feat: add conversation caching

apps/web/src/components/utils/hooks/useMessagePreviews.tsx

@@ -12,11 +12,14 @@ import { useRouter } from 'next/router';
 import { useEffect, useState } from 'react';
 import { useAppStore } from 'src/store/app';
 import { useMessageStore } from 'src/store/message';
+import { useMessageCache } from 'src/store/message-cache';
+import { useAccount } from 'wagmi';
 
 const MAX_PROFILES_PER_REQUEST = 50;
 
 const useMessagePreviews = () => {
   const router = useRouter();
+  const { address: walletAddress } = useAccount();
   const currentProfile = useAppStore((state) => state.currentProfile);
   const conversations = useMessageStore((state) => state.conversations);
   const setConversations = useMessageStore((state) => state.setConversations);
@@ -38,6 +41,9 @@ const useMessagePreviews = () => {
   const [profilesToShow, setProfilesToShow] = useState<Map<string, Profile>>(new Map());
   const [requestedCount, setRequestedCount] = useState(0);
 
+  const setConversationCache = useMessageCache((state) => state.setConversations);
+  const addToConversationCache = useMessageCache((state) => state.addConversation);
+
   const getProfileFromKey = (key: string): string | null => {
     const parsed = parseConversationKey(key);
     const userProfileId = currentProfile?.id;
@@ -161,6 +167,12 @@ const useMessagePreviews = () => {
       if (newProfileIds.size > profileIds.size) {
         setProfileIds(newProfileIds);
       }
+
+      if (walletAddress) {
+        // Update the cache with the full conversation exports
+        const convoExports = await client.conversations.export();
+        setConversationCache(walletAddress, convoExports);
+      }
     };
 
     const closeConversationStream = async () => {
@@ -195,6 +207,11 @@ const useMessagePreviews = () => {
           setProfileIds(newProfileIds);
         }
         setConversations(newConversations);
+
+        if (walletAddress) {
+          // Add the newly streamed conversation to the cache
+          addToConversationCache(walletAddress, convo.export());
+        }
       }
     };
 

apps/web/src/components/utils/hooks/useXmtpClient.tsx

@@ -3,7 +3,8 @@ import { APP_NAME, APP_VERSION, LS_KEYS, XMTP_ENV } from 'data/constants';
 import { useCallback, useEffect, useState } from 'react';
 import { useAppStore } from 'src/store/app';
 import { useMessageStore } from 'src/store/message';
-import { useSigner } from 'wagmi';
+import { useMessageCache } from 'src/store/message-cache';
+import { useAccount, useSigner } from 'wagmi';
 
 const ENCODING = 'binary';
 
@@ -23,6 +24,9 @@ const storeKeys = (walletAddress: string, keys: Uint8Array) => {
   localStorage.setItem(buildLocalStorageKey(walletAddress), Buffer.from(keys).toString(ENCODING));
 };
 
+/**
+ * This will clear the conversation cache + the private keys
+ */
 const wipeKeys = (walletAddress: string) => {
   localStorage.removeItem(buildLocalStorageKey(walletAddress));
 };
@@ -33,6 +37,9 @@ const useXmtpClient = (cacheOnly = false) => {
   const setClient = useMessageStore((state) => state.setClient);
   const [awaitingXmtpAuth, setAwaitingXmtpAuth] = useState<boolean>();
   const { data: signer, isLoading } = useSigner();
+  const { address } = useAccount();
+
+  const conversationExports = useMessageCache((state) => state.conversations[address as `0x${string}`]);
 
   useEffect(() => {
     const initXmtpClient = async () => {
@@ -55,6 +62,10 @@ const useXmtpClient = (cacheOnly = false) => {
           appVersion: APP_NAME + '/' + APP_VERSION,
           privateKeyOverride: keys
         });
+        if (conversationExports && conversationExports.length) {
+          // Preload the client with conversations from the cache
+          await xmtp.conversations.import(conversationExports);
+        }
         setClient(xmtp);
         setAwaitingXmtpAuth(false);
       } else {

apps/web/src/store/message-cache.ts

@@ -0,0 +1,50 @@
+import type { ConversationExport } from '@xmtp/xmtp-js/dist/types/src/conversations/Conversation';
+import { create } from 'zustand';
+import { persist } from 'zustand/middleware';
+
+// If any breaking changes to the ConversationExport schema occur, increment the cache version.
+const CONVERSATION_CACHE_VERSION = 1;
+
+/**
+ * The MessageCache is a JSON serializable Zustand store that is persisted to LocalStorage
+ * Persisting conversations to the cache saves on both bandwidth and CPU cycles, as we don't have to re-fetch or re-decrypt conversations on subsequent page loads
+ */
+interface MessageCache {
+  // Mapping of conversation exports, keyed by wallet address
+  conversations: { [walletAddress: string]: ConversationExport[] };
+  // Overwrite the cache for a given wallet address
+  setConversations: (walletAddress: string, conversations: ConversationExport[]) => void;
+  // Add a single conversation to the cache.
+  // Deduping only happens at the time the cache is loaded, so be careful to not overfill or you will use more LocalStorage space than necessary
+  addConversation: (walletAddress: string, conversation: ConversationExport) => void;
+}
+
+export const useMessageCache = create<MessageCache>()(
+  persist(
+    (set, get) => ({
+      conversations: {},
+      setConversations: (walletAddress: string, convos: ConversationExport[]) =>
+        set({
+          conversations: { ...get().conversations, [walletAddress]: convos }
+        }),
+      addConversation: (walletAddress: string, convo: ConversationExport) => {
+        const existing = get().conversations;
+        const existingForWallet = existing[walletAddress] || [];
+        return set({
+          conversations: {
+            ...existing,
+            [walletAddress]: [...existingForWallet, convo]
+          }
+        });
+      }
+    }),
+    {
+      // Ensure that the LocalStorage key includes the network and the cache version
+      // If any breaking changes to the ConversationExport schema occur, increment the cache version.
+      name: `lenster:conversations:${
+        process.env.NEXT_PUBLIC_LENS_NETWORK || 'unknown'
+      }:v${CONVERSATION_CACHE_VERSION}`,
+      partialize: (state) => ({ conversations: state.conversations })
+    }
+  )
+);