feat(n8nApi node): add core node for consuming the n8n API (n8n-io#4076)

* feat(n8n node): create n8n core node for consuming the n8n API

Co-authored-by: Michael Kret <michael.k@radency.com>

packages/nodes-base/credentials/N8nApi.credentials.ts

@@ -0,0 +1,43 @@
+import {
+	IAuthenticateGeneric,
+	ICredentialTestRequest,
+	ICredentialType,
+	INodeProperties,
+} from 'n8n-workflow';
+
+export class N8nApi implements ICredentialType {
+	name = 'n8nApi';
+	displayName = 'n8n API';
+	documentationUrl = 'n8nApi';
+	properties: INodeProperties[] = [
+		{
+			displayName: 'API Key',
+			name: 'apiKey',
+			type: 'string',
+			default: '',
+			description: 'The API key for the n8n instance',
+		},
+		{
+			displayName: 'Base URL',
+			name: 'baseUrl',
+			type: 'string',
+			default: '',
+			placeholder: 'https://<name>.app.n8n.cloud/api/v1',
+			description: 'The API URL of the n8n instance',
+		},
+	];
+	authenticate: IAuthenticateGeneric = {
+		type: 'generic',
+		properties: {
+			headers: {
+				'X-N8N-API-KEY': '={{ $credentials.apiKey }}',
+			},
+		},
+	};
+	test: ICredentialTestRequest = {
+		request: {
+			baseURL: '={{ $credentials.baseUrl }}',
+			url: '/workflows?limit=5',
+		},
+	};
+}

packages/nodes-base/nodes/N8n/CredentialDescription.ts

@@ -0,0 +1,168 @@
+import { INodeProperties } from 'n8n-workflow';
+import { parseAndSetBodyJson } from './GenericFunctions';
+
+export const credentialOperations: INodeProperties[] = [
+	{
+		displayName: 'Operation',
+		name: 'operation',
+		type: 'options',
+		noDataExpression: true,
+		default: 'create',
+		displayOptions: {
+			show: {
+				resource: ['credential'],
+			},
+		},
+		options: [
+			{
+				name: 'Create',
+				value: 'create',
+				action: 'Create a credential',
+				routing: {
+					request: {
+						method: 'POST',
+						url: '/credentials',
+					},
+				},
+			},
+			{
+				name: 'Delete',
+				value: 'delete',
+				action: 'Delete a credential',
+				routing: {
+					request: {
+						method: 'DELETE',
+						url: '=/credentials/{{ $parameter.credentialId }}',
+					},
+				},
+			},
+			{
+				name: 'Get Schema',
+				value: 'getSchema',
+				action: 'Get credential data schema for type',
+				routing: {
+					request: {
+						method: 'GET',
+						url: '=/credentials/schema/{{ $parameter.credentialTypeName }}',
+					},
+				},
+			},
+		],
+	},
+];
+
+const createOperation: INodeProperties[] = [
+	{
+		displayName: 'Name',
+		name: 'name',
+		type: 'string',
+		default: '',
+		placeholder: 'e.g. n8n account',
+		required: true,
+		displayOptions: {
+			show: {
+				resource: ['credential'],
+				operation: ['create'],
+			},
+		},
+		routing: {
+			request: {
+				body: {
+					name: '={{ $value }}',
+				},
+			},
+		},
+		description: 'Name of the new credential',
+	},
+	{
+		displayName: 'Credential Type',
+		name: 'credentialTypeName',
+		type: 'string',
+		placeholder: 'e.g. n8nApi',
+		default: '',
+		required: true,
+		displayOptions: {
+			show: {
+				resource: ['credential'],
+				operation: ['create'],
+			},
+		},
+		routing: {
+			request: {
+				body: {
+					type: '={{ $value }}',
+				},
+			},
+		},
+		description:
+			"The available types depend on nodes installed on the n8n instance. Some built-in types include e.g. 'githubApi', 'notionApi', and 'slackApi'.",
+	},
+	{
+		displayName: 'Data',
+		name: 'data',
+		type: 'json',
+		default: '',
+		placeholder:
+			'// e.g. for n8nApi \n{\n  "apiKey": "my-n8n-api-key",\n  "baseUrl": "https://<name>.app.n8n.cloud/api/v1",\n}',
+		required: true,
+		typeOptions: {
+			alwaysOpenEditWindow: true,
+		},
+		displayOptions: {
+			show: {
+				resource: ['credential'],
+				operation: ['create'],
+			},
+		},
+		routing: {
+			send: {
+				// Validate that the 'data' property is parseable as JSON and
+				// set it into the request as body.data.
+				preSend: [parseAndSetBodyJson('data', 'data')],
+			},
+		},
+		description:
+			"A valid JSON object with properties required for this Credential Type. To see the expected format, you can use 'Get Schema' operation.",
+	},
+];
+
+const deleteOperation: INodeProperties[] = [
+	{
+		displayName: 'Credential ID',
+		name: 'credentialId',
+		type: 'string',
+		required: true,
+		default: '',
+		displayOptions: {
+			show: {
+				resource: ['credential'],
+				operation: ['delete'],
+			},
+		},
+	},
+];
+
+const getSchemaOperation: INodeProperties[] = [
+	{
+		displayName: 'Credential Type',
+		name: 'credentialTypeName',
+		default: '',
+		placeholder: 'e.g. n8nApi',
+		required: true,
+		type: 'string',
+		displayOptions: {
+			show: {
+				resource: ['credential'],
+				operation: ['getSchema'],
+			},
+		},
+		description:
+			"The available types depend on nodes installed on the n8n instance. Some built-in types include e.g. 'githubApi', 'notionApi', and 'slackApi'.",
+	},
+];
+
+export const credentialFields: INodeProperties[] = [
+	...createOperation,
+	...deleteOperation,
+	...getSchemaOperation,
+];