Issue 53534: Support Microsoft's Graph Protocol API for authentication via OAuth2 token

api/build.gradle

@@ -128,6 +128,40 @@ dependencies {
         )
     )
 
+    // Microsoft Graph SDK for sending OAuth2-authenticated notification emails
+    BuildUtils.addExternalDependency(
+        project,
+        new ExternalDependency(
+            "com.microsoft.graph:microsoft-graph:${microsoftGraphVersion}",
+            "Microsoft Graph SDK",
+            "Microsoft",
+            "https://github.com/microsoftgraph/msgraph-sdk-java",
+            "MIT License",
+            "https://opensource.org/licenses/MIT",
+            "Library to interact with Microsoft Graph API including sending emails",
+        )
+    )
+
+    // Azure Identity library for OAuth2 token authentication and built-in token management capabilities
+    BuildUtils.addExternalDependency(
+        project,
+        new ExternalDependency(
+            "com.azure:azure-identity:${azureIdentityVersion}",
+            "Azure Identity Library",
+            "Microsoft",
+            "https://github.com/Azure/azure-sdk-for-java/tree/main/sdk/identity/azure-identity",
+            "MIT License",
+            "https://opensource.org/licenses/MIT",
+            "Library to handle OAuth2 authentication with Microsoft’s identity platform",
+        ),
+        {
+            // This module pulls in JNA for native OS credential store access; but its not needed for
+            // client credentials flow as it uses in-memory token caching. The version of JNA that gets
+            // pulled in here conflicts with the JNA version used by the docker module.
+            exclude group: "com.microsoft.azure", module: "msal4j-persistence-extension"
+        }
+    )
+
     BuildUtils.addExternalDependency(
         project,
         new ExternalDependency(

api/src/org/labkey/api/ApiModule.java

@@ -155,6 +155,7 @@
 import org.labkey.api.util.FileStream;
 import org.labkey.api.util.FileType;
 import org.labkey.api.util.FileUtil;
+import org.labkey.api.util.GraphTransportProvider;
 import org.labkey.api.util.HelpTopic;
 import org.labkey.api.util.JSoupUtil;
 import org.labkey.api.util.JobRunner;
@@ -397,6 +398,7 @@ public void registerServlets(ServletContext servletCtx)
             FileType.TestCase.class,
             FileUtil.TestCase.class,
             GenerateUniqueDataIterator.TestCase.class,
+            GraphTransportProvider.TestCase.class,
             HelpTopic.TestCase.class,
             InlineInClauseGenerator.TestCase.class,
             JSONDataLoader.HeaderMatchTest.class,

api/src/org/labkey/api/util/EmailTransportProvider.java

@@ -0,0 +1,57 @@
+/*
+ * Copyright (c) 2026 LabKey Corporation
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.labkey.api.util;
+
+import jakarta.mail.Message;
+import jakarta.mail.MessagingException;
+
+import java.util.Properties;
+
+/**
+ * Interface for email transport providers (SMTP, Microsoft Graph, etc.).
+ * Implementations handle configuration loading and message sending.
+ */
+public interface EmailTransportProvider
+{
+    /**
+     * @return the display name of this provider for logging purposes
+     */
+    String getName();
+
+    /**
+     * Load configuration from startup properties and/or ServletContext.
+     * Called once during initialization.
+     */
+    void loadConfiguration();
+
+    /**
+     * @return true if this provider is fully configured and ready to send email
+     */
+    boolean isConfigured();
+
+    /**
+     * Send an email message using this transport.
+     *
+     * @param message the message to send
+     * @throws MessagingException if sending fails
+     */
+    void send(Message message) throws MessagingException;
+
+    /**
+     * @return the configuration properties for this provider
+     */
+    Properties getProperties();
+}