feat: Enhance Nodemailer transport with attachment support and raw message streaming

examples/nodemailer-transport.ts

@@ -16,7 +16,7 @@ async function nodemailerTransportExample() {
         apiKey: 'cebc9a7f-4e0c-4fda-9dd0-85f48c02800c',
         port: 80,
         secure: false, // Set to true for wss://
-        debug: false
+        debug: true
     });
 
     // Create Nodemailer transporter
@@ -51,7 +51,15 @@ async function nodemailerTransportExample() {
                     <li>Nodemailer compatibility</li>
                     <li>WebSocket-based SMTP relay</li>
                 </ul>
-            `
+                <p><strong>This email includes a test attachment!</strong></p>
+            `,
+            attachments: [
+                {
+                    filename: 'test-attachment.txt',
+                    content: Buffer.from(`This is a test attachment generated at ${new Date().toISOString()}\n\nRandom data: ${Math.random()}\nUUID: ${Date.now()}-${Math.random().toString(36).substr(2, 9)}\n\nFeatures tested:\n- File attachment support\n- Binary content handling\n- MIME multipart encoding\n- WebSocket SMTP transport\n\nEnd of test file.`, 'utf8'),
+                    contentType: 'text/plain'
+                }
+            ]
         });
 
         console.log('Email sent successfully!');

src/transport.ts

@@ -6,6 +6,7 @@ import { EventEmitter } from 'events';
 import { SMTPOverWSClient } from './client';
 import { SMTPClientConfig, ConnectionState } from './types';
 import { ConnectionError, MessageError, TimeoutError } from './errors';
+import { Readable } from 'stream';
 
 /**
  * Nodemailer transport interface compatibility
@@ -45,7 +46,8 @@ export interface MailMessage {
     data: any;
     message: {
         _envelope: Envelope;
-        _raw: string | Buffer;
+        _raw?: string | Buffer;
+        createReadStream(): Readable;
     };
     mailer: any;
 }
@@ -202,9 +204,11 @@ export class SMTPWSTransport extends EventEmitter {
      */
     private async sendMail(mail: MailMessage): Promise<SendResult> {
         const envelope = this.extractEnvelope(mail);
-        const raw = mail.message._raw;
         const messageId = this.generateMessageId();
 
+        // Get the raw message content from Nodemailer's stream
+        const rawMessage = await this.getRawMessage(mail);
+
         // Build complete SMTP transaction
         let smtpTransaction = '';
         
@@ -220,7 +224,7 @@ export class SMTPWSTransport extends EventEmitter {
         smtpTransaction += 'DATA\r\n';
         
         // Message content
-        const messageData = this.prepareMessageData(raw);
+        const messageData = this.prepareMessageData(rawMessage);
         smtpTransaction += messageData;
         
         // QUIT
@@ -337,6 +341,36 @@ export class SMTPWSTransport extends EventEmitter {
         return `smtp-ws-${Date.now()}-${Math.random().toString(36).substr(2, 9)}`;
     }
 
+    /**
+     * Get raw message content from Nodemailer mail object
+     */
+    private async getRawMessage(mail: MailMessage): Promise<string> {
+        return new Promise((resolve, reject) => {
+            // If raw message is already available, use it
+            if (mail.message._raw) {
+                resolve(mail.message._raw.toString());
+                return;
+            }
+
+            // Otherwise, stream the message from Nodemailer
+            const chunks: Buffer[] = [];
+            const stream = mail.message.createReadStream();
+            
+            stream.on('data', (chunk: Buffer) => {
+                chunks.push(chunk);
+            });
+            
+            stream.on('end', () => {
+                const rawMessage = Buffer.concat(chunks).toString();
+                resolve(rawMessage);
+            });
+            
+            stream.on('error', (error) => {
+                reject(new MessageError(`Failed to read message stream: ${error.message}`, 'stream-read', 0));
+            });
+        });
+    }
+
 }
 
 /**