[VertexAI] Add support for Developer API (#1233)

* [VertexAI] Add support for Developer API

* Update GenerativeModel.cs

* Throw error on BiDi on GoogleAI, and comments

Author: a-maurice

vertexai/src/Candidate.cs

@@ -125,13 +125,14 @@ private static FinishReason ParseFinishReason(string str) {
   /// Intended for internal use only.
   /// This method is used for deserializing JSON responses and should not be called directly.
   /// </summary>
-  internal static Candidate FromJson(Dictionary<string, object> jsonDict) {
+  internal static Candidate FromJson(Dictionary<string, object> jsonDict,
+      FirebaseAI.Backend.InternalProvider backend) {
     return new Candidate(
       jsonDict.ParseObject("content", ModelContent.FromJson, defaultValue: new ModelContent("model")),
       jsonDict.ParseObjectList("safetyRatings", SafetyRating.FromJson),
       jsonDict.ParseNullableEnum("finishReason", ParseFinishReason),
       jsonDict.ParseNullableObject("citationMetadata",
-          Firebase.VertexAI.CitationMetadata.FromJson));
+          (d) => Firebase.VertexAI.CitationMetadata.FromJson(d, backend)));
   }
 }
 

vertexai/src/Citation.cs

@@ -42,9 +42,16 @@ private CitationMetadata(List<Citation> citations) {
   /// Intended for internal use only.
   /// This method is used for deserializing JSON responses and should not be called directly.
   /// </summary>
-  internal static CitationMetadata FromJson(Dictionary<string, object> jsonDict) {
+  internal static CitationMetadata FromJson(Dictionary<string, object> jsonDict,
+      FirebaseAI.Backend.InternalProvider backend) {
+    string citationKey = backend switch {
+      FirebaseAI.Backend.InternalProvider.GoogleAI => "citationSources",
+      FirebaseAI.Backend.InternalProvider.VertexAI => "citations",
+      _ => throw new ArgumentOutOfRangeException(nameof(backend), backend,
+                         "Unsupported or unhandled backend provider encountered.")
+    };
     return new CitationMetadata(
-      jsonDict.ParseObjectList("citations", Citation.FromJson));
+      jsonDict.ParseObjectList(citationKey, Citation.FromJson));
   }
 }
 

vertexai/src/VertexAI.cs renamed to vertexai/src/FirebaseAI.cs

@@ -20,60 +20,108 @@
 namespace Firebase.VertexAI {
 
 /// <summary>
-/// The entry point for all Vertex AI in Firebase functionality.
+/// The entry point for all Firebase AI SDK functionality.
 /// </summary>
-public class VertexAI {
+public class FirebaseAI {
 
-  private static readonly ConcurrentDictionary<string, VertexAI> _instances = new();
+  /// <summary>
+  /// Defines which backend AI service is being used, provided to `FirebaseAI.GetInstance`.
+  /// </summary>
+  public readonly struct Backend {
+    /// <summary>
+    /// Intended for internal use only.
+    /// Defines the possible types of backend providers.
+    /// </summary>
+    internal enum InternalProvider {
+      GoogleAI,
+      VertexAI
+    }
+
+    /// <summary>
+    /// Intended for internal use only.
+    /// The backend provider being used.
+    /// </summary>
+    internal InternalProvider Provider { get; }
+    /// <summary>
+    /// Intended for internal use only.
+    /// The region identifier used by the Vertex AI backend.
+    /// </summary>
+    internal string Location { get; }
+
+    private Backend(InternalProvider provider, string location = null) {
+      Provider = provider;
+      Location = location;
+    }
+
+    /// <summary>
+    /// The Google AI backend service configuration.
+    /// </summary>
+    public static Backend GoogleAI() {
+      return new Backend(InternalProvider.GoogleAI);
+    }
+
+    /// <summary>
+    /// The Vertex AI backend service configuration.
+    /// </summary>
+    /// <param name="location">The region identifier, defaulting to `us-central1`; see [Vertex AI
+    ///     regions](https://cloud.google.com/vertex-ai/generative-ai/docs/learn/locations#available-regions)
+    ///     for a list of supported regions.</param>
+    public static Backend VertexAI(string location = "us-central1") {
+      if (string.IsNullOrWhiteSpace(location) || location.Contains("/")) {
+        throw new VertexAIInvalidLocationException(location);
+      }
+
+      return new Backend(InternalProvider.VertexAI, location);
+    }
+
+    public override readonly string ToString() {
+      return $"FirebaseAIBackend|{Provider}|{Location}";
+    }
+  }
+
+  private static readonly ConcurrentDictionary<string, FirebaseAI> _instances = new();
 
-  private FirebaseApp _firebaseApp;
-  private string _location;
+  private readonly FirebaseApp _firebaseApp;
+  private readonly Backend _backend;
 
-  private VertexAI(FirebaseApp firebaseApp, string location) {
+  private FirebaseAI(FirebaseApp firebaseApp, Backend backend) {
     _firebaseApp = firebaseApp;
-    _location = location;
+    _backend = backend;
   }
 
   /// <summary>
-  /// Returns a `VertexAI` instance initialized with the default `FirebaseApp` and location.
+  /// Returns a `FirebaseAI` instance with the default `FirebaseApp` and GoogleAI Backend.
   /// </summary>
-  public static VertexAI DefaultInstance => GetInstance();
+  public static FirebaseAI DefaultInstance => GetInstance();
 
   /// <summary>
-  /// Creates an instance of `VertexAI` configured with the default `FirebaseApp`, and the given location.
+  /// Returns a `FirebaseAI` instance with the default `FirebaseApp` and the given Backend.
   /// </summary>
-  /// <param name="location">The region identifier, defaulting to `us-central1`; see [Vertex AI
-  ///     regions](https://cloud.google.com/vertex-ai/generative-ai/docs/learn/locations#available-regions)
-  ///     for a list of supported regions.</param>
-  /// <returns>A configured instance of `VertexAI`.</returns>
-  public static VertexAI GetInstance(string location = "us-central1") {
-    return GetInstance(FirebaseApp.DefaultInstance, location);
+  /// <param name="backend">The backend AI service to use.</param>
+  /// <returns>A configured instance of `FirebaseAI`.</returns>
+  public static FirebaseAI GetInstance(Backend? backend = null) {
+    return GetInstance(FirebaseApp.DefaultInstance, backend);
   }
-
   /// <summary>
-  /// Creates an instance of `VertexAI` configured with the given `FirebaseApp` and location.
+  /// Returns a `FirebaseAI` instance with the given `FirebaseApp` and Backend.
   /// </summary>
   /// <param name="app">The custom `FirebaseApp` used for initialization.</param>
-  /// <param name="location">The region identifier, defaulting to `us-central1`; see [Vertex AI
-  ///     regions](https://cloud.google.com/vertex-ai/generative-ai/docs/learn/locations#available-regions)
-  ///     for a list of supported regions.</param>
-  /// <returns>A configured instance of `VertexAI`.</returns>
-  public static VertexAI GetInstance(FirebaseApp app, string location = "us-central1") {
+  /// <param name="backend">The backend AI service to use.</param>
+  /// <returns>A configured instance of `FirebaseAI`.</returns>
+  public static FirebaseAI GetInstance(FirebaseApp app, Backend? backend = null) {
     if (app == null) {
       throw new ArgumentNullException(nameof(app));
     }
 
-    if (string.IsNullOrWhiteSpace(location) || location.Contains("/")) {
-      throw new VertexAIInvalidLocationException(location);
-    }
+    Backend resolvedBackend = backend ?? Backend.GoogleAI();
 
-    // VertexAI instances are keyed by a combination of the app name and location.
-    string key = $"{app.Name}::{location}";
+    // FirebaseAI instances are keyed by a combination of the app name and backend.
+    string key = $"{app.Name}::{resolvedBackend}";
     if (_instances.ContainsKey(key)) {
       return _instances[key];
     }
 
-    return _instances.GetOrAdd(key, _ => new VertexAI(app, location));
+    return _instances.GetOrAdd(key, _ => new FirebaseAI(app, resolvedBackend));
   }
 
   /// <summary>
@@ -102,7 +150,7 @@ public GenerativeModel GetGenerativeModel(
       ToolConfig? toolConfig = null,
       ModelContent? systemInstruction = null,
       RequestOptions? requestOptions = null) {
-    return new GenerativeModel(_firebaseApp, _location, modelName,
+    return new GenerativeModel(_firebaseApp, _backend, modelName,
         generationConfig, safetySettings, tools,
         toolConfig, systemInstruction, requestOptions);
   }
@@ -112,6 +160,8 @@ public GenerativeModel GetGenerativeModel(
   /// 
   /// - Note: Refer to [Gemini models](https://firebase.google.com/docs/vertex-ai/gemini-models) for
   /// guidance on choosing an appropriate model for your use case.
+  /// 
+  /// - Note: Currently only supports the VertexAI backend.
   /// </summary>
   /// <param name="modelName">The name of the model to use, for example `"gemini-2.0-flash-live-preview-04-09"`; see
   ///     [available model names
@@ -128,7 +178,11 @@ public LiveGenerativeModel GetLiveModel(
       Tool[] tools = null,
       ModelContent? systemInstruction = null,
       RequestOptions? requestOptions = null) {
-    return new LiveGenerativeModel(_firebaseApp, _location, modelName,
+    if (_backend.Provider != Backend.InternalProvider.VertexAI) {
+      throw new NotSupportedException("LiveGenerativeModel is currently only supported with the VertexAI backend.");
+    }
+
+    return new LiveGenerativeModel(_firebaseApp, _backend, modelName,
         liveGenerationConfig, tools,
         systemInstruction, requestOptions);
   }

vertexai/src/VertexAI.cs.meta renamed to vertexai/src/FirebaseAI.cs.meta

@@ -78,17 +78,19 @@ private GenerateContentResponse(List<Candidate> candidates, PromptFeedback? prom
   /// Intended for internal use only.
   /// This method is used for deserializing JSON responses and should not be called directly.
   /// </summary>
-  internal static GenerateContentResponse FromJson(string jsonString) {
-    return FromJson(Json.Deserialize(jsonString) as Dictionary<string, object>);
+  internal static GenerateContentResponse FromJson(string jsonString,
+      FirebaseAI.Backend.InternalProvider backend) {
+    return FromJson(Json.Deserialize(jsonString) as Dictionary<string, object>, backend);
   }
 
   /// <summary>
   /// Intended for internal use only.
   /// This method is used for deserializing JSON responses and should not be called directly.
   /// </summary>
-  internal static GenerateContentResponse FromJson(Dictionary<string, object> jsonDict) {
+  internal static GenerateContentResponse FromJson(Dictionary<string, object> jsonDict,
+      FirebaseAI.Backend.InternalProvider backend) {
     return new GenerateContentResponse(
-      jsonDict.ParseObjectList("candidates", Candidate.FromJson),
+      jsonDict.ParseObjectList("candidates", (d) => Candidate.FromJson(d, backend)),
       jsonDict.ParseNullableObject("promptFeedback",
           Firebase.VertexAI.PromptFeedback.FromJson),
       jsonDict.ParseNullableObject("usageMetadata",

vertexai/src/GenerateContentResponse.cs

@@ -34,7 +34,7 @@ public class GenerativeModel {
   private readonly FirebaseApp _firebaseApp;
 
   // Various setting fields provided by the user.
-  private readonly string _location;
+  private readonly FirebaseAI.Backend _backend;
   private readonly string _modelName;
   private readonly GenerationConfig? _generationConfig;
   private readonly SafetySetting[] _safetySettings;
@@ -52,7 +52,7 @@ public class GenerativeModel {
   /// Use `VertexAI.GetGenerativeModel` instead to ensure proper initialization and configuration of the `GenerativeModel`.
   /// </summary>
   internal GenerativeModel(FirebaseApp firebaseApp,
-                           string location,
+                           FirebaseAI.Backend backend,
                            string modelName,
                            GenerationConfig? generationConfig = null,
                            SafetySetting[] safetySettings = null,
@@ -61,7 +61,7 @@ internal GenerativeModel(FirebaseApp firebaseApp,
                            ModelContent? systemInstruction = null,
                            RequestOptions? requestOptions = null) {
     _firebaseApp = firebaseApp;
-    _location = location;
+    _backend = backend;
     _modelName = modelName;
     _generationConfig = generationConfig;
     _safetySettings = safetySettings;
@@ -195,7 +195,7 @@ private async Task<GenerateContentResponse> GenerateContentAsyncInternal(
     SetRequestHeaders(request);
 
     // Set the content
-    string bodyJson = ModelContentsToJson(content);
+    string bodyJson = MakeGenerateContentRequest(content);
     request.Content = new StringContent(bodyJson, Encoding.UTF8, "application/json");
 
 #if FIREBASE_LOG_REST_CALLS
@@ -219,7 +219,7 @@ private async Task<GenerateContentResponse> GenerateContentAsyncInternal(
     UnityEngine.Debug.Log("Response:\n" + result);
 #endif
 
-    return GenerateContentResponse.FromJson(result);
+    return GenerateContentResponse.FromJson(result, _backend.Provider);
   }
 
   private async IAsyncEnumerable<GenerateContentResponse> GenerateContentStreamAsyncInternal(
@@ -230,7 +230,7 @@ private async IAsyncEnumerable<GenerateContentResponse> GenerateContentStreamAsy
     SetRequestHeaders(request);
 
     // Set the content
-    string bodyJson = ModelContentsToJson(content);
+    string bodyJson = MakeGenerateContentRequest(content);
     request.Content = new StringContent(bodyJson, Encoding.UTF8, "application/json");
 
 #if FIREBASE_LOG_REST_CALLS
@@ -260,7 +260,7 @@ private async IAsyncEnumerable<GenerateContentResponse> GenerateContentStreamAsy
         UnityEngine.Debug.Log("Streaming Response:\n" + line);
 #endif
 
-        yield return GenerateContentResponse.FromJson(line[StreamPrefix.Length..]);
+        yield return GenerateContentResponse.FromJson(line[StreamPrefix.Length..], _backend.Provider);
       }
     }
   }
@@ -301,10 +301,18 @@ private async Task<CountTokensResponse> CountTokensAsyncInternal(
   }
 
   private string GetURL() {
-    return "https://firebasevertexai.googleapis.com/v1beta" +
-        "/projects/" + _firebaseApp.Options.ProjectId +
-        "/locations/" + _location +
-        "/publishers/google/models/" + _modelName;
+    if (_backend.Provider == FirebaseAI.Backend.InternalProvider.VertexAI) {
+      return "https://firebasevertexai.googleapis.com/v1beta" +
+          "/projects/" + _firebaseApp.Options.ProjectId +
+          "/locations/" + _backend.Location +
+          "/publishers/google/models/" + _modelName;
+    } else if (_backend.Provider == FirebaseAI.Backend.InternalProvider.GoogleAI) {
+      return "https://firebasevertexai.googleapis.com/v1beta" +
+          "/projects/" + _firebaseApp.Options.ProjectId +
+          "/models/" + _modelName;
+    } else {
+      throw new NotSupportedException($"Missing support for backend: {_backend.Provider}");
+    }
   }
 
   private void SetRequestHeaders(HttpRequestMessage request) {
@@ -313,7 +321,13 @@ private void SetRequestHeaders(HttpRequestMessage request) {
     request.Headers.Add("x-goog-api-client", "genai-csharp/0.1.0");
   }
 
-  private string ModelContentsToJson(IEnumerable<ModelContent> contents) {
+  private string MakeGenerateContentRequest(IEnumerable<ModelContent> contents) {
+    Dictionary<string, object> jsonDict = MakeGenerateContentRequestAsDictionary(contents);
+    return Json.Serialize(jsonDict);
+  }
+
+  private Dictionary<string, object> MakeGenerateContentRequestAsDictionary(
+      IEnumerable<ModelContent> contents) {
     Dictionary<string, object> jsonDict = new() {
       // Convert the Contents into a list of Json dictionaries
       ["contents"] = contents.Select(c => c.ToJson()).ToList()
@@ -322,7 +336,7 @@ private string ModelContentsToJson(IEnumerable<ModelContent> contents) {
       jsonDict["generationConfig"] = _generationConfig?.ToJson();
     }
     if (_safetySettings != null && _safetySettings.Length > 0) {
-      jsonDict["safetySettings"] = _safetySettings.Select(s => s.ToJson()).ToList();
+      jsonDict["safetySettings"] = _safetySettings.Select(s => s.ToJson(_backend.Provider)).ToList();
     }
     if (_tools != null && _tools.Length > 0) {
       jsonDict["tools"] = _tools.Select(t => t.ToJson()).ToList();
@@ -334,23 +348,38 @@ private string ModelContentsToJson(IEnumerable<ModelContent> contents) {
       jsonDict["systemInstruction"] = _systemInstruction?.ToJson();
     }
 
-    return Json.Serialize(jsonDict);
+    return jsonDict;
   }
 
   // CountTokensRequest is a subset of the full info needed for GenerateContent
   private string MakeCountTokensRequest(IEnumerable<ModelContent> contents) {
-    Dictionary<string, object> jsonDict = new() {
-      // Convert the Contents into a list of Json dictionaries
-      ["contents"] = contents.Select(c => c.ToJson()).ToList()
-    };
-    if (_generationConfig.HasValue) {
-      jsonDict["generationConfig"] = _generationConfig?.ToJson();
-    }
-    if (_tools != null && _tools.Length > 0) {
-      jsonDict["tools"] = _tools.Select(t => t.ToJson()).ToList();
-    }
-    if (_systemInstruction.HasValue) {
-      jsonDict["systemInstruction"] = _systemInstruction?.ToJson();
+    Dictionary<string, object> jsonDict;
+    switch (_backend.Provider) {
+      case FirebaseAI.Backend.InternalProvider.GoogleAI:
+        jsonDict = new() {
+          ["generateContentRequest"] = MakeGenerateContentRequestAsDictionary(contents)
+        };
+        // GoogleAI wants the model name included as well.
+        ((Dictionary<string, object>)jsonDict["generateContentRequest"])["model"] =
+            $"models/{_modelName}";
+        break;
+      case FirebaseAI.Backend.InternalProvider.VertexAI:
+        jsonDict = new() {
+          // Convert the Contents into a list of Json dictionaries
+          ["contents"] = contents.Select(c => c.ToJson()).ToList()
+        };
+        if (_generationConfig.HasValue) {
+          jsonDict["generationConfig"] = _generationConfig?.ToJson();
+        }
+        if (_tools != null && _tools.Length > 0) {
+          jsonDict["tools"] = _tools.Select(t => t.ToJson()).ToList();
+        }
+        if (_systemInstruction.HasValue) {
+          jsonDict["systemInstruction"] = _systemInstruction?.ToJson();
+        }
+        break;
+      default:
+        throw new NotSupportedException($"Missing support for backend: {_backend.Provider}");
     }
 
     return Json.Serialize(jsonDict);