Android: How to query a list of bucket name

Android: How to Query a List of Bucket Names

Introduction

This article guides you on how to query and retrieve a list of bucket names in your Android application using the Google Cloud Storage (GCS) API.

Prerequisites

* **Google Cloud Project:** Create a Google Cloud project at [https://console.cloud.google.com/](https://console.cloud.google.com/).
* **Enable GCS API:** Enable the Google Cloud Storage API for your project.
* **Service Account:** Create a service account with the necessary permissions to access your GCS buckets.
* **Credentials:** Download the service account key file as a JSON file.

Steps

1. **Add Dependencies:** Add the necessary Google Cloud client library dependencies to your `build.gradle` (Module: app) file:

“`
dependencies {
implementation ‘com.google.cloud:google-cloud-storage:2.9.0’
}
“`

2. **Authentication:** Authenticate your application using the service account credentials.

“`java
import com.google.auth.oauth2.GoogleCredentials;
import com.google.cloud.storage.Storage;
import com.google.cloud.storage.StorageOptions;

// Load the service account credentials from the JSON file.
GoogleCredentials credentials = GoogleCredentials.fromStream(new FileInputStream(“path/to/credentials.json”));

// Create a Storage client object using the credentials.
Storage storage = StorageOptions.newBuilder().setCredentials(credentials).build().getService();
“`

3. **Query Bucket Names:** Use the `list()` method of the `Storage` object to get a list of all buckets.

“`java
import com.google.cloud.storage.Bucket;

// Get a list of all buckets.
Iterable buckets = storage.list();

// Iterate over the list of buckets and print their names.
for (Bucket bucket : buckets) {
System.out.println(bucket.getName());
}
“`

Example

“`java
import com.google.auth.oauth2.GoogleCredentials;
import com.google.cloud.storage.Bucket;
import com.google.cloud.storage.Storage;
import com.google.cloud.storage.StorageOptions;

import java.io.FileInputStream;
import java.io.IOException;

public class ListBuckets {

public static void main(String[] args) throws IOException {
// Load the service account credentials from the JSON file.
GoogleCredentials credentials = GoogleCredentials.fromStream(new FileInputStream(“path/to/credentials.json”));

// Create a Storage client object using the credentials.
Storage storage = StorageOptions.newBuilder().setCredentials(credentials).build().getService();

// Get a list of all buckets.
Iterable buckets = storage.list();

// Iterate over the list of buckets and print their names.
for (Bucket bucket : buckets) {
System.out.println(bucket.getName());
}
}
}
“`

**Output:**

“`
my-bucket-1
my-bucket-2
…
“`

Additional Considerations

* **Pagination:** The `list()` method returns a paginated list of buckets. You can use the `iterateAll()` method to retrieve all buckets.
* **Prefix:** You can filter the list of buckets using a prefix string with the `list(String prefix)` method.
* **Permissions:** Ensure that your service account has the necessary permissions to list buckets.

Conclusion

By following the steps outlined in this article, you can successfully query a list of bucket names within your Android application using the Google Cloud Storage API. Remember to manage your service account credentials securely and to adhere to best practices for API usage.