Checking Whether an Object Exists

Function

This API is used to check whether an object exists. If the returned HTTP status code is 200, the object exists. If the returned HTTP status code is 404, the object or bucket does not exist.

Restrictions

• To check whether an object exists, you must be the bucket owner or have the required permission (obs:object:GetObject in IAM or GetObject in a bucket policy). For details, see Introduction to OBS Access Control, IAM Custom Policies, and Configuring an Object Policy.
• The mapping between OBS regions and endpoints must comply with what is listed in Regions and Endpoints.

Method

obsClient.doesObjectExist(final GetObjectMetadataRequest request)

Request Parameters

Responses

Sample Code

The following code shows how to check whether object objectname exists in bucket examplebucket.

import android.util.Log;

import com.obs.services.ObsClient;
import com.obs.services.exception.ObsException;
import com.obs.services.model.GetObjectMetadataRequest;

public class DoesObjectExistDemo {
    private static final String TAG = "DoesObjectExistDemo";

    public void doesObjectExist() {
       // Hard-coded or plaintext AK and SK are risky. For security purposes, encrypt your AK and SK and store them in the configuration file or environment variables. In this example, the AK and SK are stored in environment variables for identity authentication. Before running the code in this example, configure environment variables ACCESS_KEY_ID and SECRET_ACCESS_KEY_ID.
        // Obtain an AK/SK pair on the management console.
        String ak = System.getenv("ACCESS_KEY_ID");
        String sk = System.getenv("SECRET_ACCESS_KEY_ID");
        // Enter the endpoint corresponding to the bucket. CN North-Beijing4 is used here as an example. Replace it with the one currently in use.
        String endPoint = "https://your-endpoint";

        // Create an ObsClient instance.
        ObsClient obsClient = new ObsClient(ak, sk, endPoint);

        try {
            // Check whether the specified object exists.
            boolean exists = obsClient.doesObjectExist("examplebucket", "objectname");
            Log.i(TAG, exists ? "object exists!" : "object does not exist!");
            Log.i(TAG, "doesObjectExist successfully");

            // Alternatively, use the GetObjectMetadataRequest method.
            GetObjectMetadataRequest request = new GetObjectMetadataRequest("examplebucket", "objectname");
            boolean exists2 = obsClient.doesObjectExist(request);
            Log.i(TAG, exists2 ? "object exists!" : "object does not exist!");
        } catch (ObsException e) {
            Log.e(TAG, "doesObjectExist failed");
            // Request failed. Print the HTTP status code.
            Log.e(TAG, "HTTP Code:" + e.getResponseCode());
            // Request failed. Print the server-side error code.
            Log.e(TAG, "Error Code:" + e.getErrorCode());
            // Request failed. Print the error details.
            Log.e(TAG, "Error Message:" + e.getErrorMessage());
            // Request failed. Print the request ID.
            Log.e(TAG, "Request ID:" + e.getErrorRequestId());
            Log.e(TAG, "Host ID:" + e.getErrorHostId());
        } catch (Exception e) {
            Log.e(TAG, "doesObjectExist failed");
            // Print other error information.
            Log.e(TAG, e.getMessage());
        }
    }
}