc } from 'firebase/firestore'
 
 import { db } from './init'
 import { ClickEvent, LatencyEvent, View } from 'common/tracking'
-import { listenForLogin, User } from './users'
 
-let user: User | null = null
-if (typeof window !== 'undefined') {
-  listenForLogin((u) => (user = u))
-}
-
-export async function trackView(contractId: string) {
-  if (!user) return
-  const ref = doc(collection(db, 'private-users', user.id, 'views'))
+export async function trackView(userId: string, contractId: string) {
+  const ref = doc(collection(db, 'private-users', userId, 'views'))
 
   const view: View = {
     contractId,
@@ -21,9 +14,8 @@ export async function trackView(contractId: string) {
   return await setDoc(ref, view)
 }
 
-export async function trackClick(contractId: string) {
-  if (!user) return
-  const ref = doc(collection(db, 'private-users', user.id, 'events'))
+export async function trackClick(userId: string, contractId: string) {
+  const ref = doc(collection(db, 'private-users', userId, 'events'))
 
   const clickEvent: ClickEvent = {
     type: 'click',
@@ -35,11 +27,11 @@ export async function trackClick(contractId: string) {
 }
 
 export async function trackLatency(
+  userId: string,
   type: 'feed' | 'portfolio',
   latency: number
 ) {
-  if (!user) return
-  const ref = doc(collection(db, 'private-users', user.id, 'latency'))
+  const ref = doc(collection(db, 'private-users', userId, 'latency'))
 
   const latencyEvent: LatencyEvent = {
     type,

web/lib/firebase/users.ts

@@ -15,15 +15,10 @@ import {
 } from 'firebase/firestore'
 import { getAuth } from 'firebase/auth'
 import { ref, getStorage, uploadBytes, getDownloadURL } from 'firebase/storage'
-import {
-  onIdTokenChanged,
-  GoogleAuthProvider,
-  signInWithPopup,
-} from 'firebase/auth'
+import { GoogleAuthProvider, signInWithPopup } from 'firebase/auth'
 import { zip } from 'lodash'
 import { app, db } from './init'
 import { PortfolioMetrics, PrivateUser, User } from 'common/user'
-import { createUser } from './api'
 import {
   coll,
   getValue,
@@ -37,13 +32,11 @@ import { safeLocalStorage } from '../util/local'
 import { filterDefined } from 'common/util/array'
 import { addUserToGroupViaId } from 'web/lib/firebase/groups'
 import { removeUndefinedProps } from 'common/util/object'
-import { randomString } from 'common/util/random'
 import dayjs from 'dayjs'
 import utc from 'dayjs/plugin/utc'
 dayjs.extend(utc)
 
 import { track } from '@amplitude/analytics-browser'
-import { deleteAuthCookies, setAuthCookies } from './auth'
 
 export const users = coll<User>('users')
 export const privateUsers = coll<PrivateUser>('private-users')
@@ -97,7 +90,6 @@ export function listenForPrivateUser(
   return listenForValue<PrivateUser>(userRef, setPrivateUser)
 }
 
-const CACHED_USER_KEY = 'CACHED_USER_KEY'
 const CACHED_REFERRAL_USERNAME_KEY = 'CACHED_REFERRAL_KEY'
 const CACHED_REFERRAL_CONTRACT_ID_KEY = 'CACHED_REFERRAL_CONTRACT_KEY'
 const CACHED_REFERRAL_GROUP_ID_KEY = 'CACHED_REFERRAL_GROUP_KEY'
@@ -130,7 +122,7 @@ export function writeReferralInfo(
     local?.setItem(CACHED_REFERRAL_CONTRACT_ID_KEY, contractId)
 }
 
-async function setCachedReferralInfoForUser(user: User | null) {
+export async function setCachedReferralInfoForUser(user: User | null) {
   if (!user || user.referredByUserId) return
   // if the user wasn't created in the last minute, don't bother
   const now = dayjs().utc()
@@ -181,46 +173,6 @@ async function setCachedReferralInfoForUser(user: User | null) {
   local?.removeItem(CACHED_REFERRAL_CONTRACT_ID_KEY)
 }
 
-// used to avoid weird race condition
-let createUserPromise: Promise<User> | undefined = undefined
-
-export function listenForLogin(onUser: (user: User | null) => void) {
-  const local = safeLocalStorage()
-  const cachedUser = local?.getItem(CACHED_USER_KEY)
-  onUser(cachedUser && JSON.parse(cachedUser))
-
-  return onIdTokenChanged(auth, async (fbUser) => {
-    if (fbUser) {
-      let user: User | null = await getUser(fbUser.uid)
-      if (!user) {
-        if (createUserPromise == null) {
-          const local = safeLocalStorage()
-          let deviceToken = local?.getItem('device-token')
-          if (!deviceToken) {
-            deviceToken = randomString()
-            local?.setItem('device-token', deviceToken)
-          }
-          createUserPromise = createUser({ deviceToken }).then((r) => r as User)
-        }
-        user = await createUserPromise
-      }
-      onUser(user)
-
-      // Persist to local storage, to reduce login blink next time.
-      // Note: Cap on localStorage size is ~5mb
-      local?.setItem(CACHED_USER_KEY, JSON.stringify(user))
-      setCachedReferralInfoForUser(user)
-      setAuthCookies(await fbUser.getIdToken(), fbUser.refreshToken)
-    } else {
-      // User logged out; reset to null
-      onUser(null)
-      createUserPromise = undefined
-      local?.removeItem(CACHED_USER_KEY)
-      deleteAuthCookies()
-    }
-  })
-}
-
 export async function firebaseLogin() {
   const provider = new GoogleAuthProvider()
   return signInWithPopup(auth, provider)

web/pages/_app.tsx

@@ -5,6 +5,7 @@ import Head from 'next/head'
 import Script from 'next/script'
 import { usePreserveScroll } from 'web/hooks/use-preserve-scroll'
 import { QueryClient, QueryClientProvider } from 'react-query'
+import { AuthProvider } from 'web/components/auth-context'
 
 function firstLine(msg: string) {
   return msg.replace(/\r?\n.*/s, '')
@@ -78,9 +79,11 @@ function MyApp({ Component, pageProps }: AppProps) {
         />
       </Head>
 
-      <QueryClientProvider client={queryClient}>
-        <Component {...pageProps} />
-      </QueryClientProvider>
+      <AuthProvider>
+        <QueryClientProvider client={queryClient}>
+          <Component {...pageProps} />
+        </QueryClientProvider>
+      </AuthProvider>
     </>
   )
 }