(Visual FoxPro) PayPal -- Get an OAuth 2.0 Access Token

Demonstrates how to send a request to get a PayPal OAuth2 access token. Sends an HTTP request equivalent to the following:

curl https://api.sandbox.paypal.com/v1/oauth2/token \
  -H "Accept: application/json" \
  -H "Accept-Language: en_US" \
  -u "Client-Id:Secret" \
  -d "grant_type=client_credentials"

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

LOCAL loRest
LOCAL lnBAutoReconnect
LOCAL lnSuccess
LOCAL lcResponseStr
LOCAL loJson
LOCAL loDateTime
LOCAL lnBLocalTime
LOCAL lnDtNow
LOCAL loSbResponse
LOCAL lnBEmitBom

* Note: Requires Chilkat v9.5.0.64 or greater.

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

* For versions of Chilkat < 10.0.0, use CreateObject('Chilkat_9_5_0.Rest')
loRest = CreateObject('Chilkat.Rest')

* Make the initial connection.
* A single REST object, once connected, can be used for many PayPal REST API calls.
* The auto-reconnect indicates that if the already-established HTTPS connection is closed,
* then it will be automatically re-established as needed.
lnBAutoReconnect = 1
lnSuccess = loRest.Connect("api.sandbox.paypal.com",443,1,lnBAutoReconnect)
IF (lnSuccess <> 1) THEN
    ? loRest.LastErrorText
    RELEASE loRest
    CANCEL
ENDIF

* Duplicate this request:

* 	curl https://api.sandbox.paypal.com/v1/oauth2/token \
* 	  -H "Accept: application/json" \
* 	  -H "Accept-Language: en_US" \
* 	  -u "Client-Id:Secret" \
* 	  -d "grant_type=client_credentials"

loRest.AddHeader("Accept","application/json")
loRest.AddHeader("Accept-Language","en_US")

* For additional help on where to find  your client ID and API secret, see PayPal Client_ID and API_Secret
loRest.SetAuthBasic("PAYPAL_REST_API_CLIENT_ID","PAYPAL_REST_API_SECRET")

loRest.AddQueryParam("grant_type","client_credentials")

lcResponseStr = loRest.FullRequestFormUrlEncoded("POST","/v1/oauth2/token")
IF (loRest.LastMethodSuccess <> 1) THEN
    ? loRest.LastErrorText
    RELEASE loRest
    CANCEL
ENDIF

? loRest.LastRequestHeader

* A sample response:

* 	{
* 	  "scope": "https://api.paypal.com/v1/payments/.* https://api.paypal.com/v1/vault/credit-card https://api.paypal.com/v1/vault/credit-card/.*",
* 	  "access_token": "EEwJ6tF9x5WCIZDYzyZGaz6Khbw7raYRIBV_WxVvgmsG",
* 	  "token_type": "Bearer",
* 	  "app_id": "APP-6XR95014BA15863X",
* 	  "expires_in": 28800
* 	}

* For versions of Chilkat < 10.0.0, use CreateObject('Chilkat_9_5_0.JsonObject')
loJson = CreateObject('Chilkat.JsonObject')
loJson.Load(lcResponseStr)
loJson.EmitCompact = 0

* Check the response status code.  A 200 indicates success..
IF (loRest.ResponseStatusCode <> 200) THEN
    ? loJson.Emit()
    ? "Failed."
    RELEASE loRest
    RELEASE loJson
    CANCEL
ENDIF

* Given that the access token expires in approx 8 hours,
* let's record the date/time this token was created.
* This will allow us to know beforehand if the token
* is expired (and we can then fetch a new token).
* For versions of Chilkat < 10.0.0, use CreateObject('Chilkat_9_5_0.CkDateTime')
loDateTime = CreateObject('Chilkat.CkDateTime')
lnBLocalTime = 0
lnDtNow = loDateTime.GetAsUnixTime(lnBLocalTime)
loJson.AppendInt("tokenCreateTimeUtc",lnDtNow)

* Examine the access token and save to a file.
? "Access Token: " + loJson.StringOf("access_token")
? "Full JSON Response:"
? loJson.Emit()

* For versions of Chilkat < 10.0.0, use CreateObject('Chilkat_9_5_0.StringBuilder')
loSbResponse = CreateObject('Chilkat.StringBuilder')
loSbResponse.Append(loJson.Emit())
lnBEmitBom = 0
loSbResponse.WriteFile("qa_data/tokens/paypal.json","utf-8",lnBEmitBom)

RELEASE loRest
RELEASE loJson
RELEASE loDateTime
RELEASE loSbResponse