(Visual FoxPro) Get Google Cloud SQL Access Token using Service Account JSON Private Key

Demonstrates how to get a Google Cloud SQL access token using a JSON service account private key. Obtaining an access token for a service account requires no user interaction (it does not require a browser, nor callback URI's, etc.).

When an access token expires, an application can be (and should be) designed to automatically fetch a new access token.

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

LOCAL loFac
LOCAL lcJsonKey
LOCAL loGAuth
LOCAL loTlsSock
LOCAL lnSuccess
LOCAL loSbToken

* 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.
* For versions of Chilkat < 10.0.0, use CreateObject('Chilkat_9_5_0.FileAccess')
loFac = CreateObject('Chilkat.FileAccess')
lcJsonKey = loFac.ReadEntireTextFile("qa_data/googleApi/ChilkatCloud-13a07a2e8b3f.json","utf-8")
IF (loFac.LastMethodSuccess <> 1) THEN
    ? loFac.LastErrorText
    RELEASE loFac
    CANCEL
ENDIF

* A JSON private key should look something 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"
* 	}

* For versions of Chilkat < 10.0.0, use CreateObject('Chilkat_9_5_0.AuthGoogle')
loGAuth = CreateObject('Chilkat.AuthGoogle')
loGAuth.JsonKey = lcJsonKey

* Choose a scope.
* Here's the OAuth 2.0 scope information for the Cloud SQL Admin API:
* https://www.googleapis.com/auth/sqlservice.admin 	(Read/write access to Cloud SQL.)
* https://www.googleapis.com/auth/cloud-platform 	(Instances.import and Instances.export need this additional scope.)
loGAuth.Scope = "https://www.googleapis.com/auth/sqlservice.admin"

* Request an access token that is valid for this many seconds.
loGAuth.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.)
loGAuth.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.
* For versions of Chilkat < 10.0.0, use CreateObject('Chilkat_9_5_0.Socket')
loTlsSock = CreateObject('Chilkat.Socket')
lnSuccess = loTlsSock.Connect("www.googleapis.com",443,1,5000)
IF (lnSuccess <> 1) THEN
    ? loTlsSock.LastErrorText
    RELEASE loFac
    RELEASE loGAuth
    RELEASE loTlsSock
    CANCEL
ENDIF

* Send the request to obtain the access token.
lnSuccess = loGAuth.ObtainAccessToken(loTlsSock)
IF (lnSuccess <> 1) THEN
    ? loGAuth.LastErrorText
    RELEASE loFac
    RELEASE loGAuth
    RELEASE loTlsSock
    CANCEL
ENDIF

* Examine the access token:
? "Access Token: " + loGAuth.AccessToken

* Access token looks like this:  ya29.c.Ko4Bwwe3nG5rUvoBmJwadi ... Br4Ogz0B6qLAjg

* We're going to save this access token to a file to be used
* by other examples.
* For versions of Chilkat < 10.0.0, use CreateObject('Chilkat_9_5_0.StringBuilder')
loSbToken = CreateObject('Chilkat.StringBuilder')
loSbToken.Append(loGAuth.AccessToken)
loSbToken.WriteFile("qa_data/tokens/google_cloud_sql_access_token.txt","utf-8",0)

RELEASE loFac
RELEASE loGAuth
RELEASE loTlsSock
RELEASE loSbToken