Quickstart: Using Client Libraries

This page shows you how to get started with the Cloud Vision API in your favorite programming language using the Google Cloud Client Libraries.

Before you begin

1. Sign in to your Google Account.

   If you don't already have one, sign up for a new account.

2. Select or create a Google Cloud Platform project.

   Note: If you don't plan to keep the resources you create in this tutorial, create a new project instead of selecting an existing project. After you finish, you can delete the project, removing all resources associated with the project and tutorial.

   Go to the Manage resources page

3. Verifica che la fatturazione sia attivata per il tuo progetto.

   scopri come attivare la fatturazione

4. Enable the Cloud Vision API.

   Enable the API

5. Set up authentication:

   1. In the GCP Console, go to the Create service account key page.

      Go to the Create Service Account Key page
   2. From the Service account list, select New service account.
   3. In the Service account name field, enter a name.

   4. From the Role list, select Project > Owner.

      Note: The Role field authorizes your service account to access resources. You can view and change this field later by using the GCP Console. If you are developing a production app, specify more granular permissions than Project > Owner. For more information, see granting roles to service accounts.
   5. Click Create. A JSON file that contains your key downloads to your computer.

6. Set the environment variable GOOGLE_APPLICATION_CREDENTIALS to the file path of the JSON file that contains your service account key. This variable only applies to your current shell session, so if you open a new session, set the variable again.

   Example: Linux or macOS

   Replace [PATH] with the file path of the JSON file that contains your service account key.

   export GOOGLE_APPLICATION_CREDENTIALS="[PATH]"

   For example:

   export GOOGLE_APPLICATION_CREDENTIALS="/home/user/Downloads/service-account-file.json"

   Example: Windows

   Replace [PATH] with the file path of the JSON file that contains your service account key, and [FILE_NAME] with the filename.

   With PowerShell:

   $env:GOOGLE_APPLICATION_CREDENTIALS="[PATH]"

   For example:

   $env:GOOGLE_APPLICATION_CREDENTIALS="C:\Users\username\Downloads\[FILE_NAME].json"

   With command prompt:

   set GOOGLE_APPLICATION_CREDENTIALS=[PATH]

Install the client library

C#

For more on setting up your C# development environment, refer to the C# Development Environment Setup Guide.

Install-Package Google.Cloud.Vision.V1 -Pre

Go

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

Java

For more on setting up your Java development environment, refer to the Java Development Environment Setup Guide. If you are using Maven, add the following to your pom.xml file:

<dependency>
  <groupId>com.google.cloud</groupId>
  <artifactId>google-cloud-vision</artifactId>
  <version>1.77.0</version>
</dependency>

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

compile 'com.google.cloud:google-cloud-vision:1.77.0'

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

libraryDependencies += "com.google.cloud" % "google-cloud-vision" % "1.77.0"

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

• Cloud Tools 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.

Node.js

For more on setting up your Node.js development environment, refer to the Node.js Development Environment Setup Guide.

npm install --save @google-cloud/vision

PHP

composer require google/cloud-vision

Python

For more on setting up your Python development environment, refer to the Python Development Environment Setup Guide.

pip install --upgrade google-cloud-vision

Ruby

For more on setting up your Ruby development environment, refer to the Ruby Development Environment Setup Guide.

gem install google-cloud-vision

Label detection

Now you can use the Vision API to request information from an image, such as label detection. Run the following code to perform your first image label detection request:

C#

Before trying this sample, follow the C# setup instructions in the Vision API Quickstart Using Client Libraries . For more information, see the Vision API C# API reference documentation .

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using Google.Cloud.Vision.V1;
using System;

namespace GoogleCloudSamples
{
    public class QuickStart
    {
        public static void Main(string[] args)
        {
            // Instantiates a client
            var client = ImageAnnotatorClient.Create();
            // Load the image file into memory
            var image = Image.FromFile("wakeupcat.jpg");
            // Performs label detection on the image file
            var response = client.DetectLabels(image);
            foreach (var annotation in response)
            {
                if (annotation.Description != null)
                    Console.WriteLine(annotation.Description);
            }
        }
    }
}

Go

Before trying this sample, follow the Go setup instructions in the Vision API Quickstart Using Client Libraries . For more information, see the Vision API Go API reference documentation .

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// 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

Before trying this sample, follow the Java setup instructions in the Vision API Quickstart Using Client Libraries . For more information, see the Vision API Java API reference documentation .

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// 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 {
    // Instantiates a client
    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.printf("Error: %s\n", res.getError().getMessage());
          return;
        }

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

Node.js

Before trying this sample, follow the Node.js setup instructions in the Vision API Quickstart Using Client Libraries . For more information, see the Vision API Node.js API reference documentation .

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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));
}

PHP

Before trying this sample, follow the PHP setup instructions in the Vision API Quickstart Using Client Libraries . For more information, see the Vision API PHP API reference documentation .

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# includes the autoloader for libraries installed with composer
require __DIR__ . '/vendor/autoload.php';

# imports the Google Cloud client library
use Google\Cloud\Vision\V1\ImageAnnotatorClient;

# instantiates a client
$imageAnnotator = new ImageAnnotatorClient();

# the name of the image file to annotate
$fileName = 'test/data/wakeupcat.jpg';

# prepare the image to be annotated
$image = file_get_contents($fileName);

# performs label detection on the image file
$response = $imageAnnotator->labelDetection($image);
$labels = $response->getLabelAnnotations();

if ($labels) {
    echo("Labels:" . PHP_EOL);
    foreach ($labels as $label) {
        echo($label->getDescription() . PHP_EOL);
    }
} else {
    echo('No label found' . PHP_EOL);
}

Python

Before trying this sample, follow the Python setup instructions in the Vision API Quickstart Using Client Libraries . For more information, see the Vision API Python API reference documentation .

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import io
import os

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

# Instantiates a client
client = vision.ImageAnnotatorClient()

# The name of the image file to annotate
file_name = os.path.join(
    os.path.dirname(__file__),
    'resources/wakeupcat.jpg')

# Loads the image into memory
with io.open(file_name, 'rb') as image_file:
    content = image_file.read()

image = types.Image(content=content)

# 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)

Ruby

Before trying this sample, follow the Ruby setup instructions in the Vision API Quickstart Using Client Libraries . For more information, see the Vision API Ruby API reference documentation .

View on GitHub Feedback

# Imports the Google Cloud client library
require "google/cloud/vision"

# Instantiates a client
image_annotator = Google::Cloud::Vision::ImageAnnotator.new

# The name of the image file to annotate
file_name = "./resources/cat.jpg"

# Performs label detection on the image file
response = image_annotator.label_detection image: file_name
response.responses.each do |res|
  puts "Labels:"
  res.label_annotations.each do |label|
    puts label.description
  end
end

Congratulations! You've sent your first request to the Vision API.

It worked!

Great! What did you like about the quickstart? What could we have done better? Let us know!.

I got stuck!

Bummer. Let us know what went wrong. We'll want to fix it.

Clean up

To avoid incurring charges to your Google Cloud Platform account for the resources used in this quickstart:

• Use the GCP Console to delete your project if you do not need it.

What's next

Find out more about our Cloud Vision API Client Libraries.