How to Authenticate with Microsoft Outlook using OAuth2 and Apache Camel

First, you’ll need to register your application with Microsoft and get your client ID and secret. You can follow the instructions here: https://docs.microsoft.com/en-us/azure/active-directory/develop/quickstart-register-app
Add the following dependencies to your Camel project:

<dependency>
    <groupId>org.apache.camel</groupId>
    <artifactId>camel-mail</artifactId>
    <version>${camel.version}</version>
</dependency>
<dependency>
    <groupId>com.microsoft.azure</groupId>
    <artifactId>msal4j</artifactId>
    <version>1.11.1</version>
</dependency>

Create a class to hold your OAuth2 credentials:

public class OutlookOAuth2Credentials {

    private final String clientId;
    private final String clientSecret;
    private final String tenantId;
    private final String authority;
    private final String[] scopes;

    public OutlookOAuth2Credentials(String clientId, String clientSecret, String tenantId, String authority, String[] scopes) {
        this.clientId = clientId;
        this.clientSecret = clientSecret;
        this.tenantId = tenantId;
        this.authority = authority;
        this.scopes = scopes;
    }

    public String getClientId() {
        return clientId;
    }

    public String getClientSecret() {
        return clientSecret;
    }

    public String getTenantId() {
        return tenantId;
    }

    public String getAuthority() {
        return authority;
    }

    public String[] getScopes() {
        return scopes;
    }
}

Create a class to retrieve an access token using the MSAL library:

public class OutlookOAuth2TokenProvider {

    private final IConfidentialClientApplication app;
    private final String[] scopes;

    public OutlookOAuth2TokenProvider(String clientId, String clientSecret, String tenantId, String authority, String[] scopes) throws MalformedURLException {

        app = ConfidentialClientApplication
                .builder(clientId, ClientCredentialFactory.createFromSecret(clientSecret))
                .authority(authority + tenantId)
                .build();

        this.scopes = scopes;
    }

    public String getAccessToken() throws MalformedURLException {

        IAuthenticationResult result = app.acquireToken(ClientCredentialParameters
                .builder(scopes)
                .build())
                .join();

        return result.accessToken();
    }
}

Create a custom MailAuthenticator to retrieve the access token from the OutlookOAuth2TokenProvider class:

public class OutlookOAuth2Authenticator extends MailAuthenticator {

    private final OutlookOAuth2TokenProvider tokenProvider;

    public OutlookOAuth2Authenticator(OutlookOAuth2TokenProvider tokenProvider) {
        this.tokenProvider = tokenProvider;
    }

    @Override
    public PasswordAuthentication getPasswordAuthentication() {

        try {
            String accessToken = tokenProvider.getAccessToken();

            return new PasswordAuthentication("", accessToken.toCharArray());
        } catch (MalformedURLException e) {
            throw new RuntimeException(e);
        }
    }
}

Finally, configure your mail endpoint to use the OutlookOAuth2Authenticator:

from("imaps://outlook.office365.com?username=<your_email_address>&delete=false&unseen=true&delay=300000&debugMode=true")
    .routeId("outlook-route")
    .setProperty("CamelMailOAuth2Authenticator", constant(new OutlookOAuth2Authenticator(
            new OutlookOAuth2TokenProvider(
                    "<your_client_id>",
                    "<your_client_secret>",
                    "<your_tenant_id>",
                    "https://login.microsoftonline.com/",
                    new String[]{"https://outlook.office365.com/.default"}))))
    .to("file:/path/to/your/output/folder?fileName=outlook-${date:now:yyyyMMdd}.txt");

In the code above, replace <your_email_address>, <your_client_id>, <your_client_secret>, and <your_tenant_id> with your own values.
Also, note that the scopes for Outlook access in this example are set to "https://outlook.office365.com/.default". You may need to adjust these based on your specific use case.
Finally, in your CamelContext configuration, you’ll need to add the following properties to enable OAuth2 authentication:

mail.smtp.auth=true
mail.smtp.auth.mechanisms=OAUTH2
mail.smtp.sasl.mechanisms=OAUTH2
mail.smtp.sasl.authorizationid=<your_email_address>

That’s it! With these changes, your Camel route will now authenticate with Microsoft Outlook using OAuth2 instead of basic authentication.

Java

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