perf: cache link previews

Changelog-Added: Cache link previews

damus.xcodeproj/project.pbxproj

@@ -51,6 +51,7 @@
 		4C363AA428296DEE006E126D /* SearchModel.swift in Sources */ = {isa = PBXBuildFile; fileRef = 4C363AA328296DEE006E126D /* SearchModel.swift */; };
 		4C363AA828297703006E126D /* InsertSort.swift in Sources */ = {isa = PBXBuildFile; fileRef = 4C363AA728297703006E126D /* InsertSort.swift */; };
 		4C3A1D332960DB0500558C0F /* Markdown.swift in Sources */ = {isa = PBXBuildFile; fileRef = 4C3A1D322960DB0500558C0F /* Markdown.swift */; };
+		4C3A1D3729637E0500558C0F /* PreviewCache.swift in Sources */ = {isa = PBXBuildFile; fileRef = 4C3A1D3629637E0500558C0F /* PreviewCache.swift */; };
 		4C3AC79B28306D7B00E1F516 /* Contacts.swift in Sources */ = {isa = PBXBuildFile; fileRef = 4C3AC79A28306D7B00E1F516 /* Contacts.swift */; };
 		4C3AC79D2833036D00E1F516 /* FollowingView.swift in Sources */ = {isa = PBXBuildFile; fileRef = 4C3AC79C2833036D00E1F516 /* FollowingView.swift */; };
 		4C3AC79F2833115300E1F516 /* FollowButtonView.swift in Sources */ = {isa = PBXBuildFile; fileRef = 4C3AC79E2833115300E1F516 /* FollowButtonView.swift */; };
@@ -207,6 +208,7 @@
 		4C363AA328296DEE006E126D /* SearchModel.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = SearchModel.swift; sourceTree = "<group>"; };
 		4C363AA728297703006E126D /* InsertSort.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = InsertSort.swift; sourceTree = "<group>"; };
 		4C3A1D322960DB0500558C0F /* Markdown.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = Markdown.swift; sourceTree = "<group>"; };
+		4C3A1D3629637E0500558C0F /* PreviewCache.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = PreviewCache.swift; sourceTree = "<group>"; };
 		4C3AC79A28306D7B00E1F516 /* Contacts.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = Contacts.swift; sourceTree = "<group>"; };
 		4C3AC79C2833036D00E1F516 /* FollowingView.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = FollowingView.swift; sourceTree = "<group>"; };
 		4C3AC79E2833115300E1F516 /* FollowButtonView.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = FollowButtonView.swift; sourceTree = "<group>"; };
@@ -542,6 +544,7 @@
 				4C216F352870A9A700040376 /* InputDismissKeyboard.swift */,
 				3169CAEC294FCCFC00EE4006 /* Constants.swift */,
 				3165648A295B70D500C64604 /* LinkView.swift */,
+				4C3A1D3629637E0500558C0F /* PreviewCache.swift */,
 			);
 			path = Util;
 			sourceTree = "<group>";
@@ -842,6 +845,7 @@
 				3169CAE6294E69C000EE4006 /* EmptyTimelineView.swift in Sources */,
 				4C3EA64928FF597700C48A62 /* bech32.c in Sources */,
 				4C90BD162839DB54008EE7EF /* NostrMetadata.swift in Sources */,
+				4C3A1D3729637E0500558C0F /* PreviewCache.swift in Sources */,
 				4C3EA67528FF7A5A00C48A62 /* take.c in Sources */,
 				4C3AC7A12835A81400E1F516 /* SetupView.swift in Sources */,
 				4C06670128FC7C5900038D2A /* RelayView.swift in Sources */,

damus/ContentView.swift

@@ -423,7 +423,8 @@ struct ContentView: View {
                                 contacts: Contacts(),
                                 tips: TipCounter(our_pubkey: pubkey),
                                 profiles: Profiles(),
-                                dms: home.dms
+                                dms: home.dms,
+                                previews: PreviewCache()
         )
         home.damus_state = self.damus_state!
         

damus/Models/DamusState.swift

@@ -6,6 +6,7 @@
 //
 
 import Foundation
+import LinkPresentation
 
 struct DamusState {
     let pool: RelayPool
@@ -16,12 +17,13 @@ struct DamusState {
     let tips: TipCounter
     let profiles: Profiles
     let dms: DirectMessagesModel
+    let previews: PreviewCache
     
     var pubkey: String {
         return keypair.pubkey
     }
     
     static var empty: DamusState {
-        return DamusState.init(pool: RelayPool(), keypair: Keypair(pubkey: "", privkey: ""), likes: EventCounter(our_pubkey: ""), boosts: EventCounter(our_pubkey: ""), contacts: Contacts(), tips: TipCounter(our_pubkey: ""), profiles: Profiles(), dms: DirectMessagesModel())
+        return DamusState.init(pool: RelayPool(), keypair: Keypair(pubkey: "", privkey: ""), likes: EventCounter(our_pubkey: ""), boosts: EventCounter(our_pubkey: ""), contacts: Contacts(), tips: TipCounter(our_pubkey: ""), profiles: Profiles(), dms: DirectMessagesModel(), previews: PreviewCache())
     }
 }

damus/Util/Constants.swift

@@ -11,7 +11,7 @@ public class Constants {
     
     static let PUB_KEY = "3efdaebb1d8923ebd99c9e7ace3b4194ab45512e2be79c1b7d68d9243e0d2681"
     
-    static let EXAMPLE_DEMOS = DamusState(pool: RelayPool(), keypair: Keypair(pubkey: PUB_KEY, privkey: "privkey"), likes: EventCounter(our_pubkey: PUB_KEY), boosts: EventCounter(our_pubkey: PUB_KEY), contacts: Contacts(), tips: TipCounter(our_pubkey: PUB_KEY), profiles: Profiles(), dms: DirectMessagesModel())
+    static let EXAMPLE_DEMOS: DamusState = .empty
     
     static let EXAMPLE_EVENTS = [
         NostrEvent(id: UUID().description, content: "Nostr - Damus... Haha get it? Bonjour Le Monde mon Ami! C'est la tres importante", pubkey: "3efdaebb1d8923ebd99c9e7ace3b4194ab45512e2be79c1b7d68d9243e0d2681"),

damus/Views/ChatView.swift

@@ -96,7 +96,7 @@ struct ChatView: View {
                 
                     if let ref_id = thread.replies.lookup(event.id) {
                         if !is_reply_to_prev() {
-                            ReplyQuoteView(privkey: damus_state.keypair.privkey, quoter: event, event_id: ref_id, profiles: damus_state.profiles)
+                            ReplyQuoteView(privkey: damus_state.keypair.privkey, quoter: event, event_id: ref_id, profiles: damus_state.profiles, previews: damus_state.previews)
                                 .frame(maxHeight: expand_reply ? nil : 100)
                                 .environmentObject(thread)
                                 .onTapGesture {
@@ -106,7 +106,7 @@ struct ChatView: View {
                         }
                     }
                     
-                    NoteContentView(privkey: damus_state.keypair.privkey, event: event, profiles: damus_state.profiles, show_images: should_show_images(contacts: damus_state.contacts, ev: event, our_pubkey: damus_state.pubkey), artifacts: .just_content(event.content), size: .normal)
+                    NoteContentView(privkey: damus_state.keypair.privkey, event: event, profiles: damus_state.profiles, previews: damus_state.previews, show_images: should_show_images(contacts: damus_state.contacts, ev: event, our_pubkey: damus_state.pubkey), artifacts: .just_content(event.content), size: .normal)
 
                     if is_active || next_ev == nil || next_ev!.pubkey != event.pubkey {
                         let bar = make_actionbar_model(ev: event, damus: damus_state)

damus/Views/DMView.swift

@@ -23,7 +23,7 @@ struct DMView: View {
             
             let should_show_img = should_show_images(contacts: damus_state.contacts, ev: event, our_pubkey: damus_state.pubkey)
             
-            NoteContentView(privkey: damus_state.keypair.privkey, event: event, profiles: damus_state.profiles, show_images: should_show_img, artifacts: .just_content(event.get_content(damus_state.keypair.privkey)), size: .normal)
+            NoteContentView(privkey: damus_state.keypair.privkey, event: event, profiles: damus_state.profiles, previews: damus_state.previews, show_images: should_show_img, artifacts: .just_content(event.get_content(damus_state.keypair.privkey)), size: .normal)
                 .foregroundColor(is_ours ? Color.white : Color.primary)
                 .padding(10)
                 .background(is_ours ? Color.accentColor : Color.secondary.opacity(0.15))

damus/Views/EventView.swift

@@ -249,7 +249,7 @@ struct EventView: View {
 
                 let should_show_img = should_show_images(contacts: damus.contacts, ev: event, our_pubkey: damus.pubkey)
                 
-                NoteContentView(privkey: damus.keypair.privkey, event: event, profiles: damus.profiles, show_images: should_show_img, artifacts: .just_content(content), size: self.size)
+                NoteContentView(privkey: damus.keypair.privkey, event: event, profiles: damus.profiles, previews: damus.previews, show_images: should_show_img, artifacts: .just_content(content), size: self.size)
                     .frame(maxWidth: .infinity, alignment: .leading)
                     .allowsHitTesting(!embedded)
                 

damus/Views/NoteContentView.swift

@@ -61,12 +61,13 @@ struct NoteContentView: View {
     let privkey: String?
     let event: NostrEvent
     let profiles: Profiles
+    let previews: PreviewCache
     
     let show_images: Bool
     
     @State var artifacts: NoteArtifacts
     
-    @State var metaData: LPLinkMetadata? = nil
+    @State var preview: LinkViewRepresentable? = nil
     let size: EventViewKind
     
     func MainContent() -> some View {
@@ -89,8 +90,8 @@ struct NoteContentView: View {
                 InvoicesView(invoices: artifacts.invoices)
             }
             
-            if show_images, self.metaData != nil {
+            if show_images, self.preview != nil {
-                LinkViewRepresentable(metadata: self.metaData)
+                self.preview
             } else {
                 ForEach(artifacts.links, id:\.self) { link in
                     LinkViewRepresentable(url: link)
@@ -123,9 +124,22 @@ struct NoteContentView: View {
                 }
             }
             .task {
+                if let preview = previews.lookup(self.event.id) {
+                    switch preview {
+                    case .value(let view):
+                        self.preview = view
+                    case .failed:
+                        // don't try to refetch meta if we've failed
+                        return
+                    }
+                }
+                
                 if show_images, artifacts.links.count == 1 {
+                    let meta = await getMetaData(for: artifacts.links.first!)
                     
-                    self.metaData = await getMetaData(for: artifacts.links.first!)
+                    let view = LinkViewRepresentable(metadata: meta)
+                    previews.store(evid: self.event.id, preview: view)
+                    self.preview = view
                 }
             }
     }
@@ -170,6 +184,6 @@ struct NoteContentView_Previews: PreviewProvider {
         let state = test_damus_state()
         let content = "hi there https://jb55.com/s/Oct12-150217.png 5739a762ef6124dd.jpg"
         let artifacts = NoteArtifacts(content: content, images: [], invoices: [], links: [])
-        NoteContentView(privkey: "", event: NostrEvent(content: content, pubkey: "pk"), profiles: state.profiles, show_images: true, artifacts: artifacts, size: .normal)
+        NoteContentView(privkey: "", event: NostrEvent(content: content, pubkey: "pk"), profiles: state.profiles, previews: PreviewCache(), show_images: true, artifacts: artifacts, size: .normal)
     }
 }

damus/Views/ProfileView.swift

@@ -306,8 +306,7 @@ struct ProfileView_Previews: PreviewProvider {
 
 func test_damus_state() -> DamusState {
     let pubkey = "3efdaebb1d8923ebd99c9e7ace3b4194ab45512e2be79c1b7d68d9243e0d2681"
-    let damus = DamusState(pool: RelayPool(), keypair: Keypair(pubkey: pubkey, privkey: "privkey"), likes: EventCounter(our_pubkey: pubkey), boosts: EventCounter(our_pubkey: pubkey), contacts: Contacts(), tips: TipCounter(our_pubkey: pubkey), profiles: Profiles(), dms: DirectMessagesModel())
+    let damus: DamusState = .empty
-    
     let prof = Profile(name: "damus", display_name: "Damus", about: "iOS app!", picture: "https://damus.io/img/logo.png", website: "https://damus.io", lud06: nil, lud16: "jb55@sendsats.lol", nip05: "damus.io")
     let tsprof = TimestampedProfile(profile: prof, timestamp: 0)
     damus.profiles.add(id: pubkey, profile: tsprof)

damus/Views/ReplyQuoteView.swift

@@ -12,6 +12,7 @@ struct ReplyQuoteView: View {
     let quoter: NostrEvent
     let event_id: String
     let profiles: Profiles
+    let previews: PreviewCache
     
     @EnvironmentObject var thread: ThreadModel
     
@@ -31,7 +32,7 @@ struct ReplyQuoteView: View {
                         .foregroundColor(.gray)
                 }
                 
-                NoteContentView(privkey: privkey, event: event, profiles: profiles, show_images: false, artifacts: .just_content(event.content), size: .normal)
+                NoteContentView(privkey: privkey, event: event, profiles: profiles, previews: previews, show_images: false, artifacts: .just_content(event.content), size: .normal)
                     .font(.callout)
                     .foregroundColor(.accentColor)
                 
@@ -58,7 +59,7 @@ struct ReplyQuoteView_Previews: PreviewProvider {
     static var previews: some View {
         let s = test_damus_state()
         let quoter = NostrEvent(content: "a\nb\nc", pubkey: "pubkey")
-        ReplyQuoteView(privkey: s.keypair.privkey, quoter: quoter, event_id: "pubkey2", profiles: s.profiles)
+        ReplyQuoteView(privkey: s.keypair.privkey, quoter: quoter, event_id: "pubkey2", profiles: s.profiles, previews: PreviewCache())
             .environmentObject(ThreadModel(event: quoter, damus_state: s))
     }
 }

damus/damusApp.swift

@@ -7,6 +7,7 @@
 
 import SwiftUI
 
+
 @main
 struct damusApp: App {
     var body: some Scene {