Generate text from an image with safety settings

This sample demonstrates how to use the Gemini model with safety settings to generate text from an image.

Code sample

C#

Before trying this sample, follow the C# setup instructions in the Vertex AI quickstart using client libraries. For more information, see the Vertex AI C# API reference documentation.

To authenticate to Vertex AI, set up Application Default Credentials. For more information, see Set up authentication for a local development environment. 


using Google.Api.Gax.Grpc;
using Google.Cloud.AIPlatform.V1;
using System.Text;
using System.Threading.Tasks;
using static Google.Cloud.AIPlatform.V1.SafetySetting.Types;

public class WithSafetySettings
{
    public async Task<string> GenerateContent(
        string projectId = "your-project-id",
        string location = "us-central1",
        string publisher = "google",
        string model = "gemini-2.0-flash-001"
    )
    {
        var predictionServiceClient = new PredictionServiceClientBuilder
        {
            Endpoint = $"{location}-aiplatform.googleapis.com"
        }.Build();


        var generateContentRequest = new GenerateContentRequest
        {
            Model = $"projects/{projectId}/locations/{location}/publishers/{publisher}/models/{model}",
            Contents =
            {
                new Content
                {
                    Role = "USER",
                    Parts =
                    {
                        new Part { Text = "Hello!" }
                    }
                }
            },
            SafetySettings =
            {
                new SafetySetting
                {
                    Category = HarmCategory.HateSpeech,
                    Threshold = HarmBlockThreshold.BlockLowAndAbove
                },
                new SafetySetting
                {
                    Category = HarmCategory.DangerousContent,
                    Threshold = HarmBlockThreshold.BlockMediumAndAbove
                }
            }
        };

        using PredictionServiceClient.StreamGenerateContentStream response = predictionServiceClient.StreamGenerateContent(generateContentRequest);

        StringBuilder fullText = new();

        AsyncResponseStream<GenerateContentResponse> responseStream = response.GetResponseStream();
        await foreach (GenerateContentResponse responseItem in responseStream)
        {
            // Check if the content has been blocked for safety reasons.
            bool blockForSafetyReason = responseItem.Candidates[0].FinishReason == Candidate.Types.FinishReason.Safety;
            if (blockForSafetyReason)
            {
                fullText.Append("Blocked for safety reasons");
            }
            else
            {
                fullText.Append(responseItem.Candidates[0].Content.Parts[0].Text);
            }
        }

        return fullText.ToString();
    }
}

Node.js

Before trying this sample, follow the Node.js setup instructions in the Vertex AI quickstart using client libraries. For more information, see the Vertex AI Node.js API reference documentation.

To authenticate to Vertex AI, set up Application Default Credentials. For more information, see Set up authentication for a local development environment. 

const {
  VertexAI,
  HarmCategory,
  HarmBlockThreshold,
} = require('@google-cloud/vertexai');

/**
 * TODO(developer): Update these variables before running the sample.
 */
const PROJECT_ID = process.env.CAIP_PROJECT_ID;
const LOCATION = 'us-central1';
const MODEL = 'gemini-2.0-flash-001';

async function setSafetySettings() {
  // Initialize Vertex with your Cloud project and location
  const vertexAI = new VertexAI({project: PROJECT_ID, location: LOCATION});

  // Instantiate the model
  const generativeModel = vertexAI.getGenerativeModel({
    model: MODEL,
    // The following parameters are optional
    // They can also be passed to individual content generation requests
    safetySettings: [
      {
        category: HarmCategory.HARM_CATEGORY_DANGEROUS_CONTENT,
        threshold: HarmBlockThreshold.BLOCK_LOW_AND_ABOVE,
      },
      {
        category: HarmCategory.HARM_CATEGORY_HARASSMENT,
        threshold: HarmBlockThreshold.BLOCK_LOW_AND_ABOVE,
      },
    ],
  });

  const request = {
    contents: [{role: 'user', parts: [{text: 'Tell me something dangerous.'}]}],
  };

  console.log('Prompt:');
  console.log(request.contents[0].parts[0].text);
  console.log('Streaming Response Text:');

  // Create the response stream
  const responseStream = await generativeModel.generateContentStream(request);

  // Log the text response as it streams
  for await (const item of responseStream.stream) {
    if (item.candidates[0].finishReason === 'SAFETY') {
      console.log('This response stream terminated due to safety concerns.');
      break;
    } else {
      process.stdout.write(item.candidates[0].content.parts[0].text);
    }
  }
  console.log('This response stream terminated due to safety concerns.');
}

What's next

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