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

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

However Microsoft will disable traditional user authentication in the future, switching to Microsoft OAuth (Modern Authentication) is strongly recommended now.

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 C++ project, the first step is “Add header files of EASendMail to your project”. Please go to C:\Program Files\EASendMail\Include\tlh or C:\Program Files (x86)\EASendMail\Include\tlh folder, find easendmailobj.tlh and easendmailobj.tli, and then copy these files to your project folder.

add reference in Visual C++

Office 365 OAuth 2.0 client credentials grant

Normal OAuth requires user input user/password for authentication. Obviously, it is not suitable for background service. In this case, You can use the OAuth 2.0 client credentials grant, sometimes called two-legged OAuth, to access web-hosted resources by using the identity of an application. It only works for Office365 user, it doesn’t work for personal Hotmail account.

Create your application in Azure Portal

To use Microsoft/Office365/Live OAuth (Modern Authentication) in your application, you must create a application in Azure Portal.

Important

You can use any Microsoft user to create the application, it doesn’t require application owner is administrator in your Office365 domain. But your Office365 administrator must authorize the application to access user mailbox.

  • 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.
azure portal new app 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 just need to support Offic365 user in our organization, so select Accounts in this organizational directory only (single tenant).

Do not select supporting Microsoft personal account, because there is no way to access Microsoft personal account in background service.

Important

If you don’t verify publisher for multitenant application, your application will not request access token successfully.

API permissions

  • Click API Permission -> Microsoft Graph -> Delegated Permission -> User.Read.
  • Click API Permission -> Microsoft Graph -> Application Permission -> Mail.Send.
  • Click API Permission -> Add a permission -> APIs in my organization uses -> Office 365 Exchange Online -> Application Permission -> Other permission -> full_access_as_app
azure APIs in my organization uses

Here is permissions list:

azure application api permission list

If your current user is not a user in a verified domain or Offic 365, you will not find Office 365 Exchange Online in API list, then you have to add this API permission manually.

  • Select Manifest in the left-hand navigation under Manage.
  • Locate the requiredResourceAccess property in the manifest, and add the following inside the square brackets ([]):
{
  "resourceAppId": "00000002-0000-0ff1-ce00-000000000000",
  "resourceAccess": [
      {
          "id": "dc890d15-9560-4a4c-9b7f-a736ec74ec40",
          "type": "Role"
      }
  ]
}
  • Select Save.
  • Select API permissions under Manage. Confirm that the full_access_as_app permission is listed.

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.

azure application api permission

After client secret is created, store the client secret value to somewhere.

Important

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:

azure application Authentication Overview

Important

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.

azure application client id and tenant

Access token expiration

You don’t have 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.

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.

Delphi - Send email using Microsoft OAuth + EWS 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 := '79a42c6f-5a9a-439b-a2ca-7aa1b0ed9776';
    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 = '8f54719b-4070-41ae-91ad-f48e3c793c5f';
    client_secret: WideString = 'cbmYyGQjz[d29wL2ArcgoO7HLwJXL/-.';
    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 EWS 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.

Delphi - Send email using Microsoft OAuth + Ms Grap API 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 := '79a42c6f-5a9a-439b-a2ca-7aa1b0ed9776';
    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 = '8f54719b-4070-41ae-91ad-f48e3c793c5f';
    client_secret: WideString = 'cbmYyGQjz[d29wL2ArcgoO7HLwJXL/-.';
    scope: WideString = 'https://graph.microsoft.com/Mail.Send';
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 := 'https://graph.microsoft.com/v1.0/me/sendMail';

    // 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.

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

Appendix

Comments

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