Android™

Azure Blob - Get Tags (Check if Blob Exists)

See more Azure Cloud Storage Examples

Gets the user-defined tags for a specified blob. This can also be used as a way to check to see if a blob exists. Android™

// Important: Don't forget to include the call to System.loadLibrary
// as shown at the bottom of this code sample.
package com.test;

import android.app.Activity;
import com.chilkatsoft.*;

import android.widget.TextView;
import android.os.Bundle;

public class SimpleActivity extends Activity {

  private static final String TAG = "Chilkat";

  // Called when the activity is first created.
  @Override
  public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);

    boolean success = false;

    //  This example requires the Chilkat API to have been previously unlocked.
    //  See Global Unlock Sample for sample code.

    CkRest rest = new CkRest();

    //  Connect to the Azure Storage Blob Service
    boolean bTls = true;
    int port = 443;
    boolean bAutoReconnect = true;
    //  In this example, the storage account name is "chilkat".
    success = rest.Connect("chilkat.blob.core.windows.net",port,bTls,bAutoReconnect);
    if (success != true) {
        Log.i(TAG, rest.lastErrorText());
        return;
        }

    //  Provide Azure Cloud credentials for the REST call.
    CkAuthAzureStorage azAuth = new CkAuthAzureStorage();
    azAuth.put_AccessKey("AZURE_ACCESS_KEY");
    //  The account name used here should match the 1st part of the domain passed in the call to Connect (above).
    azAuth.put_Account("chilkat");
    azAuth.put_Scheme("SharedKey");
    azAuth.put_Service("Blob");
    //  This causes the "x-ms-version: 2021-08-06" header to be automatically added.
    azAuth.put_XMsVersion("2021-08-06");
    success = rest.SetAuthAzureStorage(azAuth);

    //  Note: The application does not need to explicitly set the following
    //  headers: Content-Length, x-ms-date, Authorization.  These headers
    //  are automatically set by Chilkat.

    //  The Azure blob container is "test", the file is "helloWorld.txt"
    //  Add "?comp=tags" to get the user-defined tags instead of the actual blob content.
    CkStringBuilder sb = new CkStringBuilder();
    success = rest.FullRequestNoBodySb("GET","/test/helloWorldajdfadf.txt?comp=tags",sb);
    if (success == false) {
        //  Examine the request/response to see what happened.
        Log.i(TAG, "response status code = " + String.valueOf(rest.get_ResponseStatusCode()));
        Log.i(TAG, "response status text = " + rest.responseStatusText());
        Log.i(TAG, "response header: " + rest.responseHeader());
        Log.i(TAG, "---");
        Log.i(TAG, "LastRequestStartLine: " + rest.lastRequestStartLine());
        Log.i(TAG, "LastRequestHeader: " + rest.lastRequestHeader());
        return;
        }

    //  A typical blob with no tags will return this:

    //  <?xml version="1.0" encoding="utf-8"?>
    //  <Tags><TagSet/></Tags>

    //  If the blob does not exist, you get this:

    //  <?xml version="1.0" encoding="utf-8"?>
    //  <Error>
    //      <Code>BlobNotFound</Code>
    //      <Message>The specified blob does not exist.
    //  	RequestId:fcfefdd9-301e-001a-2135-3a23d2000000
    //  	Time:2023-02-06T14:17:00.7805577Z
    //      </Message>
    //  </Error>

    Log.i(TAG, sb.getAsString());

    //  To see if we got Tags or an Error, then examine the XML.
    CkXml xml = new CkXml();
    xml.LoadSb(sb,true);

    //  Examine the tag..
    if (xml.TagEquals("Tags") == true) {
        Log.i(TAG, "Blob exists!");
        }
    else {

        if (xml.ChildContentMatches("Code","BlobNotFound",true) == true) {
            Log.i(TAG, "Blob does not exist.");
            }
        else {
            Log.i(TAG, "Some other error...");
            }

        }

    Log.i(TAG, "Success.");

  }

  static {
      System.loadLibrary("chilkat");

      // Note: If the incorrect library name is passed to System.loadLibrary,
      // then you will see the following error message at application startup:
      //"The application <your-application-name> has stopped unexpectedly. Please try again."
  }
}