Gemini Live API 可处理连续的音频或文本流，这些流称为会话。您可以管理会话生命周期，从初始握手到正常终止。
会话限制
对于 Live API，会话是指通过同一连接持续流式传输输入和输出的持久连接。
如果会话超出以下任何限制，连接就会终止。
连接时长限制为大约 10 分钟。
会话时长取决于输入模态：
- 纯音频输入会话的时长上限为 15 分钟。
- 视频和音频输入时长限制为 2 分钟。
会话上下文窗口的上限为 12.8 万个 token。
在关联结束之前，您会收到即将结束的通知，以便您采取进一步的措施。
启动会话
如需查看显示如何开始会话的完整代码段，请参阅 Live API 的入门指南。
在会话期间更新
Live API 模型支持以下高级功能，可用于会话中更新：
添加增量内容更新
您可以在有效会话期间添加增量更新。使用此方法可发送文本输入、建立会话上下文或恢复会话上下文。
对于较长的上下文，建议提供单个消息摘要，以释放上下文窗口，以便进行后续互动。
对于简短的上下文，您可以发送逐轮互动来表示确切的事件序列，如下面的代码段所示。
Swift
// Define initial turns (history/context).
let turns: [ModelContent] = [
ModelContent(role: "user", parts: [TextPart("What is the capital of France?")]),
ModelContent(role: "model", parts: [TextPart("Paris")]),
]
// Send history, keeping the conversational turn OPEN (false).
await session.sendContent(turns, turnComplete: false)
// Define the new user query.
let newTurn: [ModelContent] = [
ModelContent(role: "user", parts: [TextPart("What is the capital of Germany?")]),
]
// Send the final query, CLOSING the turn (true) to trigger the model response.
await session.sendContent(newTurn, turnComplete: true)
Kotlin
Not yet supported for Android apps - check back soon!
Java
Not yet supported for Android apps - check back soon!
Web
const turns = [{ text: "Hello from the user!" }];
await session.send(
turns,
false // turnComplete: false
);
console.log("Sent history. Waiting for next input...");
// Define the new user query.
const newTurn [{ text: "And what is the capital of Germany?" }];
// Send the final query, CLOSING the turn (true) to trigger the model response.
await session.send(
newTurn,
true // turnComplete: true
);
console.log("Sent final query. Model response expected now.");
Dart
// Define initial turns (history/context).
final List turns = [
Content(
"user",
[Part.text("What is the capital of France?")],
),
Content(
"model",
[Part.text("Paris")],
),
];
// Send history, keeping the conversational turn OPEN (false).
await session.send(
input: turns,
turnComplete: false,
);
// Define the new user query.
final List newTurn = [
Content(
"user",
[Part.text("What is the capital of Germany?")],
),
];
// Send the final query, CLOSING the turn (true) to trigger the model response.
await session.send(
input: newTurn,
turnComplete: true,
);
Unity
// Define initial turns (history/context).
List turns = new List {
new ModelContent("user", new ModelContent.TextPart("What is the capital of France?") ),
new ModelContent("model", new ModelContent.TextPart("Paris") ),
};
// Send history, keeping the conversational turn OPEN (false).
foreach (ModelContent turn in turns)
{
await session.SendAsync(
content: turn,
turnComplete: false
);
}
// Define the new user query.
ModelContent newTurn = ModelContent.Text("What is the capital of Germany?");
// Send the final query, CLOSING the turn (true) to trigger the model response.
await session.SendAsync(
content: newTurn,
turnComplete: true
);
在会话中途更新系统指令
| 仅在将 Vertex AI Gemini API 用作 API 提供方时可用。 |
您可以在活跃会话期间更新系统指令。使用此方法可调整模型的回答，例如更改回答语言或修改语气。
如需在会话中途更新系统指令，您可以使用 system 角色发送文本内容。更新后的系统指令将在剩余会话期间保持有效。
Swift
await session.sendContent(
[ModelContent(
role: "system",
parts: [TextPart("new system instruction")]
)],
turnComplete: false
)
Kotlin
Not yet supported for Android apps - check back soon!
Java
Not yet supported for Android apps - check back soon!
Web
Not yet supported for Web apps - check back soon!
Dart
try {
await _session.send(
input: Content(
'system',
[Part.text('new system instruction')],
),
turnComplete: false,
);
} catch (e) {
print('Failed to update system instructions: $e');
}
Unity
try
{
await session.SendAsync(
content: new ModelContent(
"system",
new ModelContent.TextPart("new system instruction")
),
turnComplete: false
);
}
catch (Exception e)
{
Debug.LogError($"Failed to update system instructions: {e.Message}");
}
检测会话何时结束
系统会在会话结束前
以下示例展示了如何通过监听 going away 通知来检测即将发生的会话终止：
Swift
for try await response in session.responses {
switch response.payload {
case .goingAwayNotice(let goingAwayNotice):
// Prepare for the session to close soon
if let timeLeft = goingAwayNotice.timeLeft {
print("Server going away in \(timeLeft) seconds")
}
}
}
Kotlin
for (response in session.responses) {
when (val message = response.payload) {
is LiveServerGoAway -> {
// Prepare for the session to close soon
val remaining = message.timeLeft
logger.info("Server going away in $remaining")
}
}
}
Java
session.getResponses().forEach(response -> {
if (response.getPayload() instanceof LiveServerResponse.GoingAwayNotice) {
LiveServerResponse.GoingAwayNotice notice = (LiveServerResponse.GoingAwayNotice) response.getPayload();
// Prepare for the session to close soon
Duration timeLeft = notice.getTimeLeft();
}
});
Web
for await (const message of session.receive()) {
switch (message.type) {
...
case "goingAwayNotice":
console.log("Server going away. Time left:", message.timeLeft);
break;
}
}
Dart
Future _handleLiveServerMessage(LiveServerResponse response) async {
final message = response.message;
if (message is GoingAwayNotice) {
// Prepare for the session to close soon
developer.log('Server going away. Time left: ${message.timeLeft}');
}
}
Unity
foreach (var response in session.Responses) {
if (response.Payload is LiveSessionGoingAway notice) {
// Prepare for the session to close soon
TimeSpan timeLeft = notice.TimeLeft;
Debug.Log($"Server going away notice received. Remaining: {timeLeft}");
}
}