Recuperare i metadati di un oggetto

Recupera i metadati di un oggetto in un bucket Cloud Storage.

Per saperne di più

Per la documentazione dettagliata che include questo esempio di codice, vedi quanto segue:

Esempio di codice

C++

Per saperne di più, consulta la documentazione di riferimento dell'API Cloud Storage C++.

Per eseguire l'autenticazione in Cloud Storage, configura le Credenziali predefinite dell'applicazione. Per saperne di più, vedi Configurare l'autenticazione per le librerie client. 

namespace gcs = ::google::cloud::storage;
using ::google::cloud::StatusOr;
[](gcs::Client client, std::string const& bucket_name,
   std::string const& object_name) {
  StatusOr<gcs::ObjectMetadata> object_metadata =
      client.GetObjectMetadata(bucket_name, object_name);
  if (!object_metadata) throw std::move(object_metadata).status();

  std::cout << "The metadata for object " << object_metadata->name()
            << " in bucket " << object_metadata->bucket() << " is "
            << *object_metadata << "\n";
}

C#

Per saperne di più, consulta la documentazione di riferimento dell'API Cloud Storage C#.

Per eseguire l'autenticazione in Cloud Storage, configura le Credenziali predefinite dell'applicazione. Per saperne di più, vedi Configurare l'autenticazione per le librerie client. 


using Google.Cloud.Storage.V1;
using System;

public class GetMetadataSample
{
    public Google.Apis.Storage.v1.Data.Object GetMetadata(
        string bucketName = "your-unique-bucket-name",
        string objectName = "your-object-name")
    {
        var storage = StorageClient.Create();
        var storageObject = storage.GetObject(bucketName, objectName, new GetObjectOptions { Projection = Projection.Full });
        Console.WriteLine($"Bucket:\t{storageObject.Bucket}");
        Console.WriteLine($"CacheControl:\t{storageObject.CacheControl}");
        Console.WriteLine($"ComponentCount:\t{storageObject.ComponentCount}");
        Console.WriteLine($"ContentDisposition:\t{storageObject.ContentDisposition}");
        Console.WriteLine($"ContentEncoding:\t{storageObject.ContentEncoding}");
        Console.WriteLine($"ContentLanguage:\t{storageObject.ContentLanguage}");
        Console.WriteLine($"ContentType:\t{storageObject.ContentType}");
        Console.WriteLine($"Crc32c:\t{storageObject.Crc32c}");
        Console.WriteLine($"ETag:\t{storageObject.ETag}");
        Console.WriteLine($"Generation:\t{storageObject.Generation}");
        Console.WriteLine($"Id:\t{storageObject.Id}");
        Console.WriteLine($"Kind:\t{storageObject.Kind}");
        Console.WriteLine($"KmsKeyName:\t{storageObject.KmsKeyName}");
        Console.WriteLine($"Md5Hash:\t{storageObject.Md5Hash}");
        Console.WriteLine($"MediaLink:\t{storageObject.MediaLink}");
        Console.WriteLine($"Metageneration:\t{storageObject.Metageneration}");
        Console.WriteLine($"Name:\t{storageObject.Name}");
        Console.WriteLine($"Retention:\t{storageObject.Retention}");
        Console.WriteLine($"Size:\t{storageObject.Size}");
        Console.WriteLine($"StorageClass:\t{storageObject.StorageClass}");
        Console.WriteLine($"TimeCreated:\t{storageObject.TimeCreated}");
        Console.WriteLine($"Updated:\t{storageObject.Updated}");
        bool eventBasedHold = storageObject.EventBasedHold ?? false;
        Console.WriteLine("Event-based hold enabled? {0}", eventBasedHold);
        bool temporaryHold = storageObject.TemporaryHold ?? false;
        Console.WriteLine("Temporary hold enabled? {0}", temporaryHold);
        Console.WriteLine($"RetentionExpirationTime\t{storageObject.RetentionExpirationTime}");
        if (storageObject.Metadata != null)
        {
            Console.WriteLine("Metadata: ");
            foreach (var metadata in storageObject.Metadata)
            {
                Console.WriteLine($"{metadata.Key}:\t{metadata.Value}");
            }
        }
        Console.WriteLine($"CustomTime:\t{storageObject.CustomTime}");
        return storageObject;
    }
}

Go

Per saperne di più, consulta la documentazione di riferimento dell'API Cloud Storage Go.

Per eseguire l'autenticazione in Cloud Storage, configura le Credenziali predefinite dell'applicazione. Per saperne di più, vedi Configurare l'autenticazione per le librerie client. 

import (
	"context"
	"fmt"
	"io"
	"time"

	"cloud.google.com/go/storage"
)

// getMetadata prints all of the object attributes.
func getMetadata(w io.Writer, bucket, object string) (*storage.ObjectAttrs, error) {
	// bucket := "bucket-name"
	// object := "object-name"
	ctx := context.Background()
	client, err := storage.NewClient(ctx)
	if err != nil {
		return nil, fmt.Errorf("storage.NewClient: %w", err)
	}
	defer client.Close()

	ctx, cancel := context.WithTimeout(ctx, time.Second*10)
	defer cancel()

	o := client.Bucket(bucket).Object(object)
	attrs, err := o.Attrs(ctx)
	if err != nil {
		return nil, fmt.Errorf("Object(%q).Attrs: %w", object, err)
	}
	fmt.Fprintf(w, "Bucket: %v\n", attrs.Bucket)
	fmt.Fprintf(w, "CacheControl: %v\n", attrs.CacheControl)
	fmt.Fprintf(w, "ContentDisposition: %v\n", attrs.ContentDisposition)
	fmt.Fprintf(w, "ContentEncoding: %v\n", attrs.ContentEncoding)
	fmt.Fprintf(w, "ContentLanguage: %v\n", attrs.ContentLanguage)
	fmt.Fprintf(w, "ContentType: %v\n", attrs.ContentType)
	fmt.Fprintf(w, "Crc32c: %v\n", attrs.CRC32C)
	fmt.Fprintf(w, "Generation: %v\n", attrs.Generation)
	fmt.Fprintf(w, "KmsKeyName: %v\n", attrs.KMSKeyName)
	fmt.Fprintf(w, "Md5Hash: %v\n", attrs.MD5)
	fmt.Fprintf(w, "MediaLink: %v\n", attrs.MediaLink)
	fmt.Fprintf(w, "Metageneration: %v\n", attrs.Metageneration)
	fmt.Fprintf(w, "Name: %v\n", attrs.Name)
	fmt.Fprintf(w, "Size: %v\n", attrs.Size)
	fmt.Fprintf(w, "StorageClass: %v\n", attrs.StorageClass)
	fmt.Fprintf(w, "TimeCreated: %v\n", attrs.Created)
	fmt.Fprintf(w, "Updated: %v\n", attrs.Updated)
	fmt.Fprintf(w, "Event-based hold enabled? %t\n", attrs.EventBasedHold)
	fmt.Fprintf(w, "Temporary hold enabled? %t\n", attrs.TemporaryHold)
	fmt.Fprintf(w, "Retention expiration time %v\n", attrs.RetentionExpirationTime)
	fmt.Fprintf(w, "Custom time %v\n", attrs.CustomTime)
	fmt.Fprintf(w, "Retention: %+v\n", attrs.Retention)
	fmt.Fprintf(w, "\n\nMetadata\n")
	for key, value := range attrs.Metadata {
		fmt.Fprintf(w, "\t%v = %v\n", key, value)
	}
	return attrs, nil
}

Java

Per saperne di più, consulta la documentazione di riferimento dell'API Cloud Storage Java.

Per eseguire l'autenticazione in Cloud Storage, configura le Credenziali predefinite dell'applicazione. Per saperne di più, vedi Configurare l'autenticazione per le librerie client. 


import com.google.cloud.storage.Blob;
import com.google.cloud.storage.Storage;
import com.google.cloud.storage.StorageException;
import com.google.cloud.storage.StorageOptions;
import java.util.Date;
import java.util.Map;

public class GetObjectMetadata {
  public static void getObjectMetadata(String projectId, String bucketName, String blobName)
      throws StorageException {
    // The ID of your GCP project
    // String projectId = "your-project-id";

    // The ID of your GCS bucket
    // String bucketName = "your-unique-bucket-name";

    // The ID of your GCS object
    // String objectName = "your-object-name";

    Storage storage = StorageOptions.newBuilder().setProjectId(projectId).build().getService();

    // Select all fields
    // Fields can be selected individually e.g. Storage.BlobField.CACHE_CONTROL
    Blob blob =
        storage.get(bucketName, blobName, Storage.BlobGetOption.fields(Storage.BlobField.values()));

    // Print blob metadata
    System.out.println("Bucket: " + blob.getBucket());
    System.out.println("CacheControl: " + blob.getCacheControl());
    System.out.println("ComponentCount: " + blob.getComponentCount());
    System.out.println("ContentDisposition: " + blob.getContentDisposition());
    System.out.println("ContentEncoding: " + blob.getContentEncoding());
    System.out.println("ContentLanguage: " + blob.getContentLanguage());
    System.out.println("ContentType: " + blob.getContentType());
    System.out.println("CustomTime: " + blob.getCustomTime());
    System.out.println("Crc32c: " + blob.getCrc32c());
    System.out.println("Crc32cHexString: " + blob.getCrc32cToHexString());
    System.out.println("ETag: " + blob.getEtag());
    System.out.println("Generation: " + blob.getGeneration());
    System.out.println("Id: " + blob.getBlobId());
    System.out.println("KmsKeyName: " + blob.getKmsKeyName());
    System.out.println("Md5Hash: " + blob.getMd5());
    System.out.println("Md5HexString: " + blob.getMd5ToHexString());
    System.out.println("MediaLink: " + blob.getMediaLink());
    System.out.println("Metageneration: " + blob.getMetageneration());
    System.out.println("Name: " + blob.getName());
    System.out.println("Size: " + blob.getSize());
    System.out.println("StorageClass: " + blob.getStorageClass());
    System.out.println("TimeCreated: " + new Date(blob.getCreateTime()));
    System.out.println("Last Metadata Update: " + new Date(blob.getUpdateTime()));
    System.out.println("Object Retention Policy: " + blob.getRetention());
    Boolean temporaryHoldIsEnabled = (blob.getTemporaryHold() != null && blob.getTemporaryHold());
    System.out.println("temporaryHold: " + (temporaryHoldIsEnabled ? "enabled" : "disabled"));
    Boolean eventBasedHoldIsEnabled =
        (blob.getEventBasedHold() != null && blob.getEventBasedHold());
    System.out.println("eventBasedHold: " + (eventBasedHoldIsEnabled ? "enabled" : "disabled"));
    if (blob.getRetentionExpirationTime() != null) {
      System.out.println("retentionExpirationTime: " + new Date(blob.getRetentionExpirationTime()));
    }
    if (blob.getMetadata() != null) {
      System.out.println("\n\n\nUser metadata:");
      for (Map.Entry<String, String> userMetadata : blob.getMetadata().entrySet()) {
        System.out.println(userMetadata.getKey() + "=" + userMetadata.getValue());
      }
    }
  }
}

Node.js

Per saperne di più, consulta la documentazione di riferimento dell'API Cloud Storage Node.js.

Per eseguire l'autenticazione in Cloud Storage, configura le Credenziali predefinite dell'applicazione. Per saperne di più, vedi Configurare l'autenticazione per le librerie client. 

/**
 * TODO(developer): Uncomment the following lines before running the sample.
 */
// The ID of your GCS bucket
// const bucketName = 'your-unique-bucket-name';

// The ID of your GCS file
// const fileName = 'your-file-name';

// Imports the Google Cloud client library
const {Storage} = require('@google-cloud/storage');

// Creates a client
const storage = new Storage();

async function getMetadata() {
  // Gets the metadata for the file
  const [metadata] = await storage
    .bucket(bucketName)
    .file(fileName)
    .getMetadata();

  console.log(`Bucket: ${metadata.bucket}`);
  console.log(`CacheControl: ${metadata.cacheControl}`);
  console.log(`ComponentCount: ${metadata.componentCount}`);
  console.log(`ContentDisposition: ${metadata.contentDisposition}`);
  console.log(`ContentEncoding: ${metadata.contentEncoding}`);
  console.log(`ContentLanguage: ${metadata.contentLanguage}`);
  console.log(`ContentType: ${metadata.contentType}`);
  console.log(`CustomTime: ${metadata.customTime}`);
  console.log(`Crc32c: ${metadata.crc32c}`);
  console.log(`ETag: ${metadata.etag}`);
  console.log(`Generation: ${metadata.generation}`);
  console.log(`Id: ${metadata.id}`);
  console.log(`KmsKeyName: ${metadata.kmsKeyName}`);
  console.log(`Md5Hash: ${metadata.md5Hash}`);
  console.log(`MediaLink: ${metadata.mediaLink}`);
  console.log(`Metageneration: ${metadata.metageneration}`);
  console.log(`Name: ${metadata.name}`);
  console.log(`Size: ${metadata.size}`);
  console.log(`StorageClass: ${metadata.storageClass}`);
  console.log(`TimeCreated: ${new Date(metadata.timeCreated)}`);
  console.log(`Last Metadata Update: ${new Date(metadata.updated)}`);
  console.log(`TurboReplication: ${metadata.rpo}`);
  console.log(
    `temporaryHold: ${metadata.temporaryHold ? 'enabled' : 'disabled'}`
  );
  console.log(
    `eventBasedHold: ${metadata.eventBasedHold ? 'enabled' : 'disabled'}`
  );
  if (metadata.retentionExpirationTime) {
    console.log(
      `retentionExpirationTime: ${new Date(metadata.retentionExpirationTime)}`
    );
  }
  if (metadata.metadata) {
    console.log('\n\n\nUser metadata:');
    for (const key in metadata.metadata) {
      console.log(`${key}=${metadata.metadata[key]}`);
    }
  }
}

getMetadata().catch(console.error);

PHP

Per saperne di più, consulta la documentazione di riferimento dell'API Cloud Storage PHP.

Per eseguire l'autenticazione in Cloud Storage, configura le Credenziali predefinite dell'applicazione. Per saperne di più, vedi Configurare l'autenticazione per le librerie client. 

use Google\Cloud\Storage\StorageClient;

/**
 * List object metadata.
 *
 * @param string $bucketName The name of your Cloud Storage bucket.
 *        (e.g. 'my-bucket')
 * @param string $objectName The name of your Cloud Storage object.
 *        (e.g. 'my-object')
 */
function object_metadata(string $bucketName, string $objectName): void
{
    $storage = new StorageClient();
    $bucket = $storage->bucket($bucketName);
    $object = $bucket->object($objectName);
    $info = $object->info();
    if (isset($info['name'])) {
        printf('Blob: %s' . PHP_EOL, $info['name']);
    }
    if (isset($info['bucket'])) {
        printf('Bucket: %s' . PHP_EOL, $info['bucket']);
    }
    if (isset($info['storageClass'])) {
        printf('Storage class: %s' . PHP_EOL, $info['storageClass']);
    }
    if (isset($info['id'])) {
        printf('ID: %s' . PHP_EOL, $info['id']);
    }
    if (isset($info['size'])) {
        printf('Size: %s' . PHP_EOL, $info['size']);
    }
    if (isset($info['updated'])) {
        printf('Updated: %s' . PHP_EOL, $info['updated']);
    }
    if (isset($info['generation'])) {
        printf('Generation: %s' . PHP_EOL, $info['generation']);
    }
    if (isset($info['metageneration'])) {
        printf('Metageneration: %s' . PHP_EOL, $info['metageneration']);
    }
    if (isset($info['etag'])) {
        printf('Etag: %s' . PHP_EOL, $info['etag']);
    }
    if (isset($info['crc32c'])) {
        printf('Crc32c: %s' . PHP_EOL, $info['crc32c']);
    }
    if (isset($info['md5Hash'])) {
        printf('MD5 Hash: %s' . PHP_EOL, $info['md5Hash']);
    }
    if (isset($info['contentType'])) {
        printf('Content-type: %s' . PHP_EOL, $info['contentType']);
    }
    if (isset($info['temporaryHold'])) {
        printf('Temporary hold: %s' . PHP_EOL, ($info['temporaryHold'] ? 'enabled' : 'disabled'));
    }
    if (isset($info['eventBasedHold'])) {
        printf('Event-based hold: %s' . PHP_EOL, ($info['eventBasedHold'] ? 'enabled' : 'disabled'));
    }
    if (isset($info['retentionExpirationTime'])) {
        printf('Retention Expiration Time: %s' . PHP_EOL, $info['retentionExpirationTime']);
    }
    if (isset($info['retention'])) {
        printf('Retention mode: %s' . PHP_EOL, $info['retention']['mode']);
        printf('Retain until time is: %s' . PHP_EOL, $info['retention']['retainUntilTime']);
    }
    if (isset($info['customTime'])) {
        printf('Custom Time: %s' . PHP_EOL, $info['customTime']);
    }
    if (isset($info['metadata'])) {
        printf('Metadata: %s' . PHP_EOL, print_r($info['metadata'], true));
    }
}

Python

Per saperne di più, consulta la documentazione di riferimento dell'API Cloud Storage Python.

Per eseguire l'autenticazione in Cloud Storage, configura le Credenziali predefinite dell'applicazione. Per saperne di più, vedi Configurare l'autenticazione per le librerie client. 

from google.cloud import storage


def blob_metadata(bucket_name, blob_name):
    """Prints out a blob's metadata."""
    # bucket_name = 'your-bucket-name'
    # blob_name = 'your-object-name'

    storage_client = storage.Client()
    bucket = storage_client.bucket(bucket_name)

    # Retrieve a blob, and its metadata, from Google Cloud Storage.
    # Note that `get_blob` differs from `Bucket.blob`, which does not
    # make an HTTP request.
    blob = bucket.get_blob(blob_name)

    print(f"Blob: {blob.name}")
    print(f"Bucket: {blob.bucket.name}")
    print(f"Storage class: {blob.storage_class}")
    print(f"ID: {blob.id}")
    print(f"Size: {blob.size} bytes")
    print(f"Updated: {blob.updated}")
    print(f"Generation: {blob.generation}")
    print(f"Metageneration: {blob.metageneration}")
    print(f"Etag: {blob.etag}")
    print(f"Owner: {blob.owner}")
    print(f"Component count: {blob.component_count}")
    print(f"Crc32c: {blob.crc32c}")
    print(f"md5_hash: {blob.md5_hash}")
    print(f"Cache-control: {blob.cache_control}")
    print(f"Content-type: {blob.content_type}")
    print(f"Content-disposition: {blob.content_disposition}")
    print(f"Content-encoding: {blob.content_encoding}")
    print(f"Content-language: {blob.content_language}")
    print(f"Metadata: {blob.metadata}")
    print(f"Medialink: {blob.media_link}")
    print(f"Custom Time: {blob.custom_time}")
    print("Temporary hold: ", "enabled" if blob.temporary_hold else "disabled")
    print(
        "Event based hold: ",
        "enabled" if blob.event_based_hold else "disabled",
    )
    print(f"Retention mode: {blob.retention.mode}")
    print(f"Retention retain until time: {blob.retention.retain_until_time}")
    if blob.retention_expiration_time:
        print(
            f"retentionExpirationTime: {blob.retention_expiration_time}"
        )

Ruby

Per saperne di più, consulta la documentazione di riferimento dell'API Cloud Storage Ruby.

Per eseguire l'autenticazione in Cloud Storage, configura le Credenziali predefinite dell'applicazione. Per saperne di più, vedi Configurare l'autenticazione per le librerie client. 

def get_metadata bucket_name:, file_name:
  # The ID of your GCS bucket
  # bucket_name = "your-unique-bucket-name"

  # The ID of your GCS object
  # file_name = "your-file-name"

  require "google/cloud/storage"

  storage = Google::Cloud::Storage.new
  bucket  = storage.bucket bucket_name
  file    = bucket.file file_name

  puts "Name: #{file.name}"
  puts "Bucket: #{bucket.name}"
  puts "Storage class: #{bucket.storage_class}"
  puts "ID: #{file.id}"
  puts "Size: #{file.size} bytes"
  puts "Created: #{file.created_at}"
  puts "Updated: #{file.updated_at}"
  puts "Generation: #{file.generation}"
  puts "Metageneration: #{file.metageneration}"
  puts "Etag: #{file.etag}"
  puts "Owners: #{file.acl.owners.join ','}"
  puts "Crc32c: #{file.crc32c}"
  puts "md5_hash: #{file.md5}"
  puts "Cache-control: #{file.cache_control}"
  puts "Content-type: #{file.content_type}"
  puts "Content-disposition: #{file.content_disposition}"
  puts "Content-encoding: #{file.content_encoding}"
  puts "Content-language: #{file.content_language}"
  puts "KmsKeyName: #{file.kms_key}"
  puts "Event-based hold enabled?: #{file.event_based_hold?}"
  puts "Temporary hold enaled?: #{file.temporary_hold?}"
  puts "Retention Expiration: #{file.retention_expires_at}"
  puts "Custom Time: #{file.custom_time}"
  puts "Metadata:"
  file.metadata.each do |key, value|
    puts " - #{key} = #{value}"
  end
end

Passaggi successivi

Per cercare e filtrare gli esempi di codice per altri prodotti Google Cloud , consulta il browser degli esempi diGoogle Cloud .