Microsoft Outlook service root endpoint

This change makes the service root configurable for the Microsoft Outlook nodes.

The service root endpoint is configurable in the Outlook credential.

The motivation behind this change is to allow the Microsoft Outlook N8N node to connect to the other tenant types such as the Microsoft GovCloud instances.

packages/nodes-base/credentials/MicrosoftOutlookOAuth2Api.credentials.ts

@@ -15,6 +15,24 @@ const scopes = [
 	'MailboxSettings.Read',
 ];
 
+const enum EndpointNames {
+	Global = 'Microsoft Graph global service',
+	GovCloud = 'Microsoft Graph for US Government L4',
+	DoDCloud = 'Microsoft Graph for US Government L5 (DOD)',
+	China = 'Microsoft Graph China operated by 21Vianet',
+}
+
+/**
+ * The service endpoints are defined by Microsoft:
+ * https://learn.microsoft.com/en-us/graph/deployments#microsoft-graph-and-graph-explorer-service-root-endpoints
+ */
+const endpoints: Record<EndpointNames, string> = {
+	[EndpointNames.Global]: 'https://graph.microsoft.com',
+	[EndpointNames.GovCloud]: 'https://graph.microsoft.us',
+	[EndpointNames.DoDCloud]: 'https://dod-graph.microsoft.us',
+	[EndpointNames.China]: 'https://microsoftgraph.chinacloudapi.cn',
+};
+
 export class MicrosoftOutlookOAuth2Api implements ICredentialType {
 	name = 'microsoftOutlookOAuth2Api';
 
@@ -50,5 +68,16 @@ export class MicrosoftOutlookOAuth2Api implements ICredentialType {
 				},
 			},
 		},
+		{
+			displayName: 'Endpoint',
+			description: 'The service root endpoint to use when connecting to the Outlook API.',
+			name: 'graphEndpoint',
+			type: 'options',
+			default: endpoints[EndpointNames.Global],
+			options: Object.keys(endpoints).map((name) => ({
+				name,
+				value: endpoints[name as EndpointNames],
+			})),
+		},
 	];
 }

packages/nodes-base/nodes/Microsoft/Outlook/test/v2/transport/index.test.ts

@@ -0,0 +1,77 @@
+import type { ICredentialDataDecryptedObject, IExecuteFunctions } from 'n8n-workflow';
+
+import * as transport from '../../../v2/transport';
+
+const fakeExecute = (credentials: ICredentialDataDecryptedObject, result: unknown) => {
+	const fakeExecuteFunction = {
+		async getCredentials(): Promise<ICredentialDataDecryptedObject> {
+			return credentials;
+		},
+
+		helpers: {
+			requestWithAuthentication: jest.fn().mockResolvedValue(result),
+		},
+	} as unknown as IExecuteFunctions;
+	return fakeExecuteFunction;
+};
+
+describe('Test MicrosoftOutlookV2, transport => microsoftApiRequest', () => {
+	it('should call microsoftApiRequest using the defined service root', async () => {
+		const execute = fakeExecute(
+			{
+				graphEndpoint: 'https://foo.bar',
+				useShared: false,
+				userPrincipalName: 'test-principal',
+			},
+			'foo',
+		);
+
+		const result: string = (await transport.microsoftApiRequest.call(
+			execute,
+			'GET',
+			'/foo',
+		)) as string;
+
+		expect(result).toEqual('foo');
+		expect(execute.helpers.requestWithAuthentication).toHaveBeenCalledTimes(1);
+		expect(execute.helpers.requestWithAuthentication).toHaveBeenCalledWith(
+			'microsoftOutlookOAuth2Api',
+			{
+				headers: { 'Content-Type': 'application/json' },
+				method: 'GET',
+				qs: {},
+				uri: 'https://foo.bar/v1.0/me/foo',
+				json: true,
+			},
+		);
+	});
+
+	it('should call microsoftApiRequest using the service root if no root is provided', async () => {
+		const execute = fakeExecute(
+			{
+				useShared: false,
+				userPrincipalName: 'test-principal',
+			},
+			'foo',
+		);
+
+		const result: string = (await transport.microsoftApiRequest.call(
+			execute,
+			'GET',
+			'/foo',
+		)) as string;
+
+		expect(result).toEqual('foo');
+		expect(execute.helpers.requestWithAuthentication).toHaveBeenCalledTimes(1);
+		expect(execute.helpers.requestWithAuthentication).toHaveBeenCalledWith(
+			'microsoftOutlookOAuth2Api',
+			{
+				headers: { 'Content-Type': 'application/json' },
+				method: 'GET',
+				qs: {},
+				uri: 'https://graph.microsoft.com/v1.0/me/foo',
+				json: true,
+			},
+		);
+	});
+});

packages/nodes-base/nodes/Microsoft/Outlook/v2/transport/index.ts

@@ -22,11 +22,12 @@ export async function microsoftApiRequest(
 	option: IDataObject = { json: true },
 ) {
 	const credentials = await this.getCredentials('microsoftOutlookOAuth2Api');
+	const graphEndpoint = (credentials.graphEndpoint as string) || 'https://graph.microsoft.com';
 
-	let apiUrl = `https://graph.microsoft.com/v1.0/me${resource}`;
+	let apiUrl = `${graphEndpoint}/v1.0/me${resource}`;
 	// If accessing shared mailbox
 	if (credentials.useShared && credentials.userPrincipalName) {
-		apiUrl = `https://graph.microsoft.com/v1.0/users/${credentials.userPrincipalName}${resource}`;
+		apiUrl = `${graphEndpoint}/v1.0/users/${credentials.userPrincipalName}${resource}`;
 	}
 
 	const options: IRequestOptions = {