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# 将调用模型 API 与响应流搭配使用在 Amazon Bedrock 上调用 Cohere Command R 和 R\$1
以下代码示例演示了如何将调用模型 API 与响应流搭配使用向 Cohere Command 发送文本消息。
------
#### [ .NET ]
**适用于 .NET 的 SDK**
还有更多相关信息 GitHub。在 [AWS 代码示例存储库](https://github.com/awsdocs/aws-doc-sdk-examples/tree/main/dotnetv3/Bedrock-runtime#code-examples)中查找完整示例，了解如何进行设置和运行。
使用调用模型 API 发送文本消息并实时处理响应流。
```
// Use the native inference API to send a text message to Cohere Command R
// and print the response stream.
using System;
using System.IO;
using System.Text.Json;
using System.Text.Json.Nodes;
using Amazon;
using Amazon.BedrockRuntime;
using Amazon.BedrockRuntime.Model;
// Create a Bedrock Runtime client in the AWS Region you want to use.
var client = new AmazonBedrockRuntimeClient(RegionEndpoint.USEast1);
// Set the model ID, e.g., Command R.
var modelId = "cohere.command-r-v1:0";
// Define the user message.
var userMessage = "Describe the purpose of a 'hello world' program in one line.";
//Format the request payload using the model's native structure.
var nativeRequest = JsonSerializer.Serialize(new
{
message = userMessage,
max_tokens = 512,
temperature = 0.5
});
// Create a request with the model ID and the model's native request payload.
var request = new InvokeModelWithResponseStreamRequest()
{
ModelId = modelId,
Body = new MemoryStream(System.Text.Encoding.UTF8.GetBytes(nativeRequest)),
ContentType = "application/json"
};
try
{
// Send the request to the Bedrock Runtime and wait for the response.
var streamingResponse = await client.InvokeModelWithResponseStreamAsync(request);
// Extract and print the streamed response text in real-time.
foreach (var item in streamingResponse.Body)
{
var chunk = JsonSerializer.Deserialize((item as PayloadPart).Bytes);
var text = chunk["text"] ?? "";
Console.Write(text);
}
}
catch (AmazonBedrockRuntimeException e)
{
Console.WriteLine($"ERROR: Can't invoke '{modelId}'. Reason: {e.Message}");
throw;
}
```
+ 有关 API 的详细信息，请参阅 *适用于 .NET 的 AWS SDK API 参考[InvokeModel](https://docs.aws.amazon.com/goto/DotNetSDKV3/bedrock-runtime-2023-09-30/InvokeModel)*中的。
------
#### [ Java ]
**适用于 Java 的 SDK 2.x**
还有更多相关信息 GitHub。在 [AWS 代码示例存储库](https://github.com/awsdocs/aws-doc-sdk-examples/tree/main/javav2/example_code/bedrock-runtime#code-examples)中查找完整示例，了解如何进行设置和运行。
使用调用模型 API 发送文本消息并实时处理响应流。
```
// Use the native inference API to send a text message to Cohere Command R
// and print the response stream.
import org.json.JSONObject;
import org.json.JSONPointer;
import software.amazon.awssdk.auth.credentials.DefaultCredentialsProvider;
import software.amazon.awssdk.core.SdkBytes;
import software.amazon.awssdk.regions.Region;
import software.amazon.awssdk.services.bedrockruntime.BedrockRuntimeAsyncClient;
import software.amazon.awssdk.services.bedrockruntime.model.InvokeModelWithResponseStreamRequest;
import software.amazon.awssdk.services.bedrockruntime.model.InvokeModelWithResponseStreamResponseHandler;
import java.util.concurrent.ExecutionException;
import static software.amazon.awssdk.services.bedrockruntime.model.InvokeModelWithResponseStreamResponseHandler.Visitor;
public class Command_R_InvokeModelWithResponseStream {
public static String invokeModelWithResponseStream() {
// Create a Bedrock Runtime client in the AWS Region you want to use.
// Replace the DefaultCredentialsProvider with your preferred credentials provider.
var client = BedrockRuntimeAsyncClient.builder()
.credentialsProvider(DefaultCredentialsProvider.create())
.region(Region.US_EAST_1)
.build();
// Set the model ID, e.g., Command R.
var modelId = "cohere.command-r-v1:0";
// The InvokeModelWithResponseStream API uses the model's native payload.
// Learn more about the available inference parameters and response fields at:
// https://docs.aws.amazon.com/bedrock/latest/userguide/model-parameters-cohere-command-r-plus.html
var nativeRequestTemplate = "{ \"message\": \"{{prompt}}\" }";
// Define the prompt for the model.
var prompt = "Describe the purpose of a 'hello world' program in one line.";
// Embed the prompt in the model's native request payload.
String nativeRequest = nativeRequestTemplate.replace("{{prompt}}", prompt);
// Create a request with the model ID and the model's native request payload.
var request = InvokeModelWithResponseStreamRequest.builder()
.body(SdkBytes.fromUtf8String(nativeRequest))
.modelId(modelId)
.build();
// Prepare a buffer to accumulate the generated response text.
var completeResponseTextBuffer = new StringBuilder();
// Prepare a handler to extract, accumulate, and print the response text in real-time.
var responseStreamHandler = InvokeModelWithResponseStreamResponseHandler.builder()
.subscriber(Visitor.builder().onChunk(chunk -> {
// Extract and print the text from the model's native response.
var response = new JSONObject(chunk.bytes().asUtf8String());
var text = new JSONPointer("/text").queryFrom(response);
System.out.print(text);
// Append the text to the response text buffer.
completeResponseTextBuffer.append(text);
}).build()).build();
try {
// Send the request and wait for the handler to process the response.
client.invokeModelWithResponseStream(request, responseStreamHandler).get();
// Return the complete response text.
return completeResponseTextBuffer.toString();
} catch (ExecutionException | InterruptedException e) {
System.err.printf("Can't invoke '%s': %s", modelId, e.getCause().getMessage());
throw new RuntimeException(e);
}
}
public static void main(String[] args) throws ExecutionException, InterruptedException {
invokeModelWithResponseStream();
}
}
```
+ 有关 API 的详细信息，请参阅 *AWS SDK for Java 2.x API 参考[InvokeModel](https://docs.aws.amazon.com/goto/SdkForJavaV2/bedrock-runtime-2023-09-30/InvokeModel)*中的。
------
#### [ Python ]
**适用于 Python 的 SDK（Boto3）**
还有更多相关信息 GitHub。在 [AWS 代码示例存储库](https://github.com/awsdocs/aws-doc-sdk-examples/tree/main/python/example_code/bedrock-runtime#code-examples)中查找完整示例，了解如何进行设置和运行。
使用调用模型 API 发送文本消息并实时处理响应流。
```
# Use the native inference API to send a text message to Cohere Command R and R+
# and print the response stream.
import boto3
import json
from botocore.exceptions import ClientError
# Create a Bedrock Runtime client in the AWS Region of your choice.
client = boto3.client("bedrock-runtime", region_name="us-east-1")
# Set the model ID, e.g., Command R.
model_id = "cohere.command-r-v1:0"
# Define the prompt for the model.
prompt = "Describe the purpose of a 'hello world' program in one line."
# Format the request payload using the model's native structure.
native_request = {
"message": prompt,
"max_tokens": 512,
"temperature": 0.5,
}
# Convert the native request to JSON.
request = json.dumps(native_request)
try:
# Invoke the model with the request.
streaming_response = client.invoke_model_with_response_stream(
modelId=model_id, body=request
)
# Extract and print the response text in real-time.
for event in streaming_response["body"]:
chunk = json.loads(event["chunk"]["bytes"])
if "generations" in chunk:
print(chunk["generations"][0]["text"], end="")
except (ClientError, Exception) as e:
print(f"ERROR: Can't invoke '{model_id}'. Reason: {e}")
exit(1)
```
+ 有关 API 的详细信息，请参阅适用[InvokeModel](https://docs.aws.amazon.com/goto/boto3/bedrock-runtime-2023-09-30/InvokeModel)于 *Python 的AWS SDK (Boto3) API 参考*。
------
有关 S AWS DK 开发者指南和代码示例的完整列表，请参阅[将 Amazon Bedrock 与 SD AWS K 配合使用](sdk-general-information-section.md)。本主题还包括有关入门的信息以及有关先前的 SDK 版本的详细信息。