PowerBuilder

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. PowerBuilder

integer li_rc
long li_Success
oleobject loo_Socket
long li_MaxWaitMs
long li_UseTls
long li_BigEndian
oleobject loo_Dt
long li_BLocalTime
oleobject loo_Fac
string ls_JsonKey
oleobject loo_GAuth
long li_UnixTime
oleobject loo_TlsSock

li_Success = 0

//  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
loo_Socket = create oleobject
li_rc = loo_Socket.ConnectToNewObject("Chilkat.Socket")
if li_rc < 0 then
    destroy loo_Socket
    MessageBox("Error","Connecting to COM object failed")
    return
end if

//  Connect to an NIST time server and read the current date/time
li_MaxWaitMs = 8000
li_UseTls = 0
li_Success = loo_Socket.Connect("time-c.nist.gov",37,li_UseTls,li_MaxWaitMs)
if li_Success <> 1 then
    Write-Debug loo_Socket.LastErrorText
    destroy loo_Socket
    return
end if

//  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
//  1 or 0 to indicate success.  If successful, the integer
//  is obtained via the ReceivedInt property.
li_BigEndian = 1
li_Success = loo_Socket.ReceiveInt32(li_BigEndian)
if li_Success <> 1 then
    Write-Debug loo_Socket.LastErrorText
    destroy loo_Socket
    return
end if

loo_Dt = create oleobject
li_rc = loo_Dt.ConnectToNewObject("Chilkat.CkDateTime")

loo_Dt.SetFromNtpTime(loo_Socket.ReceivedInt)

//  Show the current local date/time
li_BLocalTime = 1
Write-Debug "Current local date/time: " + loo_Dt.GetAsRfc822(li_BLocalTime)

li_MaxWaitMs = 10
loo_Socket.Close(li_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.
loo_Fac = create oleobject
li_rc = loo_Fac.ConnectToNewObject("Chilkat.FileAccess")

ls_JsonKey = loo_Fac.ReadEntireTextFile("qa_data/googleApi/ChilkatTest-ab2ecd52ef98.json","utf-8")
if loo_Fac.LastMethodSuccess <> 1 then
    Write-Debug loo_Fac.LastErrorText
    destroy loo_Socket
    destroy loo_Dt
    destroy loo_Fac
    return
end if

//  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"
//  	}

loo_GAuth = create oleobject
li_rc = loo_GAuth.ConnectToNewObject("Chilkat.AuthGoogle")

loo_GAuth.JsonKey = ls_JsonKey

//  Choose a scope.
loo_GAuth.Scope = "https://www.googleapis.com/auth/cloud-platform"

//  Request an access token that is valid for this many seconds.
loo_GAuth.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.)
loo_GAuth.SubEmailAddress = ""

//  ------------------------------------------------------------------------
//  Set the IAT using the date/time from the NIST time server.
li_UnixTime = loo_Dt.GetAsUnixTime(0)
Write-Debug "unixTime = " + string(li_UnixTime)
loo_GAuth.Iat = li_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.
loo_TlsSock = create oleobject
li_rc = loo_TlsSock.ConnectToNewObject("Chilkat.Socket")

li_Success = loo_TlsSock.Connect("www.googleapis.com",443,1,5000)
if li_Success <> 1 then
    Write-Debug loo_TlsSock.LastErrorText
    destroy loo_Socket
    destroy loo_Dt
    destroy loo_Fac
    destroy loo_GAuth
    destroy loo_TlsSock
    return
end if

//  Send the request to obtain the access token.
li_Success = loo_GAuth.ObtainAccessToken(loo_TlsSock)
if li_Success <> 1 then
    Write-Debug loo_GAuth.LastErrorText
    destroy loo_Socket
    destroy loo_Dt
    destroy loo_Fac
    destroy loo_GAuth
    destroy loo_TlsSock
    return
end if

//  Examine the access token:
Write-Debug "Access Token: " + loo_GAuth.AccessToken


destroy loo_Socket
destroy loo_Dt
destroy loo_Fac
destroy loo_GAuth
destroy loo_TlsSock