(Delphi DLL) Yahoo Mail OAuth2 Access Token for Desktop App

See more Yahoo Mail Examples

Demonstrates how to get a Yahoo Email OAuth2 access token from a desktop application or script.

This example requires a browser window to be displayed to allow the Yahoo account owner to authorize the access. The code for displaying the web browser is omitted. Suggestions for a few programming languages are provided in code comments. You'll need to add the code to display a web browser and navigate to the URL returned by the call to oauth2.StartAuth.

For more information, see https://developer.yahoo.com/oauth2/guide/

Chilkat for Delphi Downloads Chilkat non-ActiveX DLL for Delphi Chilkat ActiveX DLL for Delphi * The examples here use the non-ActiveX DLL.

uses
    Winapi.Windows, Winapi.Messages, System.SysUtils, System.Variants, System.Classes, Vcl.Graphics,
    Vcl.Controls, Vcl.Forms, Vcl.Dialogs, Vcl.StdCtrls, OAuth2, StringBuilder;

...

procedure TForm1.Button1Click(Sender: TObject);
var
oauth2: HCkOAuth2;
success: Boolean;
url: PWideChar;
numMsWaited: Integer;
sbJson: HCkStringBuilder;

begin
// First, you must define your app in Yahoo Developer (https://developer.yahoo.com/apps/) like this:

// 

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

oauth2 := CkOAuth2_Create();

// For a desktop app, you must provide a script on your web server to redirect to "http://localhost/<portNumber>"
// It can be written in C#, PHP, or whatever desired.  It must include the query string in the redirection.
// For example, in PHP your script would look like this:

// <?php
//   header( 'Location: http://localhost:3017?' . $_SERVER['QUERY_STRING'] );
// ?>

CkOAuth2_putAppCallbackUrl(oauth2,'https://yourwebserver.com/OAuth2.php');
CkOAuth2_putListenPort(oauth2,3017);

CkOAuth2_putAuthorizationEndpoint(oauth2,'https://api.login.yahoo.com/oauth2/request_auth');
CkOAuth2_putTokenEndpoint(oauth2,'https://api.login.yahoo.com/oauth2/get_token');

// Replace these with actual values.
CkOAuth2_putClientId(oauth2,'CLIENT_ID');
CkOAuth2_putClientSecret(oauth2,'CLIENT_SECRET');

// Do not send the "scope" query param for Yahoo OAuth2.
CkOAuth2_putUncommonOptions(oauth2,'NO_OAUTH2_SCOPE');

// Begin the OAuth2 three-legged 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);

// At this point, your application should load the URL in a browser.
// For example, 
// in C#: System.Diagnostics.Process.Start(url);
// in Java: Desktop.getDesktop().browse(new URI(url));
// in VBScript: Set wsh=WScript.CreateObject("WScript.Shell")
//              wsh.Run url
// in Xojo: ShowURL(url)  (see http://docs.xojo.com/index.php/ShowURL)
// in Dataflex: Runprogram Background "c:\Program Files\Internet Explorer\iexplore.exe" sUrl        
// The Google account owner would interactively accept or deny the authorization request.

// Add the code to load the url in a web browser here...
// Add the code to load the url in a web browser here...
// Add the code to load the url in a web browser here...
// System.Diagnostics.Process.Start(url);

// Now wait for the authorization.
// We'll wait for a max of 30 seconds.
numMsWaited := 0;
while (numMsWaited < 30000) and (CkOAuth2_getAuthFlowState(oauth2) < 3) do
  begin
    CkOAuth2_SleepMs(oauth2,100);
    numMsWaited := numMsWaited + 100;
  end;

// If there was no response from the browser within 30 seconds, then 
// the AuthFlowState will be equal to 1 or 2.
// 1: Waiting for Redirect. The OAuth2 background thread is waiting to receive the redirect HTTP request from the browser.
// 2: Waiting for Final Response. The OAuth2 background thread is waiting for the final access token response.
// In that case, cancel the background task started in the call to StartAuth.
if (CkOAuth2_getAuthFlowState(oauth2) < 3) then
  begin
    CkOAuth2_Cancel(oauth2);
    Memo1.Lines.Add('No response from the browser!');
    Exit;
  end;

// Check the AuthFlowState to see if authorization was granted, denied, or if some error occurred
// The possible AuthFlowState values are:
// 3: Completed with Success. The OAuth2 flow has completed, the background thread exited, and the successful JSON response is available in AccessTokenResponse property.
// 4: Completed with Access Denied. The OAuth2 flow has completed, the background thread exited, and the error JSON is available in AccessTokenResponse property.
// 5: Failed Prior to Completion. The OAuth2 flow failed to complete, the background thread exited, and the error information is available in the FailureInfo property.
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;

// Save the full JSON access token response to a file.
sbJson := CkStringBuilder_Create();
CkStringBuilder_Append(sbJson,CkOAuth2__accessTokenResponse(oauth2));
CkStringBuilder_WriteFile(sbJson,'qa_data/tokens/yahooMail.json','utf-8',False);

// The saved JSON response looks like this:

// {
//   "access_token": "kCVQdnOdul...LHucA--",
//   "refresh_token": "AIenVXETSo0jklFBVkPS8vVm8E.Ej9ToRG.xDbDYmZ65WIs5t6CZhDrD",
//   "expires_in": 3600,
//   "token_type": "bearer",
//   "xoauth_yahoo_guid": "HGDQCVF5JB4YDOWHITQJFBHCWA"
// }

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

CkOAuth2_Dispose(oauth2);
CkStringBuilder_Dispose(sbJson);

end;