fix(Email Trigger (IMAP) Node): Handle gb2312 encoding correctly

packages/@n8n/imap/src/ImapSimple.ts

@@ -136,7 +136,7 @@ export class ImapSimple extends EventEmitter {
 
 				const data = result.parts[0].body as string;
 				const encoding = part.encoding.toUpperCase();
-				resolve(PartData.fromData(data, encoding));
+				resolve(PartData.fromData(data, encoding, part.params?.charset));
 			};
 
 			const fetchOnError = (error: Error) => {

packages/@n8n/imap/src/PartData.ts

@@ -7,8 +7,8 @@ import * as uuencode from 'uuencode';
 export abstract class PartData {
 	constructor(readonly buffer: Buffer) {}
 
-	toString() {
-		return this.buffer.toString();
+	toString(charset?: string) {
+		return iconvlite.decode(this.buffer, charset ?? 'utf-8');
 	}
 
 	static fromData(data: string, encoding: string, charset?: string): PartData {
@@ -44,10 +44,25 @@ export class Base64PartData extends PartData {
 }
 
 export class QuotedPrintablePartData extends PartData {
+	static ansiBuffer(data: string): Buffer {
+		const decoded = qp.decode(data);
+		const arr = [];
+		for (let index = 0; index < decoded.length; index++) {
+			arr.push(decoded.charCodeAt(index));
+		}
+		return Buffer.from(arr);
+	}
+
+	static utf8Buffer(data: string): Buffer {
+		return Buffer.from(utf8.decode(qp.decode(data)));
+	}
+
 	constructor(data: string, charset?: string) {
 		const decoded =
-			charset?.toUpperCase() === 'UTF-8' ? utf8.decode(qp.decode(data)) : qp.decode(data);
-		super(Buffer.from(decoded));
+			charset?.toUpperCase() === 'UTF-8'
+				? QuotedPrintablePartData.utf8Buffer(data)
+				: QuotedPrintablePartData.ansiBuffer(data);
+		super(decoded);
 	}
 }
 

packages/@n8n/imap/test/PartData.test.ts

@@ -60,6 +60,14 @@ describe('QuotedPrintablePartData', () => {
 	});
 });
 
+describe('QuotedPrintableGB2312PartData', () => {
+	it('should correctly decode quoted-printable data', () => {
+		const data = '=C4=E3=BA=C3=A3=AC =CA=C0=BD=E7=A3=A1'; // '你好， 世界！' in quoted-printable with gb2312 encoding
+		const partData = new QuotedPrintablePartData(data, 'gb2312');
+		expect(partData.toString('gb2312')).toBe('你好， 世界！');
+	});
+});
+
 describe('SevenBitPartData', () => {
 	it('should correctly decode 7bit data', () => {
 		const data = 'Hello, world!';

packages/nodes-base/nodes/EmailReadImap/v2/EmailReadImapV2.node.ts

@@ -321,7 +321,7 @@ export class EmailReadImapV2 implements INodeType {
 
 			try {
 				const partData = await connection.getPartData(message, part);
-				return partData.toString();
+				return partData.toString(part.params?.charset);
 			} catch {
 				return '';
 			}