(Delphi ActiveX) QuickBooks - Automatically Refresh Access Token with No User Interaction

Demonstrates how to automaticaly refresh an expired access token and retry the request after a 401 authorization error.

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
jsonToken: TChilkatJsonObject;
success: Integer;
rest: TChilkatRest;
bAutoReconnect: Integer;
sbAuth: TChilkatStringBuilder;
responseBody: WideString;
oauth2: TChilkatOAuth2;
sbJson: TChilkatStringBuilder;
json: TChilkatJsonObject;
dtime: TCkDateTime;
bLocalTime: Integer;
dt: IDtObj;

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

// Get our previously obtained OAuth2 access token, which should contain JSON like this:
// {
//   "expires_in": 3600,
//   "x_refresh_token_expires_in": 8726400,
//   "refresh_token": "L011546037639r ... 3vR2DrbOmg0Sdagw",
//   "access_token": "eyJlbmMiOiJBMTI4Q0 ... oETJEMbeggg",
//   "token_type": "bearer"
// }

jsonToken := TChilkatJsonObject.Create(Self);
success := jsonToken.LoadFile('qa_data/tokens/qb-access-token.json');

rest := TChilkatRest.Create(Self);

// Connect using TLS.
// A single REST object, once connected, can be used for many Quickbooks 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('sandbox-quickbooks.api.intuit.com',443,1,bAutoReconnect);
if (success <> 1) then
  begin
    Memo1.Lines.Add(rest.LastErrorText);
    Exit;
  end;

sbAuth := TChilkatStringBuilder.Create(Self);
sbAuth.Append('Bearer ');
sbAuth.Append(jsonToken.StringOf('access_token'));
rest.Authorization := sbAuth.GetAsString();

rest.AddHeader('Accept','application/json');
rest.AllowHeaderFolding := 0;

// The company ID is 123146096291789
// The employee ID is 58
responseBody := rest.FullRequestNoBody('GET','/v3/company/123146096291789/employee/58?minorversion=45');
if (rest.LastMethodSuccess <> 1) then
  begin
    Memo1.Lines.Add(rest.LastErrorText);
    Exit;
  end;

// If we get a 401 authorization error, then it's likely because the access token expired.
// We can automatically refresh it without interaction from the user.
if (rest.ResponseStatusCode = 401) then
  begin

    oauth2 := TChilkatOAuth2.Create(Self);

    oauth2.TokenEndpoint := 'https://oauth.platform.intuit.com/oauth2/v1/tokens/bearer';

    // Replace these with actual values.
    oauth2.ClientId := 'QUICKBOOKS-CLIENT-ID';
    oauth2.ClientSecret := 'QUICKBOOKS-CLIENT-SECRET';

    // Get the "refresh_token"
    oauth2.RefreshToken := jsonToken.StringOf('refresh_token');

    // Send the HTTP POST to refresh the access token..
    success := oauth2.RefreshAccessToken();
    if (success <> 1) then
      begin
        Memo1.Lines.Add(oauth2.LastErrorText);
        Exit;
      end;

    Memo1.Lines.Add('New access token: ' + oauth2.AccessToken);

    // Update the JSON with the new tokens.
    jsonToken.UpdateString('access_token',oauth2.AccessToken);

    // Save the new JSON access token response to a file.
    // The access + refresh tokens contained in this JSON will be needed for the next refresh.
    sbJson := TChilkatStringBuilder.Create(Self);
    jsonToken.EmitCompact := 0;
    jsonToken.EmitSb(sbJson.ControlInterface);
    sbJson.WriteFile('qa_data/tokens/qb-access-token.json','utf-8',0);

    Memo1.Lines.Add('OAuth2 token refreshed!');
    Memo1.Lines.Add('New Access Token = ' + oauth2.AccessToken);

    sbAuth.Clear();
    sbAuth.Append('Bearer ');
    sbAuth.Append(oauth2.AccessToken);
    rest.Authorization := sbAuth.GetAsString();

    // Now retry the request with the refreshed access token...
    responseBody := rest.FullRequestNoBody('GET','/v3/company/123146096291789/employee/58?minorversion=45');
    if (rest.LastMethodSuccess <> 1) then
      begin
        Memo1.Lines.Add(rest.LastErrorText);
        Exit;
      end;
  end;

// We should expect a 200 response if successful.
if (rest.ResponseStatusCode <> 200) then
  begin
    Memo1.Lines.Add('Request Header: ');
    Memo1.Lines.Add(rest.LastRequestHeader);
    Memo1.Lines.Add('----');
    Memo1.Lines.Add('Response StatusCode = ' + IntToStr(rest.ResponseStatusCode));
    Memo1.Lines.Add('Response StatusLine: ' + rest.ResponseStatusText);
    Memo1.Lines.Add('Response Header:');
    Memo1.Lines.Add(rest.ResponseHeader);
    Memo1.Lines.Add(responseBody);
    Exit;
  end;

// Load the JSON response into a JSON object for parsing.
// A sample JSON response is shown below.
json := TChilkatJsonObject.Create(Self);
json.Load(responseBody);

// These will be used for parsing date/time strings..
dtime := TCkDateTime.Create(Self);
bLocalTime := 1;

// Show the JSON.   
json.EmitCompact := 0;
Memo1.Lines.Add(json.Emit());

// Get some information from the JSON..
Memo1.Lines.Add('Name: ' + json.StringOf('Employee.DisplayName'));
Memo1.Lines.Add('Id: ' + json.StringOf('Employee.Id'));
Memo1.Lines.Add('City: ' + json.StringOf('Employee.PrimaryAddr.City'));
Memo1.Lines.Add('PostalCode: ' + json.StringOf('Employee.PrimaryAddr.PostalCode'));

// Load the CreateTime into a CkDateTime...
dtime.SetFromTimestamp(json.StringOf('Employee.MetaData.CreateTime'));
dt := dtime.GetDtObj(bLocalTime);
Memo1.Lines.Add(IntToStr(dt.Month) + '/' + IntToStr(dt.Day) + '/' + IntToStr(dt.Year) + '  ' + IntToStr(dt.Hour)
     + ':' + IntToStr(dt.Minute));

Memo1.Lines.Add('Success.');

// Use this online tool to generate parsing code from sample JSON: 
// Generate Parsing Code from JSON

// ------------------------------------------------------
// The JSON response looks like this:

// {
//   "Employee": {
//     "SSN": "XXX-XX-XXXX",
//     "PrimaryAddr": {
//       "Id": "116",
//       "Line1": "45 N. Elm Street",
//       "City": "Middlefield",
//       "CountrySubDivisionCode": "CA",
//       "PostalCode": "93242"
//     },
//     "BillableTime": false,
//     "domain": "QBO",
//     "sparse": false,
//     "Id": "98",
//     "SyncToken": "0",
//     "MetaData": {
//       "CreateTime": "2015-07-24T09:34:35-07:00",
//       "LastUpdatedTime": "2015-07-24T09:34:35-07:00"
//     },
//     "GivenName": "Bill",
//     "FamilyName": "Miller",
//     "DisplayName": "Bill Miller",
//     "PrintOnCheckName": "Bill Miller",
//     "Active": true,
//     "PrimaryPhone": {
//       "FreeFormNumber": "234-525-1234"
//     }
//   },
//   "time": "2015-07-24T09:35:54.805-07:00"
// 
end;