wildduck/lmtp.js

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5.6 KiB
JavaScript
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2017-03-06 22:13:40 +08:00
'use strict';
const config = require('config');
const log = require('npmlog');
const SMTPServer = require('smtp-server').SMTPServer;
const mongodb = require('mongodb');
const MongoClient = mongodb.MongoClient;
const crypto = require('crypto');
const punycode = require('punycode');
let imapServer;
let database;
const server = new SMTPServer({
// log to console
logger: {
info(...args) {
args.shift();
log.info('LMTP', ...args);
},
debug(...args) {
args.shift();
log.silly('LMTP', ...args);
},
error(...args) {
args.shift();
log.error('LMTP', ...args);
}
},
name: false,
lmtp: true,
// not required but nice-to-have
banner: 'Welcome to Wild Duck Mail Agent',
// disable STARTTLS to allow authentication in clear text mode
disabledCommands: ['AUTH', 'STARTTLS'],
// Accept messages up to 10 MB
size: config.lmtp.maxMB * 1024 * 1024,
// Validate RCPT TO envelope address. Example allows all addresses that do not start with 'deny'
// If this method is not set, all addresses are allowed
onRcptTo(address, session, callback) {
let username = normalizeAddress(address.address);
database.collection('users').findOne({
username
}, (err, user) => {
if (err) {
log.error('LMTP', err);
return callback(new Error('Database error'));
}
if (!user) {
return callback(new Error('Unknown recipient'));
}
if (!session.users) {
session.users = new Set();
}
session.users.add(username);
callback();
});
},
// Handle message stream
onData(stream, session, callback) {
let chunks = [];
let chunklen = 0;
let hash = crypto.createHash('md5');
stream.on('readable', () => {
let chunk;
while ((chunk = stream.read()) !== null) {
chunks.push(chunk);
chunklen += chunk.length;
hash.update(chunk);
}
});
stream.once('error', err => {
log.error('LMTP', err);
callback(new Error('Error reading from stream'));
});
stream.once('end', () => {
let err;
if (stream.sizeExceeded) {
err = new Error('Error: message exceeds fixed maximum message size ' + config.lmtp.maxMB + ' MB');
err.responseCode = 552;
return callback(err);
}
if (!session.users || !session.users.size) {
return callback(new Error('Nowhere to save the mail to'));
}
let users = Array.from(session.users);
let stored = 0;
let storeNext = () => {
if (stored >= users.length) {
return callback(null, 'Message queued as ' + hash.digest('hex').toUpperCase());
}
let username = users[stored++];
// add Delivered-To
let header = Buffer.from('Delivered-To: ' + username + '\r\n');
chunks.unshift(header);
chunklen += header.length;
imapServer.addToMailbox(username, 'INBOX', {
source: 'LMTP',
from: normalizeAddress(session.envelope.mailFrom && session.envelope.mailFrom.address || ''),
to: session.envelope.rcptTo.map(item => normalizeAddress(item.address)),
origin: session.remoteAddress,
originhost: session.clientHostname,
transhost: session.hostNameAppearsAs,
transtype: session.transmissionType,
time: Date.now()
}, false, [], Buffer.concat(chunks, chunklen), err => {
// remove Delivered-To
chunks.shift();
chunklen -= header.length;
if (err) {
log.error('LMTP', err);
}
storeNext();
});
};
storeNext();
});
}
});
function normalizeAddress(address, withNames) {
if (typeof address === 'string') {
address = {
address
};
}
if (!address || !address.address) {
return '';
}
let user = address.address.substr(0, address.address.lastIndexOf('@'));
let domain = address.address.substr(address.address.lastIndexOf('@') + 1);
let addr = user.trim() + '@' + punycode.toASCII(domain.toLowerCase().trim());
if (withNames) {
return {
name: address.name || '',
address: addr
};
}
return addr;
}
module.exports = (imap, done) => {
if (!config.lmtp.enabled) {
return setImmediate(() => done(null, false));
}
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MongoClient.connect(config.mongo, (err, mongo) => {
if (err) {
log.error('LMTP', 'Could not initialize MongoDB: %s', err.message);
return;
}
database = mongo;
imapServer = imap;
let started = false;
server.on('error', err => {
if (!started) {
started = true;
return done(err);
}
log.error('LMTP', err);
});
server.listen(config.lmtp.port, config.lmtp.host, () => {
if (started) {
return server.close();
}
started = true;
done(null, server);
});
});
};