Delphi DLL Requires Chilkat v10.1.2+

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 DLL

var
success: Boolean;
socket: HCkSocket;
oauth2: HCkOAuth2;
url: PWideChar;
numMsWaited: Integer;
json: HCkJsonObject;
dtExpire: HCkDateTime;
fac: HCkFileAccess;

begin
success := False;

//  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 := CkSocket_Create();
//  Use your HTTP proxy server domain or IP address.
CkSocket_putHttpProxyHostname(socket,'myproxyserver.com');
//  Change this to the listening port of your HTTP proxy server (if necessary)
CkSocket_putHttpProxyPort(socket,808);
//  Specify login/password if needed.
CkSocket_putHttpProxyUsername(socket,'myProxyLogin');
CkSocket_putHttpProxyPassword(socket,'myProxyPassword');
CkSocket_putHttpProxyForHttp(socket,True);

oauth2 := CkOAuth2_Create();

//  We don't need to connect the socket beforehand.
//  Just tell oauth2 to use the socket which has the HTTP proxy properties.
success := CkOAuth2_UseConnection(oauth2,socket);

//  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.
CkOAuth2_putListenPort(oauth2,3017);

CkOAuth2_putAuthorizationEndpoint(oauth2,'https://login.microsoftonline.com/common/oauth2/v2.0/authorize');
CkOAuth2_putTokenEndpoint(oauth2,'https://login.microsoftonline.com/common/oauth2/v2.0/token');

//  Replace these with actual values.
CkOAuth2_putClientId(oauth2,'MICROSOFT-GRAPH-CLIENT-ID');
//  This is your app password:
CkOAuth2_putClientSecret(oauth2,'MICROSOFT-GRAPH-CLIENT-SECRET');

CkOAuth2_putCodeChallenge(oauth2,False);
//  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
CkOAuth2_putScope(oauth2,'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 := CkOAuth2__startAuth(oauth2);
if (CkOAuth2_getLastMethodSuccess(oauth2) <> True) then
  begin
    Memo1.Lines.Add(CkOAuth2__lastErrorText(oauth2));
    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 := CkOAuth2_LaunchBrowser(oauth2,url);
if (success = False) then
  begin
    Memo1.Lines.Add(CkOAuth2__lastErrorText(oauth2));
    Exit;
  end;

//  Wait for the user to approve or deny authorization in the browser.
numMsWaited := 0;
while (numMsWaited < 90000) and (CkOAuth2_getAuthFlowState(oauth2) < 3) do
  begin
    CkOAuth2_SleepMs(oauth2,100);
    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 (CkOAuth2_getAuthFlowState(oauth2) < 3) then
  begin
    CkOAuth2_Cancel(oauth2);
    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 (CkOAuth2_getAuthFlowState(oauth2) = 5) then
  begin
    Memo1.Lines.Add('OAuth2 failed to complete.');
    Memo1.Lines.Add(CkOAuth2__failureInfo(oauth2));
    Exit;
  end;

if (CkOAuth2_getAuthFlowState(oauth2) = 4) then
  begin
    Memo1.Lines.Add('OAuth2 authorization was denied.');
    Memo1.Lines.Add(CkOAuth2__accessTokenResponse(oauth2));
    Exit;
  end;

if (CkOAuth2_getAuthFlowState(oauth2) <> 3) then
  begin
    Memo1.Lines.Add('Unexpected AuthFlowState:' + IntToStr(CkOAuth2_getAuthFlowState(oauth2)));
    Exit;
  end;

Memo1.Lines.Add('OAuth2 authorization granted!');
Memo1.Lines.Add('Access Token = ' + CkOAuth2__accessToken(oauth2));

//  Get the full JSON response:
json := CkJsonObject_Create();
CkJsonObject_Load(json,CkOAuth2__accessTokenResponse(oauth2));
CkJsonObject_putEmitCompact(json,False);

//  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 (CkJsonObject_HasMember(json,'expires_on') <> True) then
  begin
    dtExpire := CkDateTime_Create();
    CkDateTime_SetFromCurrentSystemTime(dtExpire);
    CkDateTime_AddSeconds(dtExpire,CkJsonObject_IntOf(json,'expires_in'));
    CkJsonObject_AppendString(json,'expires_on',CkDateTime__getAsUnixTimeStr(dtExpire,False));
  end;

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

//  Save the JSON to a file for future requests.
fac := CkFileAccess_Create();
CkFileAccess_WriteEntireTextFile(fac,'qa_data/tokens/microsoftGraph.json',CkJsonObject__emit(json),'utf-8',False);

CkSocket_Dispose(socket);
CkOAuth2_Dispose(oauth2);
CkJsonObject_Dispose(json);
    CkDateTime_Dispose(dtExpire);
CkFileAccess_Dispose(fac);