Using Microsoft/Office 365 OAUTH + EWS and Ms Graph API

Microsoft Office365 EWS and Ms Graph API servers have been extended to support authorization via the industry-standard OAuth 2.0 protocol. Using OAUTH protocol, user can do authentication by Microsoft Web OAuth instead of inputting user and password directly in application. This way is more secure, but a little bit complex.

Create your application in Azure Portal

To use Microsoft/Office365 OAUTH in your application, you must create a application in https://portal.azure.com.

Sign in to the Azure portal using either a work or school account or a personal Microsoft account.
If your account gives you access to more than one tenant, select your account in the top right corner, and set your portal session to the Azure AD tenant that you want.
In the left-hand navigation pane, select the Azure Active Directory service, and then select App registrations > New registration.

Single tenant and multitenant in account type

When the register an application page appears, enter a meaningful application name and select the account type.

Select which accounts you would like your application to support.

If your application only supports the users in your directory or organization, please select Single tenant type;
If your application needs to support all users in Office 365 and Microsoft personal account (hotmail.com, outlook.com), please select Multitenant type, and you must verify publisher.

Because we want to support all Office 365 and LIVE SDK (hotmail, outlook personal account), so select Accounts in any organizational directory and personal Microsoft accounts.

API Permission

Now we need to add permission to the application:

Click API Permission -> Add a permission -> Microsoft Graph -> Delegated Permission -> User.Read, email, offline_access, openid, profile, SMTP.Send, IMAP.AccessAsUser.All, POP.AccessAsUser.All and Mail.Send.

EWS API permission

With the above permissions, your application can support SMTP, POP and IMAP and Ms Graph API service. If your application needs to support EWS protocol either, add EWS permission like this:

Click API Permission -> Add a permission -> APIs in my organization uses -> Office 365 Exchange Online -> Delegated Permission -> Check EWS.AccessAsUser.All

Here is permissions list:

Authentication and redirect uri

Click "Authentication" -> Add a platform -> Mobile and desktop applications -> Redirect Uri, please check or add the following URI.
```
https://login.microsoftonline.com/common/oauth2/nativeclient
https://login.live.com/oauth20_desktop.srf
http://127.0.0.1
                
```
* "https://login.live.com/oauth20_desktop.srf" is used for Live SDK, "http://127.0.0.1" is used for local Http Listener.
If your application needs to support Microsoft personal account, set both "Live SDK Support" and "Treat application as a public client" to "Yes".
If your application is web application, you should use a page to get authorization code instead of HttpListener. You need to add your page path to Authentication -> add a platform -> web -> Redirect URIs in your Azure application.

Client Id and client secrets

Now we need to create a client secret for the application, click Certificates and secrets -> client secrets and add a new client secret.

After client secret is created, store the client secret value to somewhere, Please store client secret value by yourself, because it is hidden when you view it at next time.

Branding and verify publisher

Now we click Branding, you can edit your company logo, URL and application name. If your application supports multitenant (access user in all Office 365 and Microsoft personal account), you must complete the publisher verification.

It is not difficult, you can have a look at publisher verification. After publisher verification is completed, your branding is like this:

You must complete the publisher verification for multitenant application, otherwise, your application will not request access token correctly.

Client id and tenant

Now you can click Overview to find your client id and tenant.

If your application is single tenant, use the tenant value in tokenUri and authUri instead of "common". If your application is multitenant, use "common" as tenant.

Above client_id and secret support both "Office365 + SMTP/POP/IMAP/EWS" and "Live (hotmail, outlook personal account) + SMTP/POP/IMAP".

Use client id and client secret to request access token

You can use client id and client secret to get the user email address and access token like this:

Your application uses a web browser/browser control to open OAUTH URL;
User inputs user and password in Web Authentication, the server returns access token back to your application
Your application uses access token to access the server. You can find the example codes in EASendMail Installation Path\Samples_{Programming language/Developer Tool}\Oauth.* project.

Access token expiration and refresh token

You don’t have to open browser to request access token every time. By default, access token expiration time is 3600 seconds, you can use the access token repeatedly before it is expired. After it is expired, you can use refresh token to refresh access token directly without opening browser. You can find full sample project in EASendMail installation path to learn how to refresh token.

You should create your client id and client secret, don't use the client id in the sample project, it is only for test purpose. If you got "This app isn't verified" information, please click "advanced" -> Go to ... for test.

Use access token to send email with Office 365 EWS protocol

After you get user email address and access token, you can use the following codes to send email using Office365 EWS protocol.

Example

[Visual Basic, C#, C++] To get the full samples of EASendMail, please refer to Samples section.

[VB6 - Send Email using Office365 EWS OAUTH Authentication]

Const ConnectNormal = 0
Const ConnectSSLAuto = 1
Const ConnectSTARTTLS = 2
Const ConnectDirectSSL = 3
Const ConnectTryTLS = 4

Const AuthAuto = -1
Const AuthLogin = 0
Const AuthNtlm = 1
Const AuthCramMd5 = 2
Const AuthPlain = 3
Const AuthMsn = 4
Const AuthXoauth2 = 5

Private Sub SendEmail(email As String, access_token As String)
    Dim oSmtp As EASendMailObjLib.Mail
    Set oSmtp = New EASendMailObjLib.Mail
    oSmtp.LicenseCode = "TryIt"

    ' Office365 server address
    oSmtp.ServerAddr = "outlook.office365.com"

    ' Office365 Ms Graph API server address
    ' oSmtp.ServerAddr = "https://graph.microsoft.com/v1.0/me/sendMail"

    ' Set Exchange Web Service Protocol - EWS - Exchange 2007/2010/2013/2016/2019/Office365
    oSmtp.Protocol = 1

    ' oSmtp.Protocol = 4 ' you can use Ms Graph API

    ' Enable SSL/TLS connection
    oSmtp.ConnectType = ConnectSSLAuto

    ' OAUTH/XOAUTH2 type
    oSmtp.AuthType = AuthXoauth2 
    oSmtp.UserName = email
    oSmtp.Password = access_token
    
    oSmtp.FromAddr = email
    oSmtp.AddRecipient "Support Team", "support@emailarchitect.net", 0
    
    oSmtp.BodyText = "Hello, this is a test...."
    If oSmtp.SendMail() = 0 Then
    MsgBox "Message delivered!"
    Else
    MsgBox oSmtp.GetLastErrDescription()
    End If

End Sub


[Visual C++ - Send Email using Office365 EWS OAUTH Authentication]

#include "stdafx.h"
#include <tchar.h>
#include <Windows.h>

#include "EASendMailObj.tlh"
using namespace EASendMailObjLib;

const int ConnectNormal = 0;
const int ConnectSSLAuto = 1;
const int ConnectSTARTTLS = 2;
const int ConnectDirectSSL = 3;
const int ConnectTryTLS = 4;

const int AuthAuto = -1;
const int AuthLogin = 0;
const int AuthNtlm = 1;
const int AuthCramMd5 = 2;
const int AuthPlain = 3;
const int AuthMsn = 4;
const int AuthXoauth2 = 5;
    
void SendEmail(const TCHAR* lpszEmail, const TCHAR* lpszAccessToken)
{
    ::CoInitialize(NULL);
    IMailPtr oSmtp = NULL;
    oSmtp.CreateInstance(__uuidof(EASendMailObjLib::Mail));
    oSmtp->LicenseCode = _T("TryIt");
    
    // Office365 EWS server address
    oSmtp->ServerAddr = _T("outlook.office365.com");
    
    // Office365 Ms Graph API server address
    // oSmtp->ServerAddr = _T("https://graph.microsoft.com/v1.0/me/sendMail");

    // Set Exchange Web Service Protocol - EWS - Exchange 2007/2010/2013/2016/2019/Office365
    oSmtp->Protocol = 1;

    // oSmtp->Protocol = 4; // you can use Ms Graph API

    // Enable SSL/TLS connection
    oSmtp->ConnectType = ConnectSSLAuto;

    // OAUTH type
    oSmtp->AuthType = AuthXoauth2; 
    oSmtp->UserName = lpszEmail;
    oSmtp->Password = lpszAccessToken;
    
    oSmtp->FromAddr = lpszEmail;
    oSmtp->AddRecipient(_T("Support Team"), 
                            _T("support@emailarchitect.net"), 0);
    
    
    oSmtp->BodyText = _T("Hello, this is a test....");
    if (oSmtp->SendMail() == 0)
    _tprintf(_T("Message delivered!"));
    else
    _tprintf((const TCHAR*)oSmtp->GetLastErrDescription());
}


[Delphi - Send Email using Office365 EWS OAUTH Authentication]

const
    ConnectNormal = 0;
    ConnectSSLAuto = 1;
    ConnectSTARTTLS = 2;
    ConnectDirectSSL = 3;
    ConnectTryTLS = 4;

    AuthAuto = -1;
    AuthLogin = 0;
    AuthNtlm = 1;
    AuthCramMd5 = 2;
    AuthPlain = 3;
    AuthMsn = 4;
    AuthXoauth2 = 5;

procedure TForm1.SendEmail(email: string, accesstoken: string);
var
    oSmtp : TMail;
begin
    oSmtp := TMail.Create(Application);
    oSmtp.LicenseCode := 'TryIt';

    // Office365 EWS server address
    oSmtp.ServerAddr := 'outlook.office365.com';

    // Office365 Ms Graph API server address
    // oSmtp.ServerAddr := 'https://graph.microsoft.com/v1.0/me/sendMail';

    // Set Exchange Web Service Protocol - EWS - Exchange 2007/2010/2013/2016/2019/Office365
    oSmtp.Protocol := 1;

    // oSmtp.Protocol := 4; // you can use Ms Graph API

    // Enable SSL/TLS connection
    oSmtp.ConnectType := ConnectSSLAuto;

    // OAUTH/XOAUTH2 type
    oSmtp.AuthType := AuthXoauth2; 
    oSmtp.UserName := email;
    oSmtp.Password := accesstoken;

    // Set sender email address
    oSmtp.FromAddr := email;

    // Add recipient email address
    oSmtp.AddRecipientEx('support@emailarchitect.net', 0);

    // Set email subject
    oSmtp.Subject := 'simple email from Delphi project';

    // Set email body
    oSmtp.BodyText := 'this is a test email sent from Delphi project, do not reply';
    
    ShowMessage('start to send email ...');

    if oSmtp.SendMail() = 0 then
        ShowMessage('email was sent successfully!')
    else
        ShowMessage('failed to send email with the following error: '
        + oSmtp.GetLastErrDescription());

end;

end.

Remarks

If your application is background service which doesn't support user interaction, please have a look at this topic: Use Office365 OAUTH with Background Service.

If you don't want to use OAUTH 2.0, Office 365 also supports traditional user authentication.

Online Example

VB6 - Send Email using Google/Gmail OAuth 2.0 Authentication
VB6 - Send Email using Gmail/G Suite OAuth 2.0 in Background Service (Service Account)
VB6 - Send Email using Microsoft OAuth 2.0 (Modern Authentication) from Hotmail/Outlook Account
VB6 - Send Email using Microsoft OAuth 2.0 (Modern Authentication) + EWS Protocol from Office 365 Account
VB6 - Send Email using Microsoft OAuth 2.0 (Modern Authentication) + EWS Protocol from Office 365 in Background Service

Delphi - Send Email using Google/Gmail OAuth 2.0 Authentication
Delphi - Send Email using Gmail/G Suite OAuth 2.0 in Background Service (Service Account)
Delphi - Send Email using Microsoft OAuth 2.0 (Modern Authentication) from Hotmail/Outlook Account
Delphi - Send Email using Microsoft OAuth 2.0 (Modern Authentication) + EWS Protocol from Office 365 Account
Delphi - Send Email using Microsoft OAuth 2.0 (Modern Authentication) + EWS Protocol from Office 365 in Background Service

Visual C++ - Send Email using Google/Gmail OAuth 2.0 Authentication
Visual C++ - Send Email using Gmail/G Suite OAuth 2.0 in Background Service (Service Account)
Visual C++ - Send Email using Microsoft OAuth 2.0 (Modern Authentication) from Hotmail/Outlook Account
Visual C++ - Send Email using Microsoft OAuth 2.0 (Modern Authentication) + EWS Protocol from Office 365 Account
Visual C++ - Send Email using Microsoft OAuth 2.0 (Modern Authentication) + EWS Protocol from Office 365 in Background Service