Added opt-in sharing of feature usage with self-hosted servers (#1020)

Co-authored-by: Thorsten Sommer <SommerEngineering@users.noreply.github.com>

app/MindWork AI Studio/Tools/AppUserAgent.cs

@@ -0,0 +1,117 @@
+using System.Globalization;
+using System.Net.Http.Headers;
+using System.Reflection;
+using System.Text;
+
+using AIStudio.Chat;
+using AIStudio.Provider;
+using AIStudio.Settings;
+using AIStudio.Tools.Metadata;
+
+using SharedTools;
+
+namespace AIStudio.Tools;
+
+/// <summary>
+/// The User-Agent which AI Studio sends to self-hosted servers, when the user allows it.
+/// </summary>
+/// <remarks>
+/// It lets the operators of a self-hosted server or a gateway such as LiteLLM tell requests from
+/// AI Studio apart from other clients, e.g., in their logs, and see which feature sent them.<br/><br/>
+/// Who receives it is decided in IsAllowedFor, and nowhere else: only self-hosted servers, and only
+/// when the user or their organization switched on sharing the feature usage. Without that, AI Studio
+/// sends no User-Agent at all, the same as before this existed. Cloud providers never receive it.
+/// </remarks>
+public static class AppUserAgent
+{
+    private static readonly MetaDataAttribute META_DATA = Assembly.GetExecutingAssembly().GetCustomAttribute<MetaDataAttribute>()!;
+
+    /// <summary>
+    /// The User-Agent naming the app, its version, and the platform, e.g., <c>MindWorkAIStudio/26.9.1 (osx-arm64)</c>.
+    /// </summary>
+    public static readonly string BASE = CreateBase();
+
+    /// <summary>
+    /// Whether requests to the given provider may carry the User-Agent.
+    /// </summary>
+    /// <param name="provider">The provider which receives the requests.</param>
+    /// <param name="settingsManager">The settings, which say whether the user shares the feature usage.</param>
+    /// <returns>True when the provider runs on a self-hosted server and sharing is switched on; otherwise, false.</returns>
+    public static bool IsAllowedFor(LLMProviders provider, SettingsManager settingsManager) =>
+        provider.RunsOnSelfHostedServer() && settingsManager.ConfigurationData.App.ShareFeatureUsageWithSelfHostedServerOperators;
+
+    /// <summary>
+    /// Sets the User-Agent as default header of the given HTTP client.
+    /// </summary>
+    /// <param name="httpClient">The HTTP client, whose requests should carry the User-Agent.</param>
+    public static void Apply(HttpClient httpClient) => httpClient.DefaultRequestHeaders.UserAgent.TryParseAdd(BASE);
+
+    /// <summary>
+    /// Replaces the User-Agent of a single request by one naming the component of the given chat thread.
+    /// </summary>
+    /// <param name="headers">The headers of the request.</param>
+    /// <param name="chatThread">The chat thread, whose component sent the request.</param>
+    public static void ApplyComponent(HttpRequestHeaders headers, ChatThread chatThread)
+    {
+        headers.Remove("User-Agent");
+        headers.TryAddWithoutValidation("User-Agent", ForComponent(chatThread.RuntimeComponent, chatThread.RuntimeAssistantName));
+    }
+
+    /// <summary>
+    /// Creates the User-Agent naming the given component, e.g., <c>MindWorkAIStudio/26.9.1 (osx-arm64) Component/TRANSLATION_ASSISTANT</c>.
+    /// </summary>
+    /// <param name="component">The component which sends the request.</param>
+    /// <param name="assistantName">The name of the assistant plugin, if any.</param>
+    /// <returns>The User-Agent.</returns>
+    public static string ForComponent(Components component, string assistantName = "")
+    {
+        if (component is Components.NONE)
+            return BASE;
+
+        var userAgent = $"{BASE} Component/{component}";
+        var assistantToken = ToProductToken(assistantName);
+        return string.IsNullOrWhiteSpace(assistantToken)
+            ? userAgent
+            : $"{userAgent} Assistant/{assistantToken}";
+    }
+
+    /// <summary>
+    /// Converts a free-text name into a valid product token of a User-Agent.
+    /// </summary>
+    /// <remarks>
+    /// Header values are ASCII only, and a product token must not contain separators like spaces,
+    /// slashes, or parentheses. Diacritics are dropped (Ü becomes U), everything else is replaced by a dash.
+    /// </remarks>
+    private static string ToProductToken(string name)
+    {
+        if (string.IsNullOrWhiteSpace(name))
+            return string.Empty;
+
+        const int MAX_LENGTH = 64;
+        var normalized = name.Trim().Replace("ß", "ss").Normalize(NormalizationForm.FormD);
+        var token = new StringBuilder(normalized.Length);
+        foreach (var character in normalized)
+        {
+            if (CharUnicodeInfo.GetUnicodeCategory(character) is UnicodeCategory.NonSpacingMark)
+                continue;
+
+            if (char.IsAsciiLetterOrDigit(character) || character is '.' or '_' or '-')
+                token.Append(character);
+            else if (token.Length > 0 && token[^1] is not '-')
+                token.Append('-');
+
+            if (token.Length >= MAX_LENGTH)
+                break;
+        }
+
+        return token.ToString().TrimEnd('-');
+    }
+
+    private static string CreateBase()
+    {
+        var rid = RIDExtensions.GetCurrentRID().AsMicrosoftRid();
+        return string.IsNullOrWhiteSpace(rid)
+            ? $"MindWorkAIStudio/{META_DATA.Version}"
+            : $"MindWorkAIStudio/{META_DATA.Version} ({rid})";
+    }
+}