(Delphi ActiveX) 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 for Delphi Downloads Chilkat ActiveX DLL for Delphi Chilkat non-ActiveX DLL for Delphi * The examples here use the ActiveX DLL.

uses
    Winapi.Windows, Winapi.Messages, System.SysUtils, System.Variants, System.Classes, Vcl.Graphics,
    Vcl.Controls, Vcl.Forms, Vcl.Dialogs, Vcl.StdCtrls, Chilkat_TLB;

...

procedure TForm1.Button1Click(Sender: TObject);
var
rest: TChilkatRest;
bAutoReconnect: Integer;
success: Integer;
responseStr: WideString;
json: TChilkatJsonObject;
dateTime: TCkDateTime;
bLocalTime: Integer;
dtNow: Integer;
sbResponse: TChilkatStringBuilder;
bEmitBom: Integer;

begin
// 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.

rest := TChilkatRest.Create(Self);

// 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.
bAutoReconnect := 1;
success := rest.Connect('api.sandbox.paypal.com',443,1,bAutoReconnect);
if (success <> 1) then
  begin
    Memo1.Lines.Add(rest.LastErrorText);
    Exit;
  end;

// 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"

rest.AddHeader('Accept','application/json');
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
rest.SetAuthBasic('PAYPAL_REST_API_CLIENT_ID','PAYPAL_REST_API_SECRET');

rest.AddQueryParam('grant_type','client_credentials');

responseStr := rest.FullRequestFormUrlEncoded('POST','/v1/oauth2/token');
if (rest.LastMethodSuccess <> 1) then
  begin
    Memo1.Lines.Add(rest.LastErrorText);
    Exit;
  end;

Memo1.Lines.Add(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
// 	}

json := TChilkatJsonObject.Create(Self);
json.Load(responseStr);
json.EmitCompact := 0;

// Check the response status code.  A 200 indicates success..
if (rest.ResponseStatusCode <> 200) then
  begin
    Memo1.Lines.Add(json.Emit());
    Memo1.Lines.Add('Failed.');
    Exit;
  end;

// 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).
dateTime := TCkDateTime.Create(Self);
bLocalTime := 0;
dtNow := dateTime.GetAsUnixTime(bLocalTime);
json.AppendInt('tokenCreateTimeUtc',dtNow);

// Examine the access token and save to a file.
Memo1.Lines.Add('Access Token: ' + json.StringOf('access_token'));
Memo1.Lines.Add('Full JSON Response:');
Memo1.Lines.Add(json.Emit());

sbResponse := TChilkatStringBuilder.Create(Self);
sbResponse.Append(json.Emit());
bEmitBom := 0;
sbResponse.WriteFile('qa_data/tokens/paypal.json','utf-8',bEmitBom);
end;