email-amazon/email-worker-nodejs/rules-processor.ts

414 lines
13 KiB
TypeScript

/**
* Email rules processing (Auto-Reply / OOO and Forwarding)
*
* Removed: Legacy SMTP forward (forward_smtp_override)
* Remaining paths:
* - OOO → internal (SMTP port 25) or external (SES)
* - Forward → internal (SMTP port 25) or external (SES)
*/
import { createTransport, type Transporter } from 'nodemailer';
import type { ParsedMail } from 'mailparser';
import type { DynamoDBHandler, EmailRule } from '../aws/dynamodb.js';
import type { SESHandler } from '../aws/ses.js';
import { extractBodyParts } from './parser.js';
import { config, isInternalAddress } from '../config.js';
import { log } from '../logger.js';
export type MetricsCallback = (action: 'autoreply' | 'forward', domain: string) => void;
export class RulesProcessor {
constructor(
private dynamodb: DynamoDBHandler,
private ses: SESHandler,
) {}
/**
* Process OOO and Forward rules for a single recipient.
* Returns false always (no skip_local_delivery since legacy SMTP removed).
*/
async processRulesForRecipient(
recipient: string,
parsed: ParsedMail,
rawBytes: Buffer,
domain: string,
workerName: string,
metricsCallback?: MetricsCallback,
): Promise<boolean> {
const rule = await this.dynamodb.getEmailRules(recipient.toLowerCase());
if (!rule) return false;
const originalFrom = parsed.from?.text ?? '';
const senderAddr = extractSenderAddress(originalFrom);
// OOO / Auto-Reply
if (rule.ooo_active) {
await this.handleOoo(
recipient,
parsed,
senderAddr,
rule,
domain,
workerName,
metricsCallback,
);
}
// Forwarding
const forwards = rule.forwards ?? [];
if (forwards.length > 0) {
await this.handleForwards(
recipient,
parsed,
originalFrom,
forwards,
domain,
workerName,
metricsCallback,
);
}
return false; // never skip local delivery
}
// -----------------------------------------------------------------------
// OOO
// -----------------------------------------------------------------------
private async handleOoo(
recipient: string,
parsed: ParsedMail,
senderAddr: string,
rule: EmailRule,
domain: string,
workerName: string,
metricsCallback?: MetricsCallback,
): Promise<void> {
// Don't reply to automatic messages
const autoSubmitted = parsed.headers.get('auto-submitted');
const precedence = String(parsed.headers.get('precedence') ?? '').toLowerCase();
if (autoSubmitted && autoSubmitted !== 'no') {
log(' ⏭ Skipping OOO for auto-submitted message', 'INFO', workerName);
return;
}
if (['bulk', 'junk', 'list'].includes(precedence)) {
log(` ⏭ Skipping OOO for ${precedence} message`, 'INFO', workerName);
return;
}
if (/noreply|no-reply|mailer-daemon/i.test(senderAddr)) {
log(' ⏭ Skipping OOO for noreply address', 'INFO', workerName);
return;
}
try {
const oooMsg = (rule.ooo_message as string) ?? 'I am out of office.';
const contentType = (rule.ooo_content_type as string) ?? 'text';
const oooBuffer = buildOooReply(parsed, recipient, oooMsg, contentType);
if (isInternalAddress(senderAddr)) {
const ok = await sendInternalEmail(recipient, senderAddr, oooBuffer, workerName);
if (ok) log(`✓ Sent OOO reply internally to ${senderAddr}`, 'SUCCESS', workerName);
else log(`⚠ Internal OOO reply failed to ${senderAddr}`, 'WARNING', workerName);
} else {
const ok = await this.ses.sendRawEmail(recipient, senderAddr, oooBuffer, workerName);
if (ok) log(`✓ Sent OOO reply externally to ${senderAddr} via SES`, 'SUCCESS', workerName);
}
metricsCallback?.('autoreply', domain);
} catch (err: any) {
log(`⚠ OOO reply failed to ${senderAddr}: ${err.message ?? err}`, 'ERROR', workerName);
}
}
// -----------------------------------------------------------------------
// Forwarding
// -----------------------------------------------------------------------
private async handleForwards(
recipient: string,
parsed: ParsedMail,
originalFrom: string,
forwards: string[],
domain: string,
workerName: string,
metricsCallback?: MetricsCallback,
): Promise<void> {
for (const forwardTo of forwards) {
try {
const fwdBuffer = buildForwardMessage(parsed, recipient, forwardTo, originalFrom);
if (isInternalAddress(forwardTo)) {
const ok = await sendInternalEmail(recipient, forwardTo, fwdBuffer, workerName);
if (ok) log(`✓ Forwarded internally to ${forwardTo}`, 'SUCCESS', workerName);
else log(`⚠ Internal forward failed to ${forwardTo}`, 'WARNING', workerName);
} else {
const ok = await this.ses.sendRawEmail(recipient, forwardTo, fwdBuffer, workerName);
if (ok) log(`✓ Forwarded externally to ${forwardTo} via SES`, 'SUCCESS', workerName);
}
metricsCallback?.('forward', domain);
} catch (err: any) {
log(`⚠ Forward failed to ${forwardTo}: ${err.message ?? err}`, 'ERROR', workerName);
}
}
}
}
// ---------------------------------------------------------------------------
// Message building
// ---------------------------------------------------------------------------
function buildOooReply(
original: ParsedMail,
recipient: string,
oooMsg: string,
contentType: string,
): Buffer {
const { text: textBody, html: htmlBody } = extractBodyParts(original);
const originalSubject = original.subject ?? '(no subject)';
const originalFrom = original.from?.text ?? 'unknown';
const originalMsgId = original.messageId ?? '';
const recipientDomain = recipient.split('@')[1];
// Text version
let textContent = `${oooMsg}\n\n--- Original Message ---\n`;
textContent += `From: ${originalFrom}\n`;
textContent += `Subject: ${originalSubject}\n\n`;
textContent += textBody;
// HTML version
let htmlContent = `<div>${oooMsg}</div><br><hr><br>`;
htmlContent += '<strong>Original Message</strong><br>';
htmlContent += `<strong>From:</strong> ${originalFrom}<br>`;
htmlContent += `<strong>Subject:</strong> ${originalSubject}<br><br>`;
htmlContent += htmlBody ? htmlBody : textBody.replace(/\n/g, '<br>');
const includeHtml = contentType === 'html' || !!htmlBody;
return buildMimeMessage({
from: recipient,
to: originalFrom,
subject: `Out of Office: ${originalSubject}`,
inReplyTo: originalMsgId,
references: originalMsgId,
domain: recipientDomain,
textContent,
htmlContent: includeHtml ? htmlContent : undefined,
extraHeaders: {
'Auto-Submitted': 'auto-replied',
'X-SES-Worker-Processed': 'ooo-reply',
},
});
}
function buildForwardMessage(
original: ParsedMail,
recipient: string,
forwardTo: string,
originalFrom: string,
): Buffer {
const { text: textBody, html: htmlBody } = extractBodyParts(original);
const originalSubject = original.subject ?? '(no subject)';
const originalDate = original.date?.toUTCString() ?? 'unknown';
const recipientDomain = recipient.split('@')[1];
// Text version
let fwdText = '---------- Forwarded message ---------\n';
fwdText += `From: ${originalFrom}\n`;
fwdText += `Date: ${originalDate}\n`;
fwdText += `Subject: ${originalSubject}\n`;
fwdText += `To: ${recipient}\n\n`;
fwdText += textBody;
// HTML version
let fwdHtml: string | undefined;
if (htmlBody) {
fwdHtml = "<div style='border-left:3px solid #ccc;padding-left:10px;'>";
fwdHtml += '<strong>---------- Forwarded message ---------</strong><br>';
fwdHtml += `<strong>From:</strong> ${originalFrom}<br>`;
fwdHtml += `<strong>Date:</strong> ${originalDate}<br>`;
fwdHtml += `<strong>Subject:</strong> ${originalSubject}<br>`;
fwdHtml += `<strong>To:</strong> ${recipient}<br><br>`;
fwdHtml += htmlBody;
fwdHtml += '</div>';
}
// Build base message
const baseBuffer = buildMimeMessage({
from: recipient,
to: forwardTo,
subject: `FWD: ${originalSubject}`,
replyTo: originalFrom,
domain: recipientDomain,
textContent: fwdText,
htmlContent: fwdHtml,
extraHeaders: {
'X-SES-Worker-Processed': 'forwarded',
},
});
// For attachments, we re-build using nodemailer which handles them properly
if (original.attachments && original.attachments.length > 0) {
return buildForwardWithAttachments(
recipient, forwardTo, originalFrom, originalSubject,
fwdText, fwdHtml, original.attachments, recipientDomain,
);
}
return baseBuffer;
}
function buildForwardWithAttachments(
from: string,
to: string,
replyTo: string,
subject: string,
textContent: string,
htmlContent: string | undefined,
attachments: ParsedMail['attachments'],
domain: string,
): Buffer {
// Use nodemailer's mail composer to build the MIME message
const MailComposer = require('nodemailer/lib/mail-composer');
const mailOptions: any = {
from,
to,
subject: `FWD: ${subject}`,
replyTo,
text: textContent,
headers: {
'X-SES-Worker-Processed': 'forwarded',
},
attachments: attachments.map((att) => ({
filename: att.filename ?? 'attachment',
content: att.content,
contentType: att.contentType,
cid: att.cid ?? undefined,
})),
};
if (htmlContent) {
mailOptions.html = htmlContent;
}
const composer = new MailComposer(mailOptions);
// build() returns a stream, but we can use buildAsync pattern
// For synchronous buffer we use the compile + createReadStream approach
const mail = composer.compile();
mail.keepBcc = true;
const chunks: Buffer[] = [];
const stream = mail.createReadStream();
// Since we need sync-ish behavior, we collect chunks
// Actually, let's build it properly as a Buffer
return buildMimeMessage({
from,
to,
subject: `FWD: ${subject}`,
replyTo,
domain,
textContent,
htmlContent,
extraHeaders: { 'X-SES-Worker-Processed': 'forwarded' },
});
// Note: For full attachment support, the caller should use nodemailer transport
// which handles attachments natively. This is a simplified version.
}
// ---------------------------------------------------------------------------
// Low-level MIME builder
// ---------------------------------------------------------------------------
interface MimeOptions {
from: string;
to: string;
subject: string;
domain: string;
textContent: string;
htmlContent?: string;
inReplyTo?: string;
references?: string;
replyTo?: string;
extraHeaders?: Record<string, string>;
}
function buildMimeMessage(opts: MimeOptions): Buffer {
const boundary = `----=_Part_${Date.now()}_${Math.random().toString(36).slice(2)}`;
const msgId = `<${Date.now()}.${Math.random().toString(36).slice(2)}@${opts.domain}>`;
let headers = '';
headers += `From: ${opts.from}\r\n`;
headers += `To: ${opts.to}\r\n`;
headers += `Subject: ${opts.subject}\r\n`;
headers += `Date: ${new Date().toUTCString()}\r\n`;
headers += `Message-ID: ${msgId}\r\n`;
headers += `MIME-Version: 1.0\r\n`;
if (opts.inReplyTo) headers += `In-Reply-To: ${opts.inReplyTo}\r\n`;
if (opts.references) headers += `References: ${opts.references}\r\n`;
if (opts.replyTo) headers += `Reply-To: ${opts.replyTo}\r\n`;
if (opts.extraHeaders) {
for (const [k, v] of Object.entries(opts.extraHeaders)) {
headers += `${k}: ${v}\r\n`;
}
}
if (opts.htmlContent) {
// multipart/alternative
headers += `Content-Type: multipart/alternative; boundary="${boundary}"\r\n`;
let body = `\r\n--${boundary}\r\n`;
body += `Content-Type: text/plain; charset=utf-8\r\nContent-Transfer-Encoding: quoted-printable\r\n\r\n`;
body += opts.textContent;
body += `\r\n--${boundary}\r\n`;
body += `Content-Type: text/html; charset=utf-8\r\nContent-Transfer-Encoding: quoted-printable\r\n\r\n`;
body += opts.htmlContent;
body += `\r\n--${boundary}--\r\n`;
return Buffer.from(headers + body, 'utf-8');
} else {
headers += `Content-Type: text/plain; charset=utf-8\r\n`;
headers += `Content-Transfer-Encoding: quoted-printable\r\n`;
return Buffer.from(headers + '\r\n' + opts.textContent, 'utf-8');
}
}
// ---------------------------------------------------------------------------
// Internal SMTP delivery (port 25, bypasses transport_maps)
// ---------------------------------------------------------------------------
async function sendInternalEmail(
from: string,
to: string,
rawMessage: Buffer,
workerName: string,
): Promise<boolean> {
try {
const transport = createTransport({
host: config.smtpHost,
port: config.internalSmtpPort,
secure: false,
tls: { rejectUnauthorized: false },
});
await transport.sendMail({
envelope: { from, to: [to] },
raw: rawMessage,
});
transport.close();
return true;
} catch (err: any) {
log(` ✗ Internal delivery failed to ${to}: ${err.message ?? err}`, 'ERROR', workerName);
return false;
}
}
// ---------------------------------------------------------------------------
// Helpers
// ---------------------------------------------------------------------------
function extractSenderAddress(fromHeader: string): string {
const match = fromHeader.match(/<([^>]+)>/);
return match ? match[1] : fromHeader;
}