Android™

Get Google API Access Token using JSON Private Key using NIST Time Server Date/Time

Demonstrates how to get a Google API access token using a JSON service account private key, using the NIST time server date/time rather than the local system date/time. 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.

    //  First, let's get the current date/time from time-c.nist.gov
    CkSocket socket = new CkSocket();

    //  Connect to an NIST time server and read the current date/time
    int maxWaitMs = 8000;
    boolean useTls = false;
    success = socket.Connect("time-c.nist.gov",37,useTls,maxWaitMs);
    if (success != true) {
        Log.i(TAG, socket.lastErrorText());
        return;
        }

    //  The time server will send a big-endian 32-bit integer representing
    //  the number of seconds since since 00:00 (midnight) 1 January 1900 GMT.
    //  The ReceiveInt32 method will receive a 4-byte integer, but returns
    //  true or false to indicate success.  If successful, the integer
    //  is obtained via the ReceivedInt property.
    boolean bigEndian = true;
    success = socket.ReceiveInt32(bigEndian);
    if (success != true) {
        Log.i(TAG, socket.lastErrorText());
        return;
        }

    CkDateTime dt = new CkDateTime();
    dt.SetFromNtpTime(socket.get_ReceivedInt());

    //  Show the current local date/time
    boolean bLocalTime = true;
    Log.i(TAG, "Current local date/time: " + dt.getAsRfc822(bLocalTime));

    maxWaitMs = 10;
    socket.Close(maxWaitMs);

    //  ------------------------------------------------------------------------
    //  OK, we have the current date/time.  We'll use it to set the IAT property
    //  in the code below.

    //  First load the JSON key into a string.
    CkFileAccess fac = new CkFileAccess();
    String jsonKey = fac.readEntireTextFile("qa_data/googleApi/ChilkatTest-ab2ecd52ef98.json","utf-8");
    if (fac.get_LastMethodSuccess() != true) {
        Log.i(TAG, fac.lastErrorText());
        return;
        }

    //  A JSON private key should look like this:

    //  	{
    //  	  "type": "service_account",
    //  	  "project_id": "chilkattest-1350",
    //  	  "private_key_id": "fa2e36ee26986eab628b59868af8bec1d1c64c38",
    //  	  "private_key": "-----BEGIN PRIVATE KEY-----\nMIIEvgIjFa...28N64N2n1E4FYzBZjSdy\n-----END PRIVATE KEY-----\n",
    //  	  "client_email": "598922945226-00rb0ppfg0sndajo6bhvd4v17jtj2d3a@developer.gserviceaccount.com",
    //  	  "client_id": "598922945226-00rb0ppfg0snd9jo7bhvd4v17jtj2d3a.apps.googleusercontent.com",
    //  	  "auth_uri": "https://accounts.google.com/o/oauth2/auth",
    //  	  "token_uri": "https://accounts.google.com/o/oauth2/token",
    //  	  "auth_provider_x509_cert_url": "https://www.googleapis.com/oauth2/v1/certs",
    //  	  "client_x509_cert_url": "https://www.googleapis.com/robot/v1/metadata/x509/598922945226-00rb0ppfg0sndajo6bhvd4v17jtj2d3a%40developer.gserviceaccount.com"
    //  	}

    CkAuthGoogle gAuth = new CkAuthGoogle();
    gAuth.put_JsonKey(jsonKey);

    //  Choose a scope.
    gAuth.put_Scope("https://www.googleapis.com/auth/cloud-platform");

    //  Request an access token that is valid for this many seconds.
    gAuth.put_ExpireNumSeconds(3600);

    //  If the application is requesting delegated access:
    //  The email address of the user for which the application is requesting delegated access,
    //  then set the email address here. (Otherwise leave it empty.)
    gAuth.put_SubEmailAddress("");

    //  ------------------------------------------------------------------------
    //  Set the IAT using the date/time from the NIST time server.
    int unixTime = dt.GetAsUnixTime(false);
    Log.i(TAG, "unixTime = " + String.valueOf(unixTime));
    gAuth.put_Iat(unixTime);

    //  Connect to www.googleapis.com using TLS (TLS 1.2 is the default.)
    //  The Chilkat socket object is used so that the connection can be established
    //  through proxies or an SSH tunnel if desired.
    CkSocket tlsSock = new CkSocket();
    success = tlsSock.Connect("www.googleapis.com",443,true,5000);
    if (success != true) {
        Log.i(TAG, tlsSock.lastErrorText());
        return;
        }

    //  Send the request to obtain the access token.
    success = gAuth.ObtainAccessToken(tlsSock);
    if (success != true) {
        Log.i(TAG, gAuth.lastErrorText());
        return;
        }

    //  Examine the access token:
    Log.i(TAG, "Access Token: " + gAuth.accessToken());

  }

  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."
  }
}