Pascal (Lazarus/Delphi)

Get Ebay OAuth2 Token using Client Credentials Grant Flow

See more eBay Examples

Demonstrates how to get a Ebay OAuth2 access token using the client credentials grant flow.

There are two ways of "minting" an OAuth2 access token.

1. The authorization code grant flow (https://developer.ebay.com/api-docs/static/oauth-authorization-code-grant.html) This is where your app will be accessing another person's eBay account. It's an interactive process and requires the account owner's permission to get the access token the 1st time. After that, it can be refreshed indefinitely without user interaction.
2. The client credentials grant flow (this example) (https://developer.ebay.com/api-docs/static/oauth-client-credentials-grant.html) This is where you access your own eBay account. It's non-interactive and you can do it in automated services where user-interaction is not possible.

Pascal (Lazarus/Delphi)

program ChilkatDemo;

// Demonstrates using the Chilkat Pascal wrapper via the C bridge DLL.
// Builds as a console application under Lazarus (FPC) or Delphi.

{$IFDEF FPC}
  {$MODE DELPHI}
{$ENDIF}
{$APPTYPE CONSOLE}

uses
  {$IFDEF UNIX}
  cthreads,
  {$ENDIF}
  SysUtils,
  CkDllLoader,
  Chilkat.Http,
  Chilkat.HttpRequest,
  Chilkat.HttpResponse,
  Chilkat.StringBuilder,
  Chilkat.JsonObject;

// ---------------------------------------------------------------------------

procedure RunDemo;
var
  success: Boolean;
  http: THttp;
  req: THttpRequest;
  scope: string;
  resp: THttpResponse;
  sbResponseBody: TStringBuilder;
  jResp: TJsonObject;
  respStatusCode: Integer;
  access_token: string;
  expires_in: Integer;
  token_type: string;

begin
  success := False;

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

  http := THttp.Create;

  //  Implements the following CURL command:

  //  curl -X POST 'https://api.sandbox.ebay.com/identity/v1/oauth2/token' \
  //    -H 'Content-Type: application/x-www-form-urlencoded' \
  //    -H 'Authorization: Basic UkVTVFRlc3...wZi1hOGZhLTI4MmY=' \
  //    -d 'grant_type=client_credentials&scope=https%3A%2F%2Fapi.ebay.com%2Foauth%2Fapi_scope'

  //  Use the following online tool to generate HTTP code from a CURL command
  //  Convert a cURL Command to HTTP Source Code

  req := THttpRequest.Create;
  req.HttpVerb := 'POST';
  req.Path := '/identity/v1/oauth2/token';
  req.ContentType := 'application/x-www-form-urlencoded';
  req.AddParam('grant_type','client_credentials');

  //  The scope query param indicates the access to be provided by the token.
  //  Multiple scopes can be specified by separating each with a SPACE char.
  //  See the Ebay OAuth scopes documentation

  scope := 'https://api.ebay.com/oauth/api_scope https://api.ebay.com/oauth/api_scope/buy.order.readonly https://api.ebay.com/oauth/api_scope/buy.guest.order https://api.ebay.com/oauth/api_scope/sell.marketing.readonly https://api.ebay.com/oauth/api_scope/sell.marketing https://api.ebay.com/oauth/api_scope/sell.inventory.readonly https://api.ebay.com/oauth/api_scope/sell.inventory https://api.ebay.com/oauth/api_scope/sell.account.readonly https://api.ebay.com/oauth/api_scope/sell.account https://api.ebay.com/oauth/api_scope/sell.fulfillment.readonly https://api.ebay.com/oauth/api_scope/sell.fulfillment https://api.ebay.com/oauth/api_scope/sell.analytics.readonly https://api.ebay.com/oauth/api_scope/sell.marketplace.insights.readonly https://api.ebay.com/oauth/api_scope/commerce.catalog.readonly https://api.ebay.com/oauth/api_scope/buy.shopping.cart https://api.ebay.com/oauth/api_scope/buy.offer.auction';

  req.AddParam('scope',scope);

  //  Setting these properties causes the Authorization: Basic UkVTVFRlc3...wZi1hOGZhLTI4MmY=
  //  header to be added.
  http.Login := 'EBAY_CLIENT_ID';
  http.Password := 'EBAY_CLIENT_SECRET';
  http.BasicAuth := True;

  resp := THttpResponse.Create;
  success := http.HttpReq('https://api.sandbox.ebay.com/identity/v1/oauth2/token',req,resp);
  if (success = False) then
    begin
      WriteLn(http.LastErrorText);
      Exit;
    end;

  sbResponseBody := TStringBuilder.Create;
  resp.GetBodySb(sbResponseBody);
  jResp := TJsonObject.Create;
  jResp.LoadSb(sbResponseBody);
  jResp.EmitCompact := False;

  WriteLn('Response Body:');
  WriteLn(jResp.Emit());

  respStatusCode := resp.StatusCode;
  WriteLn('Response Status Code = ' + respStatusCode);
  if (respStatusCode >= 400) then
    begin
      WriteLn('Response Header:');
      WriteLn(resp.Header);
      WriteLn('Failed.');
      Exit;
    end;

  //  Sample JSON response:
  //  (Sample code for parsing the JSON response is shown below)

  //  {
  //    "access_token": "v^1.1#i^1#p^1#r^0#I^3#f^0#t^H4s ... wu67e3xAhskz4DAAA",
  //    "expires_in": 7200,
  //    "token_type": "Application Access Token"
  //  }

  //  Sample code for parsing the JSON response...
  //  Use the following online tool to generate parsing code from sample JSON:
  //  Generate Parsing Code from JSON

  access_token := jResp.StringOf('access_token');
  expires_in := jResp.IntOf('expires_in');
  token_type := jResp.StringOf('token_type');


  http.Free;
  req.Free;
  resp.Free;
  sbResponseBody.Free;
  jResp.Free;

end;

// ---------------------------------------------------------------------------

begin

  try
    RunDemo;
  except
    on E: Exception do
      WriteLn('Unhandled exception: ', E.ClassName, ': ', E.Message);
  end;

  WriteLn;
  {$IFDEF MSWINDOWS}
  WriteLn('Press Enter to exit...');
  ReadLn;
  {$ENDIF}
end.