Fixes #225 - Use a properly defined user agent

* Set a proper user agent
* Add fallback when UA comes out nil
* Remove unused Bundle extension
* Return nil when asciification fails
* Add whitespace handling and further emoji test case
* Explicitly check if string is already in ASCII
* Rename factory to builder
* Use allSatisfy instead of reduce
* Use key path syntax

ElementX/Sources/Other/Extensions/String.swift

@@ -51,4 +51,22 @@ extension String {
         }
         return abs(hash)
     }
+    
+    var isASCII: Bool {
+        allSatisfy(\.isASCII)
+    }
+    
+    func asciified() -> String? {
+        guard !isASCII else {
+            return self
+        }
+        guard !canBeConverted(to: .ascii) else {
+            return nil
+        }
+        let mutableString = NSMutableString(string: self)
+        guard CFStringTransform(mutableString, nil, "Any-Latin; Latin-ASCII; [:^ASCII:] Remove" as CFString, false) else {
+            return nil
+        }
+        return mutableString.trimmingCharacters(in: .whitespaces)
+    }
 }

ElementX/Sources/Other/UserAgentBuilder.swift

@@ -0,0 +1,71 @@
+//
+// Copyright 2022 New Vector Ltd
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+//
+
+import Foundation
+import UIKit
+
+#if !os(OSX)
+import DeviceKit
+#endif
+
+final class UserAgentBuilder {
+    class func makeASCIIUserAgent() -> String? {
+        makeUserAgent()?.asciified()
+    }
+    
+    private class func makeUserAgent() -> String? {
+        let clientName = ElementInfoPlist.cfBundleDisplayName
+        let clientVersion = ElementInfoPlist.cfBundleShortVersionString
+
+        #if os(iOS)
+        return String(
+            format: "%@/%@ (%@; iOS %@; Scale/%0.2f)",
+            clientName,
+            clientVersion,
+            Device.current.safeDescription,
+            UIDevice.current.systemVersion,
+            UIScreen.main.scale
+        )
+        #elseif os(tvOS)
+        return String(
+            format: "%@/%@ (%@; tvOS %@; Scale/%0.2f)",
+            clientName,
+            clientVersion,
+            Device.current.safeDescription,
+            UIDevice.current.systemVersion,
+            UIScreen.main.scale
+        )
+        #elseif os(watchOS)
+        return String(
+            format: "%@/%@ (%@; watchOS %@; Scale/%0.2f)",
+            clientName,
+            clientVersion,
+            Device.current.safeDescription,
+            WKInterfaceDevice.current.systemVersion,
+            WKInterfaceDevice.currentDevice.screenScale
+        )
+        #elseif os(OSX)
+        return String(
+            format: "%@/%@ (Mac; Mac OS X %@)",
+            clientName,
+            clientVersion,
+            NSProcessInfo.processInfo.operatingSystemVersionString
+        )
+        #else
+        return nil
+        #endif
+    }
+}

ElementX/Sources/Services/UserSessionStore/UserSessionStore.swift

@@ -109,7 +109,8 @@ class UserSessionStore: UserSessionStoreProtocol {
         let builder = ClientBuilder()
             .basePath(path: baseDirectory.path)
             .username(username: credentials.userID)
-        
+            .userAgent(userAgent: UserAgentBuilder.makeASCIIUserAgent() ?? "unknown")
+
         do {
             let client: Client = try await Task.dispatch(on: .global()) {
                 let client = try builder.build()