(Xojo Plugin) 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 Xojo Plugin Download Xojo Plugin for Windows, Linux, Mac OS X, and ARM, ARM64

// 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.

Dim rest As New 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.
Dim bAutoReconnect As Boolean
bAutoReconnect = True
Dim success As Boolean
success = rest.Connect("api.sandbox.paypal.com",443,True,bAutoReconnect)
If (success <> True) Then
    System.DebugLog(rest.LastErrorText)
    Return
End If

// 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"

success = rest.AddHeader("Accept","application/json")
success = rest.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
success = rest.SetAuthBasic("PAYPAL_REST_API_CLIENT_ID","PAYPAL_REST_API_SECRET")

success = rest.AddQueryParam("grant_type","client_credentials")

Dim responseStr As String
responseStr = rest.FullRequestFormUrlEncoded("POST","/v1/oauth2/token")
If (rest.LastMethodSuccess <> True) Then
    System.DebugLog(rest.LastErrorText)
    Return
End If

System.DebugLog(rest.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
// 	}

Dim json As New Chilkat.JsonObject
success = json.Load(responseStr)
json.EmitCompact = False

// Check the response status code.  A 200 indicates success..
If (rest.ResponseStatusCode <> 200) Then
    System.DebugLog(json.Emit())
    System.DebugLog("Failed.")
    Return
End If

// 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).
Dim dateTime As New Chilkat.CkDateTime
Dim bLocalTime As Boolean
bLocalTime = False
Dim dtNow As Int32
dtNow = dateTime.GetAsUnixTime(bLocalTime)
success = json.AppendInt("tokenCreateTimeUtc",dtNow)

// Examine the access token and save to a file.
System.DebugLog("Access Token: " + json.StringOf("access_token"))
System.DebugLog("Full JSON Response:")
System.DebugLog(json.Emit())

Dim sbResponse As New Chilkat.StringBuilder
success = sbResponse.Append(json.Emit())
Dim bEmitBom As Boolean
bEmitBom = False
success = sbResponse.WriteFile("qa_data/tokens/paypal.json","utf-8",bEmitBom)