Pascal (Lazarus/Delphi)

Microsoft Graph -- List Users (Automatic OAuth2 Client Credentials)

See more Microsoft Graph Examples

Simplify OAuth2 client credentials by using Chilkat to automatically obtain the necessary access token. This example demonstrates the technique with the Microsoft Graph API's "List Users" request. 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.StringBuilder,
  Chilkat.JsonObject;

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

procedure RunDemo;
var
  success: Boolean;
  json: TJsonObject;
  http: THttp;
  sbResponse: TStringBuilder;
  odata_id: string;
  displayName: string;
  givenName: string;
  jobTitle: string;
  mail: string;
  mobilePhone: string;
  officeLocation: string;
  preferredLanguage: string;
  surname: string;
  userPrincipalName: string;
  id: string;
  j: Integer;
  count_j: Integer;
  odata_context: string;
  i: Integer;
  count_i: Integer;

begin
  success := False;

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

  //  Instead of directly sending a POST request to obtain an OAuth2 access token, 
  //  you can provide Chilkat with the necessary information to automatically fetch 
  //  the token using the Client Credentials flow. During the first HTTP request, 
  //  Chilkat will obtain the token if it doesn't have one yet, and then use it for 
  //  all subsequent requests. When the token is expired or about to expire, Chilkat 
  //  will automatically obtain a new one, eliminating the need for your application 
  //  to manage token expiration and renewal manually. This approach also reduces the 
  //  number of HTTP requests by utilizing valid tokens as long as possible.

  json := TJsonObject.Create;
  json.UpdateString('client_secret','CLIENT_SECRET');
  json.UpdateString('client_id','CLIENT_ID');
  json.UpdateString('token_endpoint','https://login.microsoftonline.com/TENANT_ID/oauth2/v2.0/token');
  json.UpdateString('scope','https://graph.microsoft.com/.default');

  http := THttp.Create;

  //  Provide the information to let Chilkat automatically obtain the access token.
  http.AuthToken := json.Emit();

  sbResponse := TStringBuilder.Create;

  success := http.QuickGetSb('https://graph.microsoft.com/v1.0/users',sbResponse);
  if (success <> True) then
    begin
      WriteLn(http.LastErrorText);
      Exit;
    end;

  json.LoadSb(sbResponse);
  json.EmitCompact := False;

  WriteLn('Status code = ' + http.LastStatus);
  if (http.LastStatus <> 200) then
    begin
      WriteLn(json.Emit());
      WriteLn('Failed.');
    end;

  WriteLn(json.Emit());

  //  Sample output
  //  {
  //    "@odata.context": "https://graph.microsoft.com/v1.0/$metadata#users",
  //    "value": [
  //      {
  //        "@odata.id": "https://graph.microsoft.com/v2/6d8ddd66-68d1-43b0-af5c-e31b4b7dd5cd/directoryObjects/fca490d8-5918-4201-8079-c5dcbeafcdc9/Microsoft.DirectoryServices.User",
  //        "businessPhones": [
  //        ],
  //        "displayName": "Joe Sample",
  //        "givenName": "Joe",
  //        "jobTitle": null,
  //        "mail": null,
  //        "mobilePhone": null,
  //        "officeLocation": null,
  //        "preferredLanguage": null,
  //        "surname": "Sample",
  //        "userPrincipalName": "admin_chilkatsoft.com#EXT#@adminchilkatsoft.onmicrosoft.com",
  //        "id": "fca490d8-5918-4201-8079-c5dcbeafcdc9"
  //      }
  //    ]
  //  }

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

  odata_context := json.StringOf('"@odata.context"');
  i := 0;
  count_i := json.SizeOfArray('value');
  while i < count_i do
    begin
      json.I := i;
      odata_id := json.StringOf('value[i]."@odata.id"');
      displayName := json.StringOf('value[i].displayName');
      givenName := json.StringOf('value[i].givenName');
      jobTitle := json.StringOf('value[i].jobTitle');
      mail := json.StringOf('value[i].mail');
      mobilePhone := json.StringOf('value[i].mobilePhone');
      officeLocation := json.StringOf('value[i].officeLocation');
      preferredLanguage := json.StringOf('value[i].preferredLanguage');
      surname := json.StringOf('value[i].surname');
      userPrincipalName := json.StringOf('value[i].userPrincipalName');
      id := json.StringOf('value[i].id');
      j := 0;
      count_j := json.SizeOfArray('value[i].businessPhones');
      while j < count_j do
        begin
          json.J := j;
          j := j + 1;
        end;

      i := i + 1;
    end;



  json.Free;
  http.Free;
  sbResponse.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.