LiveGenerativeModel.cs

/*
 * Copyright 2025 Google LLC
 *
 * 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.
 */

usingSystem;
usingSystem.Collections.Generic;
usingSystem.Linq;
usingSystem.Net.WebSockets;
usingSystem.Text;
usingSystem.Threading;
usingSystem.Threading.Tasks;
usingFirebase.VertexAI.Internal;
usingGoogle.MiniJSON;

namespaceFirebase.VertexAI{

/// <summary>
/// A live, generative AI model for real-time interaction.
///
/// See the [Cloud
/// documentation](https://cloud.google.com/vertex-ai/generative-ai/docs/model-reference/multimodal-live)
/// for more details about the low-latency, two-way interactions that use text,
/// audio, and video input, with audio and text output.
///
/// > Warning: For Vertex AI in Firebase, Live Model
/// is in Public Preview, which means that the feature is not subject to any SLA
/// or deprecation policy and could change in backwards-incompatible ways.
/// </summary>
publicclassLiveGenerativeModel{
privatereadonlyFirebaseApp_firebaseApp;

// Various setting fields provided by the user.
privatereadonlyFirebaseAI.Backend_backend;
privatereadonlystring_modelName;
privatereadonlyLiveGenerationConfig?_liveConfig;
privatereadonlyTool[]_tools;
privatereadonlyModelContent?_systemInstruction;
privatereadonlyRequestOptions?_requestOptions;

/// <summary>
/// Intended for internal use only.
/// Use `VertexAI.GetLiveModel` instead to ensure proper initialization and configuration of the `LiveGenerativeModel`.
/// </summary>
internalLiveGenerativeModel(FirebaseAppfirebaseApp,
FirebaseAI.Backendbackend,
stringmodelName,
LiveGenerationConfig?liveConfig=null,
Tool[]tools=null,
ModelContent?systemInstruction=null,
RequestOptions?requestOptions=null){
_firebaseApp=firebaseApp;
_backend=backend;
_modelName=modelName;
_liveConfig=liveConfig;
_tools=tools;
_systemInstruction=systemInstruction;
_requestOptions=requestOptions;
}

privatestringGetURL(){
return"wss://firebasevertexai.googleapis.com/ws"+
"/google.firebase.vertexai.v1beta.LlmBidiService/BidiGenerateContent"+
$"/locations/{_backend.Location}"+
$"?key={_firebaseApp.Options.ApiKey}";
}

/// <summary>
/// Establishes a connection to a live generation service.
///
/// This function handles the WebSocket connection setup and returns an `LiveSession`
/// object that can be used to communicate with the service.
/// </summary>
/// <param name="cancellationToken">The token that can be used to cancel the creation of the session.</param>
/// <returns>The LiveSession, once it is established.</returns>
publicasyncTask<LiveSession>ConnectAsync(CancellationTokencancellationToken=default){
ClientWebSocketclientWebSocket=new();

stringendpoint=GetURL();

// Set initial headers
// TODO: Get the Version from the Firebase.VersionInfo.SdkVersion (requires exposing it via App)
clientWebSocket.Options.SetRequestHeader("x-goog-api-client","genai-csharp/0.1.0");
// Add additional Firebase tokens to the header.
awaitFirebaseInterops.AddFirebaseTokensAsync(clientWebSocket,_firebaseApp);

// Add a timeout to the initial connection, using the RequestOptions.
usingvarconnectionCts=CancellationTokenSource.CreateLinkedTokenSource(cancellationToken);
TimeSpanconnectionTimeout=_requestOptions?.Timeout??RequestOptions.DefaultTimeout;
connectionCts.CancelAfter(connectionTimeout);

awaitclientWebSocket.ConnectAsync(newUri(endpoint),connectionCts.Token);

if(clientWebSocket.State!=WebSocketState.Open){
thrownewWebSocketException("ClientWebSocket failed to connect, can't create LiveSession.");
}

try{
// Send the initial setup message
Dictionary<string,object>setupDict=new(){
{"model",$"projects/{_firebaseApp.Options.ProjectId}/locations/{_backend.Location}/publishers/google/models/{_modelName}"}
};
if(_liveConfig!=null){
setupDict["generationConfig"]=_liveConfig?.ToJson();
}
if(_systemInstruction.HasValue){
setupDict["systemInstruction"]=_systemInstruction?.ToJson();
}
if(_tools!=null&&_tools.Length>0){
setupDict["tools"]=_tools.Select(t =>t.ToJson()).ToList();
}
Dictionary<string,object>jsonDict=new(){
{"setup",setupDict}
};

varbyteArray=Encoding.UTF8.GetBytes(Json.Serialize(jsonDict));
awaitclientWebSocket.SendAsync(newArraySegment<byte>(byteArray),WebSocketMessageType.Binary,true,cancellationToken);

returnnewLiveSession(clientWebSocket);
}catch(Exception){
if(clientWebSocket.State==WebSocketState.Open){
// Try to clean up the WebSocket, to avoid leaking connections.
awaitclientWebSocket.CloseAsync(WebSocketCloseStatus.EndpointUnavailable,
"Failed to send initial setup message.",CancellationToken.None);
}
throw;
}
}
}

}