Android™

Generate an AWS (S3) Pre-Signed URL to Download File

See more Amazon S3 (new) Examples

Demonstrates how to generate a pre-signed URL to download a file from the Amazon S3 service. 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 assumes the Chilkat API to have been previously unlocked.
    // See Global Unlock Sample for sample code.

    CkHttp http = new CkHttp();

    http.put_AwsAccessKey("AWS_ACCESS_KEY");
    http.put_AwsSecretKey("AWS_SECRET_KEY");

    // Make sure to set your AWS region correctly
    http.put_AwsRegion("us-east-1");

    String bucketName = "chilkat100";
    String objectName = "starfish/starfish.jpg";
    String localFilePath = "qa_output/starfish.jpg";
    String awsService = "s3";

    // The signed URL will be valid for this number of seconds:
    int numSecondsValid = 86400;

    // Choose between a URL beginning with "http://" or "https://"...
    boolean bUseHttps = false;

    // Generate the pre-signed URL
    String preSignedUrl = http.s3_GenPresignedUrl("GET",bUseHttps,bucketName,objectName,numSecondsValid,awsService);
    if (http.get_LastMethodSuccess() == false) {
        Log.i(TAG, http.lastErrorText());
        return;
        }

    // The following URL can be copy-and-pasted into a browser..
    Log.i(TAG, "Pre-Signed AWS S3 URL: " + preSignedUrl);

    // Here's an example of a pre-signed URL. 
    // This URL will only work within 1 day (86400 seconds) after the time this example was published.
    // 
    //     http://chilkat100.s3.amazonaws.com/starfish/starfish.jpg?X-Amz-Algorithm=AWS4-HMAC-SHA256&X-Amz-Credential=16QXXDGY83AJJR6RVQ02%2F20170111%2Fus-west-2%2Fs3%2Faws4_request&X-Amz-Date=20170111T161959Z&X-Amz-Expires=86400&X-Amz-SignedHeaders=host&X-Amz-Signature=72bf4fd9a15d7bbcdd313a3318d937a778905f62a3fbff9b789d8dc28acd9232

    // Now try to do an HTTP Download using the signed URL.
    success = http.Download(preSignedUrl,"c:/temp/qa_output/starfish.jpg");
    if (success == false) {
        Log.i(TAG, http.lastErrorText());
        return;
        }

    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."
  }
}