String trimming in a centralized manner (#1079)

* String trimming in a centralized manner

* Fix empty-nickname case

bitchat/Models/BitchatMessage+Media.swift

@@ -42,9 +42,11 @@ extension BitchatMessage {
         guard let baseDirectory = Cache.shared.filesDir else { return nil }
 
         func url(for category: MimeType.Category) -> URL? {
-            guard content.hasPrefix(category.messagePrefix) else { return nil }
-            let filename = String(content.dropFirst(category.messagePrefix.count)).trimmingCharacters(in: .whitespacesAndNewlines)
-            guard !filename.isEmpty else { return nil }
+            guard content.hasPrefix(category.messagePrefix),
+                  let filename = String(content.dropFirst(category.messagePrefix.count)).trimmedOrNilIfEmpty
+            else {
+                return nil
+            }
 
             // Check outgoing first for sent messages, incoming for received
             let subdir = sender == nickname ? "\(category.mediaDir)/outgoing" : "\(category.mediaDir)/incoming"

bitchat/Models/BitchatMessage.swift

@@ -338,7 +338,7 @@ extension BitchatMessage {
 extension Array where Element == BitchatMessage {
     /// Filters out empty ones and deduplicate by ID while preserving order (from oldest to newest)
     func cleanedAndDeduped() -> [Element] {
-        let arr = filter { $0.content.trimmingCharacters(in: .whitespacesAndNewlines).isEmpty == false }
+        let arr = filter { $0.content.trimmed.isEmpty == false }
         guard arr.count > 1 else {
             return arr
         }

bitchat/Nostr/GeoRelayDirectory.swift

@@ -377,10 +377,9 @@ final class GeoRelayDirectory {
         var result: Set<Entry> = []
         let lines = text.split(whereSeparator: { $0.isNewline })
         for (idx, raw) in lines.enumerated() {
-            let line = raw.trimmingCharacters(in: .whitespacesAndNewlines)
-            if line.isEmpty { continue }
+            guard let line = raw.trimmedOrNilIfEmpty else { continue }
             if idx == 0 && line.lowercased().contains("relay url") { continue }
-            let parts = line.split(separator: ",").map { String($0).trimmingCharacters(in: .whitespaces) }
+            let parts = line.split(separator: ",").map { $0.trimmed }
             guard parts.count >= 3 else { continue }
             var host = parts[0]
             host = host.replacingOccurrences(of: "https://", with: "")

bitchat/Nostr/NostrProtocol.swift

@@ -109,7 +109,7 @@ struct NostrProtocol {
         teleported: Bool = false
     ) throws -> NostrEvent {
         var tags = [["g", geohash]]
-        if let nickname = nickname?.trimmingCharacters(in: .whitespacesAndNewlines), !nickname.isEmpty {
+        if let nickname = nickname?.trimmedOrNilIfEmpty {
             tags.append(["n", nickname])
         }
         if teleported {
@@ -152,7 +152,7 @@ struct NostrProtocol {
         nickname: String? = nil
     ) throws -> NostrEvent {
         var tags = [["g", geohash]]
-        if let nickname = nickname?.trimmingCharacters(in: .whitespacesAndNewlines), !nickname.isEmpty {
+        if let nickname = nickname?.trimmedOrNilIfEmpty {
             tags.append(["n", nickname])
         }
         let event = NostrEvent(

bitchat/Protocols/BinaryEncodingUtils.swift

@@ -28,7 +28,7 @@ extension Data {
     ///   Whitespace is trimmed. Must have even length after prefix removal.
     /// - Returns: nil if the string has odd length or contains invalid hex characters.
     init?(hexString: String) {
-        var hex = hexString.trimmingCharacters(in: .whitespaces)
+        var hex = hexString.trimmed
 
         // Remove optional 0x prefix
         if hex.hasPrefix("0x") || hex.hasPrefix("0X") {

bitchat/Services/BLE/BLEService.swift

@@ -1354,7 +1354,7 @@ final class BLEService: NSObject {
         let invalid = CharacterSet(charactersIn: "<>:\"|?*\0").union(.controlCharacters)
         candidate = candidate.components(separatedBy: invalid).joined(separator: "_")
 
-        candidate = candidate.trimmingCharacters(in: .whitespacesAndNewlines)
+        candidate = candidate.trimmed
         if candidate.isEmpty { candidate = defaultName }
 
         // Security: Reject dotfiles (hidden file attacks)

bitchat/Services/CommandProcessor.swift

@@ -166,7 +166,7 @@ final class CommandProcessor {
     }
     
     private func handleEmote(_ args: String, command: String, action: String, emoji: String, suffix: String = "") -> CommandResult {
-        let targetName = args.trimmingCharacters(in: .whitespaces)
+        let targetName = args.trimmed
         guard !targetName.isEmpty else {
             return .error(message: "usage: /\(command) <nickname>")
         }
@@ -209,7 +209,7 @@ final class CommandProcessor {
     }
     
     private func handleBlock(_ args: String) -> CommandResult {
-        let targetName = args.trimmingCharacters(in: .whitespaces)
+        let targetName = args.trimmed
         
         if targetName.isEmpty {
             // List blocked users (mesh) and geohash (Nostr) blocks
@@ -284,7 +284,7 @@ final class CommandProcessor {
     }
     
     private func handleUnblock(_ args: String) -> CommandResult {
-        let targetName = args.trimmingCharacters(in: .whitespaces)
+        let targetName = args.trimmed
         guard !targetName.isEmpty else {
             return .error(message: "usage: /unblock <nickname>")
         }
@@ -311,7 +311,7 @@ final class CommandProcessor {
     }
     
     private func handleFavorite(_ args: String, add: Bool) -> CommandResult {
-        let targetName = args.trimmingCharacters(in: .whitespaces)
+        let targetName = args.trimmed
         guard !targetName.isEmpty else {
             return .error(message: "usage: /\(add ? "fav" : "unfav") <nickname>")
         }

bitchat/Services/LocationNotesManager.swift

@@ -63,7 +63,7 @@ final class LocationNotesManager: ObservableObject {
 
         var displayName: String {
             let suffix = String(pubkey.suffix(4))
-            if let nick = nickname, !nick.trimmingCharacters(in: .whitespacesAndNewlines).isEmpty {
+            if let nick = nickname?.trimmedOrNilIfEmpty {
                 return "\(nick)#\(suffix)"
             }
             return "anon#\(suffix)"
@@ -199,8 +199,7 @@ final class LocationNotesManager: ObservableObject {
 
     /// Send a location note for the current geohash using the per-geohash identity.
     func send(content: String, nickname: String) {
-        let trimmed = content.trimmingCharacters(in: .whitespacesAndNewlines)
-        guard !trimmed.isEmpty else { return }
+        guard let trimmed = content.trimmedOrNilIfEmpty else { return }
         let relays = dependencies.relayLookup(geohash, TransportConfig.nostrGeoRelayCount)
         guard !relays.isEmpty else {
             state = .noRelays

bitchat/Services/LocationStateManager.swift

@@ -597,7 +597,7 @@ final class LocationStateManager: NSObject, CLLocationManagerDelegate, Observabl
     private static func normalizeGeohash(_ s: String) -> String {
         let allowed = Set("0123456789bcdefghjkmnpqrstuvwxyz")
         return s
-            .trimmingCharacters(in: .whitespacesAndNewlines)
+            .trimmed
             .lowercased()
             .replacingOccurrences(of: "#", with: "")
             .filter { allowed.contains($0) }

bitchat/Services/MessageDeduplicationService.swift

@@ -145,7 +145,7 @@ enum ContentNormalizer {
         }
 
         // Trim and collapse whitespace
-        let trimmed = simplified.trimmingCharacters(in: .whitespacesAndNewlines)
+        let trimmed = simplified.trimmed
         let collapsed = trimmed.replacingOccurrences(of: "\\s+", with: " ", options: .regularExpression)
 
         // Take prefix and hash

bitchat/Utils/InputValidator.swift

@@ -21,9 +21,7 @@ struct InputValidator {
     /// Rejects strings containing control characters to prevent potential security issues
     /// and UI rendering problems. This strict approach ensures data integrity at input time.
     static func validateUserString(_ string: String, maxLength: Int) -> String? {
-        let trimmed = string.trimmingCharacters(in: .whitespacesAndNewlines)
-        guard !trimmed.isEmpty else { return nil }
-        guard trimmed.count <= maxLength else { return nil }
+        guard let trimmed = string.trimmedOrNilIfEmpty, trimmed.count <= maxLength else { return nil }
 
         // Reject control characters outright instead of rewriting the string.
         // This prevents injection attacks and ensures consistent UI rendering.

bitchat/Utils/String+Ext.swift

@@ -0,0 +1,22 @@
+//
+// String+Ext.swift
+// bitchat
+//
+// This is free and unencumbered software released into the public domain.
+// For more information, see <https://unlicense.org>
+//
+
+extension StringProtocol {
+    var trimmed: String {
+        trimmingCharacters(in: .whitespacesAndNewlines)
+    }
+
+    var trimmedOrNilIfEmpty: String? {
+        let trimmed = self.trimmed
+        return trimmed.isEmpty ? nil : trimmed
+    }
+
+    var nilIfEmpty: Self? {
+        isEmpty ? nil : self
+    }
+}

bitchat/ViewModels/ChatViewModel.swift

@@ -144,10 +144,11 @@ final class ChatViewModel: ObservableObject, BitchatDelegate, CommandContextProv
     private let networkResetGraceSeconds: TimeInterval = TransportConfig.networkResetGraceSeconds // avoid refiring on short drops/reconnects
     @Published var nickname: String = "" {
         didSet {
-            // Trim whitespace whenever nickname is set
-            let trimmed = nickname.trimmingCharacters(in: .whitespacesAndNewlines)
+            // Trim whitespace whenever nickname is set; whitespace-only becomes ""
+            let trimmed = nickname.trimmedOrNilIfEmpty ?? ""
             if trimmed != nickname {
                 nickname = trimmed
+                return
             }
             // Update mesh service nickname if it's initialized
             if !meshService.myPeerID.isEmpty {
@@ -747,8 +748,7 @@ final class ChatViewModel: ObservableObject, BitchatDelegate, CommandContextProv
     
     private func loadNickname() {
         if let savedNickname = userDefaults.string(forKey: nicknameKey) {
-            // Trim whitespace when loading
-            nickname = savedNickname.trimmingCharacters(in: .whitespacesAndNewlines)
+            nickname = savedNickname.trimmed
         } else {
             nickname = "anon\(Int.random(in: 1000...9999))"
             saveNickname()
@@ -764,20 +764,10 @@ final class ChatViewModel: ObservableObject, BitchatDelegate, CommandContextProv
     }
     
     func validateAndSaveNickname() {
-        // Trim whitespace from nickname
-        let trimmed = nickname.trimmingCharacters(in: .whitespacesAndNewlines)
-        
-        // Check if nickname is empty after trimming
-        if trimmed.isEmpty {
-            nickname = "anon\(Int.random(in: 1000...9999))"
-        } else {
-            nickname = trimmed
-        }
+        nickname = nickname.trimmedOrNilIfEmpty ?? "anon\(Int.random(in: 1000...9999))"
         saveNickname()
     }
-    
-    // MARK: - Favorites Management
-    
+
     // MARK: - Blocked Users Management (Delegated to PeerStateManager)
     
     
@@ -998,8 +988,7 @@ final class ChatViewModel: ObservableObject, BitchatDelegate, CommandContextProv
     @MainActor
     func sendMessage(_ content: String) {
         // Ignore messages that are empty or whitespace-only to prevent blank lines
-        let trimmed = content.trimmingCharacters(in: .whitespacesAndNewlines)
-        guard !trimmed.isEmpty else { return }
+        guard let trimmed = content.trimmedOrNilIfEmpty else { return }
 
         // Check for commands
         if content.hasPrefix("/") {
@@ -3002,7 +2991,7 @@ final class ChatViewModel: ObservableObject, BitchatDelegate, CommandContextProv
         Task { @MainActor in
             // Early validation
             guard !isMessageBlocked(message) else { return }
-            guard !message.content.trimmingCharacters(in: .whitespacesAndNewlines).isEmpty || message.isPrivate else { return }
+            guard !message.content.trimmed.isEmpty || message.isPrivate else { return }
             
             // Route to appropriate handler
             if message.isPrivate {
@@ -3175,7 +3164,7 @@ final class ChatViewModel: ObservableObject, BitchatDelegate, CommandContextProv
 
     func didReceivePublicMessage(from peerID: PeerID, nickname: String, content: String, timestamp: Date, messageID: String?) {
         Task { @MainActor in
-            let normalized = content.trimmingCharacters(in: .whitespacesAndNewlines)
+            let normalized = content.trimmed
             let publicMentions = parseMentions(from: normalized)
             let msg = BitchatMessage(
                 id: messageID,
@@ -3783,10 +3772,8 @@ final class ChatViewModel: ObservableObject, BitchatDelegate, CommandContextProv
         // Removed background nudge notification for generic "new chats!"
 
         // Append via batching buffer (skip empty content) with simple dedup by ID
-        if !finalMessage.content.trimmingCharacters(in: .whitespacesAndNewlines).isEmpty {
-            if !messages.contains(where: { $0.id == finalMessage.id }) {
-                publicMessagePipeline.enqueue(finalMessage)
-            }
+        if !finalMessage.content.trimmed.isEmpty, !messages.contains(where: { $0.id == finalMessage.id }) {
+            publicMessagePipeline.enqueue(finalMessage)
         }
     }
     

bitchat/ViewModels/Extensions/ChatViewModel+Nostr.swift

@@ -77,7 +77,7 @@ extension ChatViewModel {
         }
         
         if let nickTag = event.tags.first(where: { $0.first == "n" }), nickTag.count >= 2 {
-            let nick = nickTag[1].trimmingCharacters(in: .whitespacesAndNewlines)
+            let nick = nickTag[1].trimmed
             geoNicknames[event.pubkey.lowercased()] = nick
         }
         
@@ -115,8 +115,8 @@ extension ChatViewModel {
         }
         
         let senderName = displayNameForNostrPubkey(event.pubkey)
-        let content = event.content.trimmingCharacters(in: .whitespacesAndNewlines)
-        
+        let content = event.content.trimmed
+
         // Clamp future timestamps to now to avoid future-dated messages skewing order
         let rawTs = Date(timeIntervalSince1970: TimeInterval(event.created_at))
         let timestamp = min(rawTs, Date())
@@ -192,7 +192,7 @@ extension ChatViewModel {
         case .mesh:
             refreshVisibleMessages(from: .mesh)
             // Debug: log if any empty messages are present
-            let emptyMesh = messages.filter { $0.content.trimmingCharacters(in: .whitespacesAndNewlines).isEmpty }.count
+            let emptyMesh = messages.filter { $0.content.trimmed.isEmpty }.count
             if emptyMesh > 0 {
                 SecureLogger.debug("RenderGuard: mesh timeline contains \(emptyMesh) empty messages", category: .session)
             }
@@ -308,8 +308,7 @@ extension ChatViewModel {
         
         // Cache nickname from tag if present
         if let nickTag = event.tags.first(where: { $0.first == "n" }), nickTag.count >= 2 {
-            let nick = nickTag[1].trimmingCharacters(in: .whitespacesAndNewlines)
-            geoNicknames[event.pubkey.lowercased()] = nick
+            geoNicknames[event.pubkey.lowercased()] = nickTag[1].trimmed
         }
         
         // Store mapping for geohash DM initiation
@@ -325,8 +324,10 @@ extension ChatViewModel {
         let content = event.content
         
         // If this is a teleport presence event (no content), don't add to timeline
-        if let teleTag = event.tags.first(where: { $0.first == "t" }), teleTag.count >= 2, (teleTag[1] == "teleport"),
-           content.trimmingCharacters(in: .whitespacesAndNewlines).isEmpty {
+        if let teleTag = event.tags.first(where: { $0.first == "t" }),
+           teleTag.count >= 2,
+           teleTag[1] == "teleport",
+           content.trimmed.isEmpty {
             return
         }
         
@@ -496,9 +497,8 @@ extension ChatViewModel {
         participantTracker.recordParticipant(pubkeyHex: event.pubkey, geohash: gh)
         
         // Notify only on rising-edge: previously zero people, now someone sends a chat
-        let content = event.content.trimmingCharacters(in: .whitespacesAndNewlines)
-        guard !content.isEmpty else { return }
-        
+        guard let content = event.content.trimmedOrNilIfEmpty else { return }
+
         // Respect geohash blocks
         if identityManager.isNostrBlocked(pubkeyHexLowercased: event.pubkey.lowercased()) { return }
         

bitchat/ViewModels/Extensions/ChatViewModel+PrivateChat.swift

@@ -548,13 +548,15 @@ extension ChatViewModel {
     func cleanupLocalFile(forMessage message: BitchatMessage) {
         // Check both outgoing and incoming directories for thorough cleanup
         let categories: [MimeType.Category] = [.audio, .image, .file]
-        guard let category = categories.first(where: { message.content.hasPrefix($0.messagePrefix) }) else { return }
-        let rawFilename = String(message.content.dropFirst(category.messagePrefix.count)).trimmingCharacters(in: .whitespacesAndNewlines)
-        guard !rawFilename.isEmpty, let base = try? applicationFilesDirectory() else { return }
-
-        // Security: Extract only the last path component to prevent directory traversal
-        let safeFilename = (rawFilename as NSString).lastPathComponent
-        guard !safeFilename.isEmpty && safeFilename != "." && safeFilename != ".." else { return }
+        guard let category = categories.first(where: { message.content.hasPrefix($0.messagePrefix) }),
+              let rawFilename = String(message.content.dropFirst(category.messagePrefix.count)).trimmedOrNilIfEmpty,
+              let base = try? applicationFilesDirectory(),
+              // Security: Extract only the last path component to prevent directory traversal
+              let safeFilename = (rawFilename as NSString).lastPathComponent.nilIfEmpty,
+              safeFilename != "." && safeFilename != ".."
+        else {
+            return
+        }
 
         // Try all possible locations (outgoing and incoming)
         let subdirs = categories.flatMap { ["\($0.mediaDir)/outgoing", "\($0.mediaDir)/incoming"] }

bitchat/Views/ContentView.swift

@@ -361,8 +361,7 @@ struct ContentView: View {
         }()
 
         let messageItems: [MessageDisplayItem] = windowedMessages.compactMap { message in
-            let trimmed = message.content.trimmingCharacters(in: .whitespacesAndNewlines)
-            guard !trimmed.isEmpty else { return nil }
+            guard let trimmed = message.content.trimmedOrNilIfEmpty else { return nil }
             return MessageDisplayItem(id: "\(contextKey)|\(message.id)", message: message)
         }
 
@@ -766,8 +765,7 @@ struct ContentView: View {
     // MARK: - Actions
     
     private func sendMessage() {
-        let trimmed = trimmedMessageText
-        guard !trimmed.isEmpty else { return }
+        guard let trimmed = messageText.trimmedOrNilIfEmpty else { return }
 
         // Clear input immediately for instant feedback
         messageText = ""
@@ -1537,10 +1535,6 @@ private extension ContentView {
         )
     }
 
-    private var trimmedMessageText: String {
-        messageText.trimmingCharacters(in: .whitespacesAndNewlines)
-    }
-
     private var shouldShowMediaControls: Bool {
         if let peer = viewModel.selectedPrivateChatPeer, !(peer.isGeoDM || peer.isGeoChat) {
             return true
@@ -1601,7 +1595,7 @@ private extension ContentView {
 
     @ViewBuilder
     var sendOrMicButton: some View {
-        let hasText = !trimmedMessageText.isEmpty
+        let hasText = !messageText.trimmed.isEmpty
         if shouldShowVoiceControl {
             ZStack {
                 micButtonView

bitchat/Views/LocationChannelsSheet.swift

@@ -302,7 +302,7 @@ struct LocationChannelsSheet: View {
                         }
                     }
                 let normalized = customGeohash
-                    .trimmingCharacters(in: .whitespacesAndNewlines)
+                    .trimmed
                     .lowercased()
                     .replacingOccurrences(of: "#", with: "")
                 let isValid = validateGeohash(normalized)
@@ -449,7 +449,7 @@ struct LocationChannelsSheet: View {
     // Split a title like "#mesh [3 people]" into base and suffix "[3 people]"
     private func splitTitleAndCount(_ s: String) -> (base: String, countSuffix: String?) {
         guard let idx = s.lastIndex(of: "[") else { return (s, nil) }
-        let prefix = String(s[..<idx]).trimmingCharacters(in: .whitespaces)
+        let prefix = String(s[..<idx]).trimmed
         let suffix = String(s[idx...])
         return (prefix, suffix)
     }

bitchat/Views/LocationNotesView.swift

@@ -264,14 +264,13 @@ struct LocationNotesView: View {
     }
 
     private func send() {
-        let content = draft.trimmingCharacters(in: .whitespacesAndNewlines)
-        guard !content.isEmpty else { return }
+        guard let content = draft.trimmedOrNilIfEmpty else { return }
         manager.send(content: content, nickname: viewModel.nickname)
         draft = ""
     }
 
     private var sendButtonEnabled: Bool {
-        !draft.trimmingCharacters(in: .whitespacesAndNewlines).isEmpty && manager.state != .noRelays
+        !draft.trimmed.isEmpty && manager.state != .noRelays
     }
 
     // MARK: - Timestamp Formatting