Pascal (Lazarus/Delphi)

Get Google Account Info from OAuth2 Access Token

See more Google APIs Examples

In the Google OAuth2 authorization flow, an application can know the email address of the Google account used to authorize access by requesting and processing user information from the Google UserInfo endpoint after obtaining an access token. 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;
  http: THttp;
  sbResponseBody: TStringBuilder;
  jResp: TJsonObject;
  respStatusCode: Integer;
  v_sub: string;
  name: string;
  given_name: string;
  family_name: string;
  profile: string;
  picture: string;
  email: string;
  email_verified: Boolean;
  locale: string;

begin
  success := False;

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

  http := THttp.Create;

  //  Implements the following CURL command:

  //  curl -H "Authorization: Bearer YOUR_ACCESS_TOKEN" https://www.googleapis.com/oauth2/v3/userinfo

  //  Use the following online tool to generate HTTP code from a CURL command
  //  Convert a cURL Command to HTTP Source Code

  //  Adds the "Authorization: Bearer YOUR_ACCESS_TOKEN" header.
  http.AuthToken := 'YOUR_ACCESS_TOKEN';

  sbResponseBody := TStringBuilder.Create;
  success := http.QuickGetSb('https://www.googleapis.com/oauth2/v3/userinfo',sbResponseBody);
  if (success = False) then
    begin
      WriteLn(http.LastErrorText);
      Exit;
    end;

  jResp := TJsonObject.Create;
  jResp.LoadSb(sbResponseBody);
  jResp.EmitCompact := False;

  WriteLn('Response Body:');
  WriteLn(jResp.Emit());

  respStatusCode := http.LastStatus;
  WriteLn('Response Status Code = ' + respStatusCode);
  if (respStatusCode >= 400) then
    begin
      WriteLn('Response Header:');
      WriteLn(http.LastHeader);
      WriteLn('Failed.');
      Exit;
    end;

  //  Sample JSON response:
  //  (Sample code for parsing the JSON response is shown below)

  //  {
  //    "sub": "112233445678901234567",
  //    "name": "John Doe",
  //    "given_name": "John",
  //    "family_name": "Doe",
  //    "profile": "https://plus.google.com/112233445678901234567",
  //    "picture": "https://lh3.googleusercontent.com/a-/AOh14GiU-EXAMPLE",
  //    "email": "johndoe@example.com",
  //    "email_verified": true,
  //    "locale": "en"
  //  }

  //  Sample code for parsing the JSON response...
  //  Use the following online tool to generate parsing code from sample JSON:
  //  Generate Parsing Code from JSON

  v_sub := jResp.StringOf('sub');
  name := jResp.StringOf('name');
  given_name := jResp.StringOf('given_name');
  family_name := jResp.StringOf('family_name');
  profile := jResp.StringOf('profile');
  picture := jResp.StringOf('picture');
  email := jResp.StringOf('email');
  email_verified := jResp.BoolOf('email_verified');
  locale := jResp.StringOf('locale');


  http.Free;
  sbResponseBody.Free;
  jResp.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.