feat(Postgres Chat Memory Node): Implement Postgres Chat Memory node (#10071)

packages/@n8n/nodes-langchain/nodes/memory/MemoryPostgresChat/MemoryPostgresChat.node.ts

@@ -0,0 +1,103 @@
+/* eslint-disable n8n-nodes-base/node-dirname-against-convention */
+import type { IExecuteFunctions, INodeType, INodeTypeDescription, SupplyData } from 'n8n-workflow';
+import { NodeConnectionType } from 'n8n-workflow';
+import { BufferMemory } from 'langchain/memory';
+import { PostgresChatMessageHistory } from '@langchain/community/stores/message/postgres';
+import type pg from 'pg';
+import { configurePostgres } from 'n8n-nodes-base/dist/nodes/Postgres/v2/transport';
+import type { PostgresNodeCredentials } from 'n8n-nodes-base/dist/nodes/Postgres/v2/helpers/interfaces';
+import { postgresConnectionTest } from 'n8n-nodes-base/dist/nodes/Postgres/v2/methods/credentialTest';
+import { logWrapper } from '../../../utils/logWrapper';
+import { getConnectionHintNoticeField } from '../../../utils/sharedFields';
+import { sessionIdOption, sessionKeyProperty } from '../descriptions';
+import { getSessionId } from '../../../utils/helpers';
+
+export class MemoryPostgresChat implements INodeType {
+	description: INodeTypeDescription = {
+		displayName: 'Postgres Chat Memory',
+		name: 'memoryPostgresChat',
+		icon: 'file:postgres.svg',
+		group: ['transform'],
+		version: [1],
+		description: 'Stores the chat history in Postgres table.',
+		defaults: {
+			name: 'Postgres Chat Memory',
+		},
+		credentials: [
+			{
+				name: 'postgres',
+				required: true,
+				testedBy: 'postgresConnectionTest',
+			},
+		],
+		codex: {
+			categories: ['AI'],
+			subcategories: {
+				AI: ['Memory'],
+			},
+			resources: {
+				primaryDocumentation: [
+					{
+						url: 'https://docs.n8n.io/integrations/builtin/cluster-nodes/sub-nodes/n8n-nodes-langchain.memorypostgreschat/',
+					},
+				],
+			},
+		},
+		// eslint-disable-next-line n8n-nodes-base/node-class-description-inputs-wrong-regular-node
+		inputs: [],
+		// eslint-disable-next-line n8n-nodes-base/node-class-description-outputs-wrong
+		outputs: [NodeConnectionType.AiMemory],
+		outputNames: ['Memory'],
+		properties: [
+			getConnectionHintNoticeField([NodeConnectionType.AiAgent]),
+			sessionIdOption,
+			sessionKeyProperty,
+			{
+				displayName: 'Table Name',
+				name: 'tableName',
+				type: 'string',
+				default: 'n8n_chat_histories',
+				description:
+					'The table name to store the chat history in. If table does not exist, it will be created.',
+			},
+		],
+	};
+
+	methods = {
+		credentialTest: {
+			postgresConnectionTest,
+		},
+	};
+
+	async supplyData(this: IExecuteFunctions, itemIndex: number): Promise<SupplyData> {
+		const credentials = (await this.getCredentials('postgres')) as PostgresNodeCredentials;
+		const tableName = this.getNodeParameter('tableName', itemIndex, 'n8n_chat_histories') as string;
+		const sessionId = getSessionId(this, itemIndex);
+
+		const pgConf = await configurePostgres.call(this, credentials);
+		const pool = pgConf.db.$pool as unknown as pg.Pool;
+
+		const pgChatHistory = new PostgresChatMessageHistory({
+			pool,
+			sessionId,
+			tableName,
+		});
+
+		const memory = new BufferMemory({
+			memoryKey: 'chat_history',
+			chatHistory: pgChatHistory,
+			returnMessages: true,
+			inputKey: 'input',
+			outputKey: 'output',
+		});
+
+		async function closeFunction() {
+			void pool.end();
+		}
+
+		return {
+			closeFunction,
+			response: logWrapper(memory, this),
+		};
+	}
+}