C++

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. C++

#include <CkSocket.h>
#include <CkDateTime.h>
#include <CkFileAccess.h>
#include <CkAuthGoogle.h>

void ChilkatSample(void)
    {
    bool 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;

    //  Connect to an NIST time server and read the current date/time
    int maxWaitMs = 8000;
    bool useTls = false;
    success = socket.Connect("time-c.nist.gov",37,useTls,maxWaitMs);
    if (success != true) {
        std::cout << socket.lastErrorText() << "\r\n";
        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.
    bool bigEndian = true;
    success = socket.ReceiveInt32(bigEndian);
    if (success != true) {
        std::cout << socket.lastErrorText() << "\r\n";
        return;
    }

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

    //  Show the current local date/time
    bool bLocalTime = true;
    std::cout << "Current local date/time: " << dt.getAsRfc822(bLocalTime) << "\r\n";

    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;
    const char *jsonKey = fac.readEntireTextFile("qa_data/googleApi/ChilkatTest-ab2ecd52ef98.json","utf-8");
    if (fac.get_LastMethodSuccess() != true) {
        std::cout << fac.lastErrorText() << "\r\n";
        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;
    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);
    std::cout << "unixTime = " << unixTime << "\r\n";
    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;
    success = tlsSock.Connect("www.googleapis.com",443,true,5000);
    if (success != true) {
        std::cout << tlsSock.lastErrorText() << "\r\n";
        return;
    }

    //  Send the request to obtain the access token.
    success = gAuth.ObtainAccessToken(tlsSock);
    if (success != true) {
        std::cout << gAuth.lastErrorText() << "\r\n";
        return;
    }

    //  Examine the access token:
    std::cout << "Access Token: " << gAuth.accessToken() << "\r\n";
    }