Classifying Content

Content Classification analyzes a document and returns a list of content categories that apply to the text found in the document. To classify the content in a document, call the classifyText method.

A complete list of content categories returned for the classifyText method are found here.

You can choose which model to use for the classifyText method by setting the optional classificationModelOptions field:

This section demonstrates how to classify content in a document. For each document, you must submit a separate request.

Classifying Content

Here is an example of classifying content provided as a string:

Protocol

To classify content from a document, make a POST request to the documents:classifyText REST method and provide the appropriate request body as shown in the following example.

The example uses the gcloud auth application-default print-access-token command to obtain an access token for a service account set up for the project using the Google Cloud Platform gcloud CLI. For instructions on installing the gcloud CLI, setting up a project with a service account see the Quickstart.

curl -X POST \
     -H "Authorization: Bearer "$(gcloud auth application-default print-access-token) \
     -H "Content-Type: application/json; charset=utf-8" \
     --data "{
  'document':{
    'type':'PLAIN_TEXT',
    'content':'Google, headquartered in Mountain View, unveiled the new Android
    phone at the Consumer Electronic Show.  Sundar Pichai said in his keynote
    that users love their new Android phones.'
  },
  'classificationModelOptions': {
    'v2Model': {
      'contentCategoriesVersion': 'V2',
    }
  }
}" "https://language.googleapis.com/v1/documents:classifyText"

Go

To learn how to install and use the client library for Natural Language, see Natural Language client libraries. For more information, see the Natural Language Go API reference documentation.

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


func classifyText(ctx context.Context, client *language.Client, text string) (*languagepb.ClassifyTextResponse, error) {
	return client.ClassifyText(ctx, &languagepb.ClassifyTextRequest{
		Document: &languagepb.Document{
			Source: &languagepb.Document_Content{
				Content: text,
			},
			Type: languagepb.Document_PLAIN_TEXT,
		},
		ClassificationModelOptions: &languagepb.ClassificationModelOptions{
			ModelType: &languagepb.ClassificationModelOptions_V2Model_{
				V2Model: &languagepb.ClassificationModelOptions_V2Model{
					ContentCategoriesVersion: languagepb.ClassificationModelOptions_V2Model_V2,
				},
			},
		},
	})
}

Java

To learn how to install and use the client library for Natural Language, see Natural Language client libraries. For more information, see the Natural Language Java API reference documentation.

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

// Instantiate the Language client com.google.cloud.language.v2.LanguageServiceClient
try (LanguageServiceClient language = LanguageServiceClient.create()) {
  // Set content to the text string
  Document doc = Document.newBuilder().setContent(text).setType(Type.PLAIN_TEXT).build();
  ClassifyTextRequest request = ClassifyTextRequest.newBuilder().setDocument(doc).build();
  // Detect categories in the given text
  ClassifyTextResponse response = language.classifyText(request);

  for (ClassificationCategory category : response.getCategoriesList()) {
    System.out.printf(
        "Category name : %s, Confidence : %.3f\n",
        category.getName(), category.getConfidence());
  }
}

Node.js

To learn how to install and use the client library for Natural Language, see Natural Language client libraries. For more information, see the Natural Language Node.js API reference documentation.

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

// Imports the Google Cloud client library
const language = require('@google-cloud/language');

// Creates a client
const client = new language.LanguageServiceClient();

/**
 * TODO(developer): Uncomment the following line to run this code.
 */
// const text = 'Your text to analyze, e.g. Hello, world!';

// Prepares a document, representing the provided text
const document = {
  content: text,
  type: 'PLAIN_TEXT',
};

const classificationModelOptions = {
  v2Model: {
    contentCategoriesVersion: 'V2',
  },
};

// Classifies text in the document
const [classification] = await client.classifyText({
  document,
  classificationModelOptions,
});
console.log('Categories:');
classification.categories.forEach(category => {
  console.log(`Name: ${category.name}, Confidence: ${category.confidence}`);
});

Python

To learn how to install and use the client library for Natural Language, see Natural Language client libraries. For more information, see the Natural Language Python API reference documentation.

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

from google.cloud import language_v1


def sample_classify_text(text_content):
    """
    Classifying Content in a String

    Args:
      text_content The text content to analyze.
    """

    client = language_v1.LanguageServiceClient()

    # text_content = "That actor on TV makes movies in Hollywood and also stars in a variety of popular new TV shows."

    # Available types: PLAIN_TEXT, HTML
    type_ = language_v1.Document.Type.PLAIN_TEXT

    # Optional. If not specified, the language is automatically detected.
    # For list of supported languages:
    # https://cloud.google.com/natural-language/docs/languages
    language = "en"
    document = {"content": text_content, "type_": type_, "language": language}

    content_categories_version = (
        language_v1.ClassificationModelOptions.V2Model.ContentCategoriesVersion.V2
    )
    response = client.classify_text(
        request={
            "document": document,
            "classification_model_options": {
                "v2_model": {"content_categories_version": content_categories_version}
            },
        }
    )
    # Loop through classified categories returned from the API
    for category in response.categories:
        # Get the name of the category representing the document.
        # See the predefined taxonomy of categories:
        # https://cloud.google.com/natural-language/docs/categories
        print(f"Category name: {category.name}")
        # Get the confidence. Number representing how certain the classifier
        # is that this category represents the provided text.
        print(f"Confidence: {category.confidence}")

Additional languages

C#: Please follow the C# setup instructions on the client libraries page and then visit the Natural Language reference documentation for .NET.

PHP: Please follow the PHP setup instructions on the client libraries page and then visit the Natural Language reference documentation for PHP.

Ruby: Please follow the Ruby setup instructions on the client libraries page and then visit the Natural Language reference documentation for Ruby.

Classifying Content from Cloud Storage

Here is an example of classifying content stored in a text file on Cloud Storage:

Protocol

To classify content from a document stored in Cloud Storage, make a POST request to the documents:classifyText REST method and provide the appropriate request body with the path to the document as shown in the following example.

curl -X POST \
     -H "Authorization: Bearer "$(gcloud auth application-default print-access-token) \
     -H "Content-Type: application/json; charset=utf-8" \
     --data "{
  'document':{
    'type':'PLAIN_TEXT',
    'gcsContentUri':'gs://<bucket-name>/<object-name>'
  }
  'classificationModelOptions': {
    'v1Model': {
    }
  }
}" "https://language.googleapis.com/v1/documents:classifyText"

Go

To learn how to install and use the client library for Natural Language, see Natural Language client libraries. For more information, see the Natural Language Go API reference documentation.

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


func classifyTextFromGCS(ctx context.Context, gcsURI string) (*languagepb.ClassifyTextResponse, error) {
	return client.ClassifyText(ctx, &languagepb.ClassifyTextRequest{
		Document: &languagepb.Document{
			Source: &languagepb.Document_GcsContentUri{
				GcsContentUri: gcsURI,
			},
			Type: languagepb.Document_PLAIN_TEXT,
		},
	})
}

Java

To learn how to install and use the client library for Natural Language, see Natural Language client libraries. For more information, see the Natural Language Java API reference documentation.

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

// Instantiate the Language client com.google.cloud.language.v2.LanguageServiceClient
try (LanguageServiceClient language = LanguageServiceClient.create()) {
  // Set the GCS content URI path
  Document doc =
      Document.newBuilder().setGcsContentUri(gcsUri).setType(Type.PLAIN_TEXT).build();
  ClassifyTextRequest request = ClassifyTextRequest.newBuilder().setDocument(doc).build();
  // Detect categories in the given file
  ClassifyTextResponse response = language.classifyText(request);

  for (ClassificationCategory category : response.getCategoriesList()) {
    System.out.printf(
        "Category name : %s, Confidence : %.3f\n",
        category.getName(), category.getConfidence());
  }
}

Node.js

To learn how to install and use the client library for Natural Language, see Natural Language client libraries. For more information, see the Natural Language Node.js API reference documentation.

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

// Imports the Google Cloud client library.
const language = require('@google-cloud/language');

// Creates a client.
const client = new language.LanguageServiceClient();

/**
 * TODO(developer): Uncomment the following lines to run this code
 */
// const bucketName = 'Your bucket name, e.g. my-bucket';
// const fileName = 'Your file name, e.g. my-file.txt';

// Prepares a document, representing a text file in Cloud Storage
const document = {
  gcsContentUri: `gs://${bucketName}/${fileName}`,
  type: 'PLAIN_TEXT',
};

// Classifies text in the document
const [classification] = await client.classifyText({document});

console.log('Categories:');
classification.categories.forEach(category => {
  console.log(`Name: ${category.name}, Confidence: ${category.confidence}`);
});

Python

To learn how to install and use the client library for Natural Language, see Natural Language client libraries. For more information, see the Natural Language Python API reference documentation.

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

from google.cloud import language_v1


def sample_classify_text(gcs_content_uri):
    """
    Classifying Content in text file stored in Cloud Storage

    Args:
      gcs_content_uri Google Cloud Storage URI where the file content is located.
      e.g. gs://[Your Bucket]/[Path to File]
      The text file must include at least 20 words.
    """

    client = language_v1.LanguageServiceClient()

    # gcs_content_uri = 'gs://cloud-samples-data/language/classify-entertainment.txt'

    # Available types: PLAIN_TEXT, HTML
    type_ = language_v1.Document.Type.PLAIN_TEXT

    # Optional. If not specified, the language is automatically detected.
    # For list of supported languages:
    # https://cloud.google.com/natural-language/docs/languages
    language = "en"
    document = {
        "gcs_content_uri": gcs_content_uri,
        "type_": type_,
        "language": language,
    }

    response = client.classify_text(request={"document": document})
    # Loop through classified categories returned from the API
    for category in response.categories:
        # Get the name of the category representing the document.
        # See the predefined taxonomy of categories:
        # https://cloud.google.com/natural-language/docs/categories
        print(f"Category name: {category.name}")
        # Get the confidence. Number representing how certain the classifier
        # is that this category represents the provided text.
        print(f"Confidence: {category.confidence}")

Additional languages

C#: Please follow the C# setup instructions on the client libraries page and then visit the Natural Language reference documentation for .NET.

PHP: Please follow the PHP setup instructions on the client libraries page and then visit the Natural Language reference documentation for PHP.

Ruby: Please follow the Ruby setup instructions on the client libraries page and then visit the Natural Language reference documentation for Ruby.