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Delphi - Send email using Microsoft OAuth 2.0 (Modern Authentication) + EWS/Ms Graph API/SMTP protocol from Office 365 in background service

You can send email using traditional user/password authentication from Office 365 account by EWS/SMTP Protocol.

However Microsoft has disabled traditional user authentication in many tenants, switching to Microsoft OAuth (Modern Authentication) is strongly recommended now.

In this topic, I will introduce how to send email using Delphi and Microsoft OAuth (Modern Authentication) in background service.

Installation

EASendMail is a SMTP component which supports all operations of SMTP/ESMTP protocols (RFC 821, RFC 822, RFC 2554). Before you can use the following example codes, you should download the EASendMail Installer and install it on your machine at first.

Add reference

To use EASendMail SMTP ActiveX Object in your Delphi project, the first step is “Add Unit file of EASendMail to your project”. Please go to C:\Program Files\EASendMail\Include\delphi or C:\Program Files (x86)\EASendMail\Include\delphi folder, find EASendMailObjLib_TLB.pas, and then copy this file to your project folder.

unit Unit1;

interface
// include EASendMailObjLib_TLB unit to your Delphi Project
uses
Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
Dialogs, EASendMailObjLib_TLB, StdCtrls;

You can also create “EASendMailObjLib_TLB.pas” manually like this:

  • Delphi 7

    Please choose menu -> Project -> Import Type Library and select EASendMailObj ActiveX Object, click Create Unit, the reference of EASendMail ActiveX Object will be added to your project.

    add reference in Delphi

  • Delphi XE

    If you use Delphi XE to import the Type library, Please choose menu -> Component -> Import Component -> Import Type Library -> and select EASendMailObj ActiveX Object -> have Generate Component Wrapper checked -> Create Unit.

Then you can start to use it in your Delphi Project.

Office 365 OAuth 2.0 client credentials grant

Normal OAuth requires user to input user and password in browser for authentication. Obviously, it is not suitable for background service.

The solution is granting admin consent to the azure application, then the application can use the client secret value to request the access token directly. This way doesn’t require user attending, it is suitable for background service.

This tutorial introduces how to register application for background service in Azure Portal, then assign the Graph API/EWS/SMTP/POP/IMAP API permission to the application and add the access right to the mailbox of specific user.

Register the application in Azure Portal

Sign in to the Azure Portal using the Microsoft account of the Office 365 administrator. 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.

Search Microsoft Entra ID (old name “Azure Active Directory”) and go to this service:

go to azure active directory

Register application

In the left-hand navigation pane, select the Microsoft Entra ID service, and then select -> Manage -> App registrations -> New registration.

register app in azure

Input a name to to register the application:

register app in azure

Find the application id (client id) and tenant id

After the application is registered, you can click Overview to find the client id and tenant id. These are required parameters for requesting access token.

client int of azure app

Assign API permission

Now you need to assign API permission to the application by clicking Manage -> API Permission -> Add a permission.

add api permission to app in azure

You don’t have to assign all the API permissions below to the application, just assign the API permission(s) you need.

Protocol Permission Scope
Graph API Mail.Send, Mail.ReadWrite https://graph.microsoft.com/.default
EWS full_access_as_app https://outlook.office365.com/.default
SMTP SMTP.AccessAsApp https://outlook.office365.com/.default
POP POP.AccessAsApp https://outlook.office365.com/.default
IMAP IMAP.AccessAsApp https://outlook.office365.com/.default

Graph API permission

Go to Microsoft APIs -> Microsoft Graph -> Application Permission ->

add graph api permission to app in azure

Add Mail.Send and Mail.ReadWrite permission

add Graph Mail.Send Mail.ReadWrite permission to app in azure

EWS and SMTP/POP/IMAP permission

Go to APIs in my organization uses -> Office 365 Exchange Online -> Application Permission ->

add exchange online permission to app in azure

Add full_access_app permission

add exchange online EWS permission to app in azure

Add POP.AccessAsApp permission

add exchange online POP permission to app in azure

Add IMAP.AccessAsApp permission

add exchange online IMAP permission to app in azure

Add SMTP.AccessAsApp permission

add exchange online SMTP permission to app in azure

Complete permissions list

api permission overview in azure

Create client secret

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

add client secret in azure add client secret in azure

Store client secret value

After client secret is created, store the client secret value to somewhere. It is another required parameter for requesting access token.

copy client secret value

Important

Please store client secret value by yourself, because it is hidden when you view it at next time.

Now you can use the client id, tenant id and client secret value to request access token. But to use SMTP/POP/IMAP protocol, you need to Register SMTP/POP/IMAP service principals in Exchange as well.

Important

You should create your client id and client secret, do not use the client id from example codes in production environment, it is used for test purpose. If you got "This app isn't verified" information, please click "Advanced" -> Go to ... for test.

Now you can use the following example codes to send email with Graph API or EWS protocol:

Delphi - Send email using Ms Grap API + Microsoft OAuth from Office 365 account in background service - example

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;

function TForm1.RequestAccessToken(requestData: WideString): WideString;
var
    httpRequest: TServerXMLHTTP;
    oauthParser: TOAuthResponseParser;
    fullRequest: OleVariant;
    status: integer;
    responseText: WideString;
    accessToken: WideString;
    tokenUri, tenant_id: WideString;
begin
    result := '';

    httpRequest := TServerXMLHTTP.Create(Application);

    fullRequest :=  requestData;

    // If your application is not created by Office365 administrator,
    // please use Office365 directory tenant id, you should ask Offic365 administrator to send it to you.
    // Office365 administrator can query tenant id in https://portal.azure.com/ - Azure Active Directory.
    tenant_id := '2ea4955d-830e-4aa7-8ab5-661a6b9aa84d';
    tokenUri := 'https://login.microsoftonline.com/' + tenant_id + '/oauth2/v2.0/token';

    httpRequest.setOption(2, 13056);
    httpRequest.open('POST', tokenUri, true);
    httpRequest.setRequestHeader('Content-Type', 'application/x-www-form-urlencoded');
    httpRequest.send(fullRequest);

    while( httpRequest.readyState <> 4 ) do
    begin
        try
            httpRequest.waitForResponse(1);
            Application.ProcessMessages();
        except
            ShowMessage('Server response timeout (access token).');
            exit;
        end;
    end;

    status := httpRequest.status;
    responseText := httpRequest.responseText;

    if (status < 200) or (status >= 300) then
    begin
        ShowMessage('Failed to get access token from server.' + responseText);
        exit;
    end;

    oauthParser := TOAuthResponseParser.Create(Application);
    oauthParser.Load(responseText);

    accessToken := oauthParser.AccessToken;

    if accessToken = '' then
    begin
        ShowMessage('Failed to parse access token from server response.');
        exit;
    end;

    result := accessToken;
end;

function TForm1.GenerateRequestData(): WideString;
const
    client_id: WideString = 'b22194da-44d6-4320-a067-e86a275d6fa4';
    client_secret: WideString = 'VTO8Q~eo0JCXc291jcM4wnhZ_GXyKMu.';
    scope: WideString = 'https://graph.microsoft.com/.default';
begin
    result := 'client_id=' + client_id
            + '&client_secret=' + client_secret
            + '&scope=' + scope
            + '&grant_type=client_credentials';
end;

procedure TForm1.SendEmail();
var
    oSmtp : TMail;
    accessToken: WideString;
    Office365User: WideString;
begin

    accessToken := RequestAccessToken(GenerateRequestData());
    if accessToken = '' then
        exit;

    Office365User := 'user@mydomain.onmicrosoft.com';

    oSmtp := TMail.Create(Application);
    oSmtp.LicenseCode := 'TryIt';

    // Office365 Ms Graph API server address
    oSmtp.ServerAddr := 'graph.microsoft.com';

    // Set Office365 Ms Graph API protocol
    oSmtp.Protocol := 4;

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

    // OAUTH/XOAUTH2 type
    oSmtp.AuthType := AuthXoauth2;
    oSmtp.UserName := Office365User;
    oSmtp.Password := accessToken;

    // Set sender email address
    oSmtp.FromAddr := Office365User;

    // 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.

Delphi - Send email using EWS + Microsoft OAuth from Office 365 account in background service - example

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;

function TForm1.RequestAccessToken(requestData: WideString): WideString;
var
    httpRequest: TServerXMLHTTP;
    oauthParser: TOAuthResponseParser;
    fullRequest: OleVariant;
    status: integer;
    responseText: WideString;
    accessToken: WideString;
    tokenUri, tenant_id: WideString;
begin
    result := '';

    httpRequest := TServerXMLHTTP.Create(Application);

    fullRequest :=  requestData;

    // If your application is not created by Office365 administrator,
    // please use Office365 directory tenant id, you should ask Offic365 administrator to send it to you.
    // Office365 administrator can query tenant id in https://portal.azure.com/ - Azure Active Directory.
    tenant_id := '2ea4955d-830e-4aa7-8ab5-661a6b9aa84d';
    tokenUri := 'https://login.microsoftonline.com/' + tenant_id + '/oauth2/v2.0/token';

    httpRequest.setOption(2, 13056);
    httpRequest.open('POST', tokenUri, true);
    httpRequest.setRequestHeader('Content-Type', 'application/x-www-form-urlencoded');
    httpRequest.send(fullRequest);

    while( httpRequest.readyState <> 4 ) do
    begin
        try
            httpRequest.waitForResponse(1);
            Application.ProcessMessages();
        except
            ShowMessage('Server response timeout (access token).');
            exit;
        end;
    end;

    status := httpRequest.status;
    responseText := httpRequest.responseText;

    if (status < 200) or (status >= 300) then
    begin
        ShowMessage('Failed to get access token from server.' + responseText);
        exit;
    end;

    oauthParser := TOAuthResponseParser.Create(Application);
    oauthParser.Load(responseText);

    accessToken := oauthParser.AccessToken;

    if accessToken = '' then
    begin
        ShowMessage('Failed to parse access token from server response.');
        exit;
    end;

    result := accessToken;
end;

function TForm1.GenerateRequestData(): WideString;
const
    client_id: WideString = 'b22194da-44d6-4320-a067-e86a275d6fa4';
    client_secret: WideString = 'VTO8Q~eo0JCXc291jcM4wnhZ_GXyKMu.';
    scope: WideString = 'https://outlook.office365.com/.default';
begin
    result := 'client_id=' + client_id
            + '&client_secret=' + client_secret
            + '&scope=' + scope
            + '&grant_type=client_credentials';
end;

procedure TForm1.SendEmail();
var
    oSmtp : TMail;
    accessToken: WideString;
    Office365User: WideString;
begin

    accessToken := RequestAccessToken(GenerateRequestData());
    if accessToken = '' then
        exit;

    Office365User := 'user@mydomain.onmicrosoft.com';

    oSmtp := TMail.Create(Application);
    oSmtp.LicenseCode := 'TryIt';

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

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

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

    // OAUTH/XOAUTH2 type
    oSmtp.AuthType := AuthXoauth2;
    oSmtp.UserName := Office365User;
    oSmtp.Password := accessToken;

    // Set sender email address
    oSmtp.FromAddr := Office365User;

    // 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.

Register SMTP/POP/IMAP service principals in Exchange

Although the application is consented by the tenant admin, but to access SMTP/POP/IMAP service, the tenant administrator still need to register your application as service principal in Exchange via Exchange Online PowerShell. This is enabled by the New-ServicePrincipal cmdlet.

New-ServicePrincipal -AppId <APPLICATION_ID> -ServiceId <OBJECT_ID>

Find APPLICATION_ID and OBJECT_ID

You should find your APPLICATION_ID and OBJECT_ID before running above cmdlet. Go to Overview -> Managed application in local directory:

Managed application in local directory

After you click your application name in Managed application in l..., you can see Application ID and Object ID for New-ServicePrincipal cmdlet.

find object id in Managed application in local directory

Open Exchange Online PowerShell

Now you need to open Exchange Online PowerShell to run the cmdlet. If you have not installed the module, you can use the Install-Module cmdlet to install the module from the PowerShell Gallery.

Install-Module -Name ExchangeOnlineManagement

After you’ve installed the module, open a PowerShell window and load the module by running the following command:

Import-Module ExchangeOnlineManagement

Connect-ExchangeOnline -UserPrincipalName "admin@yourdomain.onmicrosoft.com"

Create service principal

After Exchange Online PowerShell is connected successfully, run the following cmdlet to create a new service principal: The ServiceId is the OBJECT_ID and the AppId is APPLICATION_ID found in Find APPLICATION_ID and OBJECT_ID

New-ServicePrincipal -AppId "b22194da-44d6-4320-a067-e86a275d6fa4" -ServiceId "71941e67-ef24-45e8-bd22-dfd53790bb77"

Query service principal

After you create the service principal, you can query it by:

Get-ServicePrincipal

Add permission to specific user

You can now add the specific mailboxes in the tenant that will be allowed to be access by your application. This is done with the Add-MailboxPermission cmdlet.

Add-MailboxPermission -Identity <mailboxIdParameter> -User <SecurityPrincipalIdParameter|OBJECT_ID>  -AccessRights <MailboxRights[]>

For example:

Add-MailboxPermission -Identity "grant-test@emailarchitect.net" -User "71941e67-ef24-45e8-bd22-dfd53790bb77" -AccessRights FullAccess

Query permission

You can also query the permission by:

Get-MailboxPermission -Identity "grant-test@emailarchitect.net"

Now you can use SMTP protocol to send email by the following codes:

Delphi - Send email using SMTP + Microsoft OAuth from Office 365 account in background service - example

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;

function TForm1.RequestAccessToken(requestData: WideString): WideString;
var
    httpRequest: TServerXMLHTTP;
    oauthParser: TOAuthResponseParser;
    fullRequest: OleVariant;
    status: integer;
    responseText: WideString;
    accessToken: WideString;
    tokenUri, tenant_id: WideString;
begin
    result := '';

    httpRequest := TServerXMLHTTP.Create(Application);

    fullRequest :=  requestData;

    // If your application is not created by Office365 administrator,
    // please use Office365 directory tenant id, you should ask Offic365 administrator to send it to you.
    // Office365 administrator can query tenant id in https://portal.azure.com/ - Azure Active Directory.
    tenant_id := '2ea4955d-830e-4aa7-8ab5-661a6b9aa84d';
    tokenUri := 'https://login.microsoftonline.com/' + tenant_id + '/oauth2/v2.0/token';

    httpRequest.setOption(2, 13056);
    httpRequest.open('POST', tokenUri, true);
    httpRequest.setRequestHeader('Content-Type', 'application/x-www-form-urlencoded');
    httpRequest.send(fullRequest);

    while( httpRequest.readyState <> 4 ) do
    begin
        try
            httpRequest.waitForResponse(1);
            Application.ProcessMessages();
        except
            ShowMessage('Server response timeout (access token).');
            exit;
        end;
    end;

    status := httpRequest.status;
    responseText := httpRequest.responseText;

    if (status < 200) or (status >= 300) then
    begin
        ShowMessage('Failed to get access token from server.' + responseText);
        exit;
    end;

    oauthParser := TOAuthResponseParser.Create(Application);
    oauthParser.Load(responseText);

    accessToken := oauthParser.AccessToken;

    if accessToken = '' then
    begin
        ShowMessage('Failed to parse access token from server response.');
        exit;
    end;

    result := accessToken;
end;

function TForm1.GenerateRequestData(): WideString;
const
    client_id: WideString = 'b22194da-44d6-4320-a067-e86a275d6fa4';
    client_secret: WideString = 'VTO8Q~eo0JCXc291jcM4wnhZ_GXyKMu.';
    scope: WideString = 'https://outlook.office365.com/.default';
begin
    result := 'client_id=' + client_id
            + '&client_secret=' + client_secret
            + '&scope=' + scope
            + '&grant_type=client_credentials';
end;

procedure TForm1.SendEmail();
var
    oSmtp : TMail;
    accessToken: WideString;
    Office365User: WideString;
begin

    accessToken := RequestAccessToken(GenerateRequestData());
    if accessToken = '' then
        exit;

    Office365User := 'grant-test@emailarchitect.net';

    oSmtp := TMail.Create(Application);
    oSmtp.LicenseCode := 'TryIt';

    // Office365 SMTP server address
    oSmtp.ServerAddr := 'outlook.office365.com';
    oSmtp.ServerPort := 587;

    // Don't set protocol, use default SMTP protocol

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

    // OAUTH/XOAUTH2 type
    oSmtp.AuthType := AuthXoauth2;
    oSmtp.UserName := Office365User;
    oSmtp.Password := accessToken;

    // Set sender email address
    oSmtp.FromAddr := Office365User;

    // 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.

Access token lifetime

You don’t have to request access token every time. By default, access token expiration time is 3600 seconds, you can reuse the access token repeatedly before it is expired.

TLS 1.2 protocol

TLS is the successor of SSL, more and more SMTP servers require TLS 1.2 encryption now.

If your operating system is Windows XP/Vista/Windows 7/Windows 2003/2008/2008 R2/2012/2012 R2, you need to enable TLS 1.2 protocol in your operating system like this:

Enable TLS 1.2 on Windows XP/Vista/7/10/Windows 2008/2008 R2/2012

EA Oauth Service for Office 365

If you are not the tenant administrator and you don’t have the permission to create or grant the application in Azure, or if your code is too complex or out of maintenance, and you don’t want to change anything in your source codes, then you can have a try with EA Oauth Service for Offic365. It provides an easy way for the legacy email application that doesn’t support OAUTH 2.0 to send and retrieve email from Office 365 without changing any codes. SMTP, POP, IMAP and SSL/TLS protocols are supported.

Appendix

Comments

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See Also