(PowerBuilder) OAuth2 for a GMail using a JSON Service Account Key

Demonstrates how get an OAuth2 access token for GMail (Google Service Account) using a JSON private key.

After the access token is obtained, it may be used to send email. When the access token expires, a new access token needs to be obtained (using this same procedure).

Note: This is for OAuth2 using Google Service account keys.

Chilkat ActiveX Downloads ActiveX for 32-bit and 64-bit Windows

integer li_rc
oleobject loo_Fac
string ls_JsonKey
oleobject loo_GAuth
oleobject loo_TlsSock
integer li_Success
oleobject loo_Mailman
oleobject loo_Email

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

// First load the JSON key into a string.
loo_Fac = create oleobject
li_rc = loo_Fac.ConnectToNewObject("Chilkat_9_5_0.FileAccess")
if li_rc < 0 then
    destroy loo_Fac
    MessageBox("Error","Connecting to COM object failed")
    return
end if
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_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_9_5_0.AuthGoogle")

loo_GAuth.JsonKey = ls_JsonKey

// Choose a scope.
loo_GAuth.Scope = "https://mail.google.com/"

// 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 = ""

// 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_9_5_0.Socket")

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

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

// Now that we have the access token, it may be used to send email
// while it remains valid.  Once the access token expires, a new access token 
// should be obtained using the same code as above.

// -----------------------------------------------------------------------
loo_Mailman = create oleobject
li_rc = loo_Mailman.ConnectToNewObject("Chilkat_9_5_0.MailMan")

// Set the properties for the GMail SMTP server:
loo_Mailman.SmtpHost = "smtp.gmail.com"
loo_Mailman.SmtpPort = 587
loo_Mailman.StartTLS = 1

loo_Mailman.SmtpUsername = "YOUR_GOOGLE_APPS_USER_EMAIL_ADDRESS"
loo_Mailman.OAuth2AccessToken = loo_GAuth.AccessToken

// Create a new email object
loo_Email = create oleobject
li_rc = loo_Email.ConnectToNewObject("Chilkat_9_5_0.Email")

loo_Email.Subject = "This is a test"
loo_Email.Body = "This is a test"
loo_Email.From = "YOUR NAME <YOUR_GOOGLE_APPS_USER_EMAIL_ADDRESS>"
li_Success = loo_Email.AddTo("Chilkat Admin","admin@chilkatsoft.com")
// To add more recipients, call AddTo, AddCC, or AddBcc once per recipient.

// Call SendEmail to connect to the SMTP server and send.
// The connection (i.e. session) to the SMTP server remains
// open so that subsequent SendEmail calls may use the
// same connection.  
li_Success = loo_Mailman.SendEmail(loo_Email)
if li_Success <> 1 then
    Write-Debug loo_Mailman.LastErrorText
    destroy loo_Fac
    destroy loo_GAuth
    destroy loo_TlsSock
    destroy loo_Mailman
    destroy loo_Email
    return
end if

// You may close the connection here.  If the connection is kept open, 
// the next call to mailman.SendEmail will continue using the already-established connection
// (and automatically re-connect if needed).
li_Success = loo_Mailman.CloseSmtpConnection()
if li_Success <> 1 then
    Write-Debug "Connection to SMTP server not closed cleanly."
end if

Write-Debug "Email Sent via GMail using an OAuth2 Service Account Key."


destroy loo_Fac
destroy loo_GAuth
destroy loo_TlsSock
destroy loo_Mailman
destroy loo_Email