(Delphi DLL) Auth0 Server-to-Server Access Token (Client Credentials flow)

Demonstrates how to obtain an Auth0 access token using client credentials (client_id and client_secret).

This is just a matter of duplicating this CURL command:

curl --request POST
  --url 'https://chilkat.auth0.com/oauth/token' \
  --header 'content-type: application/json' \
  --data '{"grant_type":"client_credentials","client_id": "xxxx","client_secret": "xxxx","audience": "https://api.example.com/geocoding/v1/"}'

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, HttpResponse, JsonObject;

...

procedure TForm1.Button1Click(Sender: TObject);
var
json: HCkJsonObject;
http: HCkHttp;
resp: HCkHttpResponse;
jsonResp: HCkJsonObject;

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

// We want to duplicate this curl command:
// 
// curl --request POST
//   --url 'https://chilkat.auth0.com/oauth/token' \
//   --header 'content-type: application/json' \
//   --data '{"grant_type":"client_credentials","client_id": "my_client_id","client_secret": "my_client_secret","audience": "https://api.example.com/geocoding/v1/"}'

// Build the JSON body of the request.
json := CkJsonObject_Create();
CkJsonObject_UpdateString(json,'grant_type','client_credentials');
CkJsonObject_UpdateString(json,'client_id','AUTH0-CLIENT-ID');
CkJsonObject_UpdateString(json,'client_secret','AUTH0-CLIENT-SECRET');
CkJsonObject_UpdateString(json,'audience','https://api.example.com/geocoding/v1/');

// IMPORTANT: You would use your own url.  You would not use "chilkat.auth0.com".  
// Instead you would use "your_name.auth0.com"
http := CkHttp_Create();
resp := CkHttp_PostJson3(http,'https://chilkat.auth0.com/oauth/token','application/json',json);
if (CkHttp_getLastMethodSuccess(http) <> True) then
  begin
    Memo1.Lines.Add(CkHttp__lastErrorText(http));
    Exit;
  end;

// A 200 response status code indicates success.  In the success case, the response body
// contains the JSON access token, such as: 
// {
//   "access_token": "eyJz93a...k4laUWw",
//   "token_type":"Bearer",
//   "expires_in":86400
// }
// 

Memo1.Lines.Add('response status code = ' + IntToStr(CkHttpResponse_getStatusCode(resp)));

// The repsonse is JSON if successful and also JSON for errors.
jsonResp := CkJsonObject_Create();
CkJsonObject_putEmitCompact(jsonResp,False);
CkJsonObject_Load(jsonResp,CkHttpResponse__bodyStr(resp));

if (CkHttpResponse_getStatusCode(resp) <> 200) then
  begin
    // The response body contains error information in JSON format.
    Memo1.Lines.Add(CkJsonObject__emit(jsonResp));
    CkHttpResponse_Dispose(resp);

    // An example of an error response:
    // 		{
    // 		  "error": "access_denied",
    // 		  "error_description": "Client is not authorized to access \"https://api.example.com/geocoding/v1/\". You might probably want to create a \"client-grant\" associated to this API. See: https://auth0.com/docs/api/v2#!/Client_Grants/post_client_grants"
    // 		}
    Exit;
  end;

Memo1.Lines.Add('Success!');
Memo1.Lines.Add(CkJsonObject__emit(jsonResp));

// A successful JSON response body looks like this:

// {
//   "access_token": "eyJz93a...k4laUWw",
//   "token_type":"Bearer",
//   "expires_in":86400
// }

CkHttpResponse_Dispose(resp);

CkJsonObject_Dispose(json);
CkHttp_Dispose(http);
CkJsonObject_Dispose(jsonResp);

end;