(Delphi DLL) 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.

For more information, see https://developer.ebay.com/api-docs/static/oauth-client-credentials-grant.html

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

uses
    Winapi.Windows, Winapi.Messages, System.SysUtils, System.Variants, System.Classes, Vcl.Graphics,
    Vcl.Controls, Vcl.Forms, Vcl.Dialogs, Vcl.StdCtrls, Http, HttpRequest, HttpResponse, StringBuilder, JsonObject;

...

procedure TForm1.Button1Click(Sender: TObject);
var
http: HCkHttp;
success: Boolean;
req: HCkHttpRequest;
scope: PWideChar;
resp: HCkHttpResponse;
sbResponseBody: HCkStringBuilder;
jResp: HCkJsonObject;
respStatusCode: Integer;
access_token: PWideChar;
expires_in: Integer;
token_type: PWideChar;

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

http := CkHttp_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 := CkHttpRequest_Create();
CkHttpRequest_putHttpVerb(req,'POST');
CkHttpRequest_putPath(req,'/identity/v1/oauth2/token');
CkHttpRequest_putContentType(req,'application/x-www-form-urlencoded');
CkHttpRequest_AddParam(req,'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';

CkHttpRequest_AddParam(req,'scope',scope);

// Setting these properties causes the Authorization: Basic UkVTVFRlc3...wZi1hOGZhLTI4MmY=
// header to be added.
CkHttp_putLogin(http,'EBAY_CLIENT_ID');
CkHttp_putPassword(http,'EBAY_CLIENT_SECRET');
CkHttp_putBasicAuth(http,True);

resp := CkHttp_PostUrlEncoded(http,'https://api.sandbox.ebay.com/identity/v1/oauth2/token',req);
if (CkHttp_getLastMethodSuccess(http) = False) then
  begin
    Memo1.Lines.Add(CkHttp__lastErrorText(http));
    Exit;
  end;

sbResponseBody := CkStringBuilder_Create();
CkHttpResponse_GetBodySb(resp,sbResponseBody);
jResp := CkJsonObject_Create();
CkJsonObject_LoadSb(jResp,sbResponseBody);
CkJsonObject_putEmitCompact(jResp,False);

Memo1.Lines.Add('Response Body:');
Memo1.Lines.Add(CkJsonObject__emit(jResp));

respStatusCode := CkHttpResponse_getStatusCode(resp);
Memo1.Lines.Add('Response Status Code = ' + IntToStr(respStatusCode));
if (respStatusCode >= 400) then
  begin
    Memo1.Lines.Add('Response Header:');
    Memo1.Lines.Add(CkHttpResponse__header(resp));
    Memo1.Lines.Add('Failed.');
    CkHttpResponse_Dispose(resp);
    Exit;
  end;
CkHttpResponse_Dispose(resp);

// 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 := CkJsonObject__stringOf(jResp,'access_token');
expires_in := CkJsonObject_IntOf(jResp,'expires_in');
token_type := CkJsonObject__stringOf(jResp,'token_type');

CkHttp_Dispose(http);
CkHttpRequest_Dispose(req);
CkStringBuilder_Dispose(sbResponseBody);
CkJsonObject_Dispose(jResp);

end;