(Delphi DLL) Get Ebay OAuth2 in a Desktop App

See more eBay Examples

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

1. The authorization code grant flow (this example) (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 (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-authorization-code-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, OAuth2, StringBuilder;

...

procedure TForm1.Button1Click(Sender: TObject);
var
oauth2: HCkOAuth2;
url: PWideChar;
success: Boolean;
numMsWaited: Integer;
sbJson: HCkStringBuilder;

begin
// To further clarify, see OAuth 2.0 Authorization Flow

oauth2 := CkOAuth2_Create();

// See the Ebay documentation about Access token types
// Also see the Ebay documentation about authorization code grant flow

// Given that Ebay only allows redirect URLs using SSL/TLS, your applicaton must use an intermediate public web server (your own)
// to receive and forward the redirect to localhost.
// See Using Your Web Server as an Intermediary for OAuth2 Redirect to localhost
// 

// Ebay is unusual in that it wants the redirect URL indirectly.
// You need to provide the RuName (eBay Redirect URL name)
CkOAuth2_putAppCallbackUrl(oauth2,'Chilkat_Softwar-ChilkatS-Chilka-wxoumqdu');
CkOAuth2_putListenPort(oauth2,3017);

CkOAuth2_putAuthorizationEndpoint(oauth2,'https://auth.sandbox.ebay.com/oauth2/authorize');
CkOAuth2_putTokenEndpoint(oauth2,'https://api.sandbox.ebay.com/identity/v1/oauth2/token');

// Replace these with actual values.
CkOAuth2_putClientId(oauth2,'EBAY_CLIENT_ID');
CkOAuth2_putClientSecret(oauth2,'EBAY_CLIENT_SECRET');
CkOAuth2_putUseBasicAuth(oauth2,True);
CkOAuth2_putCodeChallenge(oauth2,False);

// 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

CkOAuth2_putScope(oauth2,'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');

// Begin the OAuth2 three-legged flow.  This returns a URL that should be loaded in a browser.
url := CkOAuth2__startAuth(oauth2);
if (CkOAuth2_getLastMethodSuccess(oauth2) <> True) then
  begin
    Memo1.Lines.Add(CkOAuth2__lastErrorText(oauth2));
    Exit;
  end;

Memo1.Lines.Add('url = ' + url);

// Launch the default browser on the system and navigate to the url.
// The LaunchBrowser method was added in Chilkat v10.1.2.
success := CkOAuth2_LaunchBrowser(oauth2,url);
if (success = False) then
  begin
    Memo1.Lines.Add(CkOAuth2__lastErrorText(oauth2));
    Exit;
  end;

// Wait for the user to approve or deny authorization in the browser.
numMsWaited := 0;
while (numMsWaited < 90000) and (CkOAuth2_getAuthFlowState(oauth2) < 3) do
  begin
    CkOAuth2_SleepMs(oauth2,100);
    numMsWaited := numMsWaited + 100;
  end;

// If the browser does not respond within the specified time, AuthFlowState will be:
// 
// 1: Waiting for Redirect – The OAuth2 background thread is waiting for the browser's redirect request.
// 2: Waiting for Final Response – The thread is awaiting the final access token response.
// In either case, cancel the background task initiated by StartAuth.

if (CkOAuth2_getAuthFlowState(oauth2) < 3) then
  begin
    CkOAuth2_Cancel(oauth2);
    Memo1.Lines.Add('No response from the browser!');
    Exit;
  end;

// Check AuthFlowState to determine if authorization was granted, denied, or failed:
// 
// 3: Success – OAuth2 flow completed, the background thread exited, and the successful response is in AccessTokenResponse.
// 4: Access Denied – OAuth2 flow completed, the background thread exited, and the error response is in AccessTokenResponse.
// 5: Failure – OAuth2 flow failed before completion, the background thread exited, and error details are in FailureInfo.

if (CkOAuth2_getAuthFlowState(oauth2) = 5) then
  begin
    Memo1.Lines.Add('OAuth2 failed to complete.');
    Memo1.Lines.Add(CkOAuth2__failureInfo(oauth2));
    Exit;
  end;

if (CkOAuth2_getAuthFlowState(oauth2) = 4) then
  begin
    Memo1.Lines.Add('OAuth2 authorization was denied.');
    Memo1.Lines.Add(CkOAuth2__accessTokenResponse(oauth2));
    Exit;
  end;

if (CkOAuth2_getAuthFlowState(oauth2) <> 3) then
  begin
    Memo1.Lines.Add('Unexpected AuthFlowState:' + IntToStr(CkOAuth2_getAuthFlowState(oauth2)));
    Exit;
  end;

Memo1.Lines.Add('OAuth2 authorization granted!');
Memo1.Lines.Add('Access Token = ' + CkOAuth2__accessToken(oauth2));

// Save the full JSON access token response to a file.
sbJson := CkStringBuilder_Create();
CkStringBuilder_Append(sbJson,CkOAuth2__accessTokenResponse(oauth2));
CkStringBuilder_WriteFile(sbJson,'qa_data/tokens/ebay-access-token.json','utf-8',False);

// The full JSON received looks like this:
// {
//   "access_token": "v^1.1#i^1#p^3#f^0#I^3#r^0#t^H4sIAAA... 3+fBIAAA==",
//   "expires_in": 7200,
//   "refresh_token": "v^1.1#i^1#f^0#p^3#r^1#I^3#t^Ul4xMF8wOkIxQzAzQjg1ND ... fMSNFXjEyODQ=",
//   "refresh_token_expires_in": 47304000,
//   "token_type": "User Access Token"
// }

CkOAuth2_Dispose(oauth2);
CkStringBuilder_Dispose(sbJson);

end;