Delphi ActiveX

OAuth2 using an HTTP Proxy (for a Desktop Application)

See more OAuth2 Examples

Shows how to send OAuth2 communications through an HTTP proxy in a desktop application, using Microsoft Graph as an example. This method applies to all OAuth2 applications. Delphi ActiveX

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
success: Integer;
socket: TChilkatSocket;
oauth2: TChilkatOAuth2;
url: WideString;
numMsWaited: Integer;
json: TChilkatJsonObject;
dtExpire: TCkDateTime;
fac: TCkFileAccess;

begin
success := 0;

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

// To use an HTTP proxy with OAuth2, create a Chilkat socket object and specify the details.
socket := TChilkatSocket.Create(Self);
// Use your HTTP proxy server domain or IP address.
socket.HttpProxyHostname := 'myproxyserver.com';
// Change this to the listening port of your HTTP proxy server (if necessary)
socket.HttpProxyPort := 808;
// Specify login/password if needed.
socket.HttpProxyUsername := 'myProxyLogin';
socket.HttpProxyPassword := 'myProxyPassword';
socket.HttpProxyForHttp := 1;

oauth2 := TChilkatOAuth2.Create(Self);

// We don't need to connect the socket beforehand.
// Just tell oauth2 to use the socket which has the HTTP proxy properties.
success := oauth2.UseConnection(socket.ControlInterface);

// This should be the port in the localhost callback URL for your app.  
// The callback URL would look like "http://localhost:3017/" if the port number is 3017.
oauth2.ListenPort := 3017;

oauth2.AuthorizationEndpoint := 'https://login.microsoftonline.com/common/oauth2/v2.0/authorize';
oauth2.TokenEndpoint := 'https://login.microsoftonline.com/common/oauth2/v2.0/token';

// Replace these with actual values.
oauth2.ClientId := 'MICROSOFT-GRAPH-CLIENT-ID';
// This is your app password:
oauth2.ClientSecret := 'MICROSOFT-GRAPH-CLIENT-SECRET';

oauth2.CodeChallenge := 0;
// Provide a SPACE separated list of scopes.
// See https://developer.microsoft.com/en-us/graph/docs/authorization/permission_scopes 

// Important: To get a refresh token in the final response, you have to ask for "offline_access" scope
oauth2.Scope := 'openid profile offline_access user.readwrite mail.readwrite mail.send files.readwrite';

// Begin the OAuth2 Authorization code flow.  This returns a URL that should be loaded in a browser.
url := oauth2.StartAuth();
if (oauth2.LastMethodSuccess <> 1) then
  begin
    Memo1.Lines.Add(oauth2.LastErrorText);
    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 := oauth2.LaunchBrowser(url);
if (success = 0) then
  begin
    Memo1.Lines.Add(oauth2.LastErrorText);
    Exit;
  end;

// Wait for the user to approve or deny authorization in the browser.
numMsWaited := 0;
while (numMsWaited < 90000) and (oauth2.AuthFlowState < 3) do
  begin
    oauth2.SleepMs(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 (oauth2.AuthFlowState < 3) then
  begin
    oauth2.Cancel();
    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 (oauth2.AuthFlowState = 5) then
  begin
    Memo1.Lines.Add('OAuth2 failed to complete.');
    Memo1.Lines.Add(oauth2.FailureInfo);
    Exit;
  end;

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

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

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

// Get the full JSON response:
json := TChilkatJsonObject.Create(Self);
json.Load(oauth2.AccessTokenResponse);
json.EmitCompact := 0;

// The JSON response looks like this:

// {
//   "token_type": "Bearer",
//   "scope": "User.Read Mail.ReadWrite Mail.Send",
//   "expires_in": 3600,
//   "ext_expires_in": 0,
//   "access_token": "EwBAA8l6B...",
//   "refresh_token": "MCRMdbe...",
//   "id_token": "eyJ0eXA..."
// }

// If an "expires_on" member does not exist, then add the JSON member by
// getting the current system date/time and adding the "expires_in" seconds.
// This way we'll know when the token expires.
if (json.HasMember('expires_on') <> 1) then
  begin
    dtExpire := TCkDateTime.Create(Self);
    dtExpire.SetFromCurrentSystemTime();
    dtExpire.AddSeconds(json.IntOf('expires_in'));
    json.AppendString('expires_on',dtExpire.GetAsUnixTimeStr(0));
  end;

Memo1.Lines.Add(json.Emit());

// Save the JSON to a file for future requests.
fac := TCkFileAccess.Create(Self);
fac.WriteEntireTextFile('qa_data/tokens/microsoftGraph.json',json.Emit(),'utf-8',0);
end;