Vision client libraries

This page shows how to get started with the Cloud Client Libraries for the Vision API. Client libraries make it easier to access Google Cloud APIs from a supported language. Although you can use Google Cloud APIs directly by making raw requests to the server, client libraries provide simplifications that significantly reduce the amount of code you need to write.

Read more about the Cloud Client Libraries and the older Google API Client Libraries in Client libraries explained.

Note: Additional client libraries are available for Java applications.

Install the client library

C++

See Setting up a C++ development environment for details about this client library's requirements and install dependencies.

C#

If you are using Visual Studio 2017 or higher, open nuget package manager window and type the following:

Install-Package Google.Apis

If you are using .NET Core command-line interface tools to install your dependencies, run the following command:

dotnet add package Google.Apis

For more information, see Setting Up a C# Development Environment.

Go

go get cloud.google.com/go/vision/apiv1

For more information, see Setting Up a Go Development Environment.

Java

Note: If your application uses the Spring Framework, a Spring module is also available.

If you are using Maven, add the following to your pom.xml file. For more information about BOMs, see The Google Cloud Platform Libraries BOM.

<dependencyManagement>
  <dependencies>
    <dependency>
      <groupId>com.google.cloud</groupId>
      <artifactId>libraries-bom</artifactId>
      <version>26.49.0</version>
      <type>pom</type>
      <scope>import</scope>
    </dependency>
  </dependencies>
</dependencyManagement>

<dependencies>
  <dependency>
    <groupId>com.google.cloud</groupId>
    <artifactId>google-cloud-vision</artifactId>
  </dependency>
</dependencies>

If you are using Gradle, add the following to your dependencies:

implementation 'com.google.cloud:google-cloud-vision:3.50.0'

If you are using sbt, add the following to your dependencies:

libraryDependencies += "com.google.cloud" % "google-cloud-vision" % "3.50.0"

If you're using Visual Studio Code, IntelliJ, or Eclipse, you can add client libraries to your project using the following IDE plugins:

• Cloud Code for VS Code
• Cloud Code for IntelliJ
• Cloud Tools for Eclipse

The plugins provide additional functionality, such as key management for service accounts. Refer to each plugin's documentation for details.

Note: Cloud Java client libraries do not currently support Android.

For more information, see Setting Up a Java Development Environment.

Node.js

npm install --save @google-cloud/vision

For more information, see Setting Up a Node.js Development Environment.

PHP

composer require google/apiclient

For more information, see Using PHP on Google Cloud.

Python

Note: See the migration guide for information about migrating to Python client library v0.25.1.

pip install --upgrade google-cloud-vision

For more information, see Setting Up a Python Development Environment.

Ruby

gem install google-api-client

For more information, see Setting Up a Ruby Development Environment.

Set up authentication

To authenticate calls to Google Cloud APIs, client libraries support Application Default Credentials (ADC); the libraries look for credentials in a set of defined locations and use those credentials to authenticate requests to the API. With ADC, you can make credentials available to your application in a variety of environments, such as local development or production, without needing to modify your application code.

For production environments, the way you set up ADC depends on the service and context. For more information, see Set up Application Default Credentials.

For a local development environment, you can set up ADC with the credentials that are associated with your Google Account:

1. Install the Google Cloud CLI, then initialize it by running the following command:

   gcloud init

2. If you're using a local shell, then create local authentication credentials for your user account:

   gcloud auth application-default login

   You don't need to do this if you're using Cloud Shell.

   A sign-in screen appears. After you sign in, your credentials are stored in the local credential file used by ADC.

Use the client library

The following example shows how to use the client library.

C++

#include "google/cloud/vision/v1/image_annotator_client.h"
#include <iostream>

int main(int argc, char* argv[]) try {
  auto constexpr kDefaultUri =
      "gs://cloud-samples-data/vision/label/wakeupcat.jpg";
  if (argc > 2) {
    std::cerr << "Usage: " << argv[0] << " [gcs-uri]\n"
              << "  The gcs-uri must be in gs://... format. It defaults to "
              << kDefaultUri << "\n";
    return 1;
  }
  auto uri = std::string{argc == 2 ? argv[1] : kDefaultUri};

  namespace vision = ::google::cloud::vision_v1;
  auto client =
      vision::ImageAnnotatorClient(vision::MakeImageAnnotatorConnection());

  // Define the image we want to annotate
  google::cloud::vision::v1::Image image;
  image.mutable_source()->set_image_uri(uri);
  // Create a request to annotate this image with Request text annotations for a
  // file stored in GCS.
  google::cloud::vision::v1::AnnotateImageRequest request;
  *request.mutable_image() = std::move(image);
  request.add_features()->set_type(
      google::cloud::vision::v1::Feature::TEXT_DETECTION);

  google::cloud::vision::v1::BatchAnnotateImagesRequest batch_request;
  *batch_request.add_requests() = std::move(request);
  auto batch = client.BatchAnnotateImages(batch_request);
  if (!batch) throw std::move(batch).status();

  // Find the longest annotation and print it
  auto result = std::string{};
  for (auto const& response : batch->responses()) {
    for (auto const& annotation : response.text_annotations()) {
      if (result.size() < annotation.description().size()) {
        result = annotation.description();
      }
    }
  }
  std::cout << "The image contains this text: " << result << "\n";

  return 0;
} catch (google::cloud::Status const& status) {
  std::cerr << "google::cloud::Status thrown: " << status << "\n";
  return 1;
}

Go

// Sample vision-quickstart uses the Google Cloud Vision API to label an image.
package main

import (
	"context"
	"fmt"
	"log"
	"os"

	vision "cloud.google.com/go/vision/apiv1"
)

func main() {
	ctx := context.Background()

	// Creates a client.
	client, err := vision.NewImageAnnotatorClient(ctx)
	if err != nil {
		log.Fatalf("Failed to create client: %v", err)
	}
	defer client.Close()

	// Sets the name of the image file to annotate.
	filename := "../testdata/cat.jpg"

	file, err := os.Open(filename)
	if err != nil {
		log.Fatalf("Failed to read file: %v", err)
	}
	defer file.Close()
	image, err := vision.NewImageFromReader(file)
	if err != nil {
		log.Fatalf("Failed to create image: %v", err)
	}

	labels, err := client.DetectLabels(ctx, image, nil, 10)
	if err != nil {
		log.Fatalf("Failed to detect labels: %v", err)
	}

	fmt.Println("Labels:")
	for _, label := range labels {
		fmt.Println(label.Description)
	}
}

Java

// Imports the Google Cloud client library

import com.google.cloud.vision.v1.AnnotateImageRequest;
import com.google.cloud.vision.v1.AnnotateImageResponse;
import com.google.cloud.vision.v1.BatchAnnotateImagesResponse;
import com.google.cloud.vision.v1.EntityAnnotation;
import com.google.cloud.vision.v1.Feature;
import com.google.cloud.vision.v1.Feature.Type;
import com.google.cloud.vision.v1.Image;
import com.google.cloud.vision.v1.ImageAnnotatorClient;
import com.google.protobuf.ByteString;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.Paths;
import java.util.ArrayList;
import java.util.List;

public class QuickstartSample {
  public static void main(String... args) throws Exception {
    // Initialize client that will be used to send requests. This client only needs to be created
    // once, and can be reused for multiple requests. After completing all of your requests, call
    // the "close" method on the client to safely clean up any remaining background resources.
    try (ImageAnnotatorClient vision = ImageAnnotatorClient.create()) {

      // The path to the image file to annotate
      String fileName = "./resources/wakeupcat.jpg";

      // Reads the image file into memory
      Path path = Paths.get(fileName);
      byte[] data = Files.readAllBytes(path);
      ByteString imgBytes = ByteString.copyFrom(data);

      // Builds the image annotation request
      List<AnnotateImageRequest> requests = new ArrayList<>();
      Image img = Image.newBuilder().setContent(imgBytes).build();
      Feature feat = Feature.newBuilder().setType(Type.LABEL_DETECTION).build();
      AnnotateImageRequest request =
          AnnotateImageRequest.newBuilder().addFeatures(feat).setImage(img).build();
      requests.add(request);

      // Performs label detection on the image file
      BatchAnnotateImagesResponse response = vision.batchAnnotateImages(requests);
      List<AnnotateImageResponse> responses = response.getResponsesList();

      for (AnnotateImageResponse res : responses) {
        if (res.hasError()) {
          System.out.format("Error: %s%n", res.getError().getMessage());
          return;
        }

        for (EntityAnnotation annotation : res.getLabelAnnotationsList()) {
          annotation
              .getAllFields()
              .forEach((k, v) -> System.out.format("%s : %s%n", k, v.toString()));
        }
      }
    }
  }
}

Node.js

async function quickstart() {
  // Imports the Google Cloud client library
  const vision = require('@google-cloud/vision');

  // Creates a client
  const client = new vision.ImageAnnotatorClient();

  // Performs label detection on the image file
  const [result] = await client.labelDetection('./resources/wakeupcat.jpg');
  const labels = result.labelAnnotations;
  console.log('Labels:');
  labels.forEach(label => console.log(label.description));
}
quickstart();

Python

# Imports the Google Cloud client library
from google.cloud import vision



def run_quickstart() -> vision.EntityAnnotation:
    """Provides a quick start example for Cloud Vision."""

    # Instantiates a client
    client = vision.ImageAnnotatorClient()

    # The URI of the image file to annotate
    file_uri = "gs://cloud-samples-data/vision/label/wakeupcat.jpg"

    image = vision.Image()
    image.source.image_uri = file_uri

    # Performs label detection on the image file
    response = client.label_detection(image=image)
    labels = response.label_annotations

    print("Labels:")
    for label in labels:
        print(label.description)

    return labels

Additional resources

C++

The following list contains links to more resources related to the client library for C++:

• API reference
• Client libraries best practices
• Issue tracker
• google-cloud-vision on Stack Overflow
• Source code

C#

The following list contains links to more resources related to the client library for C#:

• API reference
• Client libraries best practices
• Issue tracker
• google-cloud-vision on Stack Overflow
• Source code

Go

The following list contains links to more resources related to the client library for Go:

• API reference
• Client libraries best practices
• Issue tracker
• google-cloud-vision on Stack Overflow
• Source code

Java

The following list contains links to more resources related to the client library for Java:

• API reference
• Client libraries best practices
• Issue tracker
• google-cloud-vision on Stack Overflow
• Source code

Node.js

The following list contains links to more resources related to the client library for Node.js:

• API reference
• Client libraries best practices
• Issue tracker
• google-cloud-vision on Stack Overflow
• Source code

PHP

The following list contains links to more resources related to the client library for PHP:

• API reference
• Client libraries best practices
• Issue tracker
• google-cloud-vision on Stack Overflow
• Source code

Python

The following list contains links to more resources related to the client library for Python:

• API reference
• Client libraries best practices
• Issue tracker
• google-cloud-vision on Stack Overflow
• Source code

Ruby

The following list contains links to more resources related to the client library for Ruby:

• API reference
• Client libraries best practices
• Issue tracker
• google-cloud-vision on Stack Overflow
• Source code

Additional client libraries

In addition to the libraries shown above, Spring Cloud Google Cloud is available for Java applications. Spring Vision API helps you use Cloud Vision in any application that's built with the Spring Framework.

To get started, learn how to add Spring Cloud Vision to your application.

Try it for yourself

If you're new to Google Cloud, create an account to evaluate how Cloud Vision API performs in real-world scenarios. New customers also get $300 in free credits to run, test, and deploy workloads.

Try Cloud Vision API free