module smtp /* * * smtp module * Created by: nedimf (07/2020) */ import net import encoding.base64 import strings import time import io const ( recv_size = 128 ) enum ReplyCode { ready = 220 close = 221 auth_ok = 235 action_ok = 250 mail_start = 354 } pub enum BodyType { text html } pub struct Client { mut: conn net.TcpConn reader io.BufferedReader pub: server string port int = 25 username string password string from string pub mut: is_open bool } pub struct Mail { from string to string cc string bcc string date time.Time = time.now() subject string body_type BodyType body string } // new_client returns a new SMTP client and connects to it pub fn new_client(config Client) ?&Client { mut c := &Client{ ...config } c.reconnect() ? return c } // reconnect reconnects to the SMTP server if the connection was closed pub fn (mut c Client) reconnect() ? { if c.is_open { return error('Already connected to server') } conn := net.dial_tcp('$c.server:$c.port') or { return error('Connecting to server failed') } c.conn = conn c.reader = io.new_buffered_reader(reader: io.make_reader(c.conn)) c.expect_reply(.ready) or { return error('Received invalid response from server') } c.send_ehlo() or { return error('Sending EHLO packet failed') } c.send_auth() or { return error('Authenticating to server failed') } c.is_open = true } // send sends an email pub fn (mut c Client) send(config Mail) ? { if !c.is_open { return error('Disconnected from server') } from := if config.from != '' { config.from } else { c.from } c.send_mailfrom(from) or { return error('Sending mailfrom failed') } c.send_mailto(config.to) or { return error('Sending mailto failed') } c.send_data() or { return error('Sending mail data failed') } c.send_body({ config | from: from }) or { return error('Sending mail body failed') } } // quit closes the connection to the server pub fn (mut c Client) quit() ? { c.send_str('QUIT\r\n') c.expect_reply(.close) c.conn.close() ? c.is_open = false } // expect_reply checks if the SMTP server replied with the expected reply code fn (mut c Client) expect_reply(expected ReplyCode) ? { bytes := io.read_all(reader: c.conn) ? str := bytes.bytestr().trim_space() $if smtp_debug ? { eprintln('\n\n[RECV]') eprint(str) } if str.len >= 3 { status := str[..3].int() if ReplyCode(status) != expected { return error('Received unexpected status code $status, expecting $expected') } } else { return error('Recieved unexpected SMTP data: $str') } } [inline] fn (mut c Client) send_str(s string) ? { $if smtp_debug ? { eprintln('\n\n[SEND START]') eprint(s.trim_space()) eprintln('\n[SEND END]') } c.conn.write(s.bytes()) ? } [inline] fn (mut c Client) send_ehlo() ? { c.send_str('EHLO $c.server\r\n') ? c.expect_reply(.action_ok) ? } [inline] fn (mut c Client) send_auth() ? { if c.username.len == 0 { return } mut sb := strings.new_builder(100) sb.write_b(0) sb.write(c.username) sb.write_b(0) sb.write(c.password) a := sb.str() auth := 'AUTH PLAIN ${base64.encode(a)}\r\n' c.send_str(auth) ? c.expect_reply(.auth_ok) ? } fn (mut c Client) send_mailfrom(from string) ? { c.send_str('MAIL FROM: <$from>\r\n') ? c.expect_reply(.action_ok) ? } fn (mut c Client) send_mailto(to string) ? { c.send_str('RCPT TO: <$to>\r\n') ? c.expect_reply(.action_ok) ? } fn (mut c Client) send_data() ? { c.send_str('DATA\r\n') ? c.expect_reply(.mail_start) } fn (mut c Client) send_body(cfg Mail) ? { is_html := cfg.body_type == .html date := cfg.date.utc_string().trim_right(' UTC') // TODO mut sb := strings.new_builder(200) sb.write('From: $cfg.from\r\n') sb.write('To: <$cfg.to>\r\n') sb.write('Cc: <$cfg.cc>\r\n') sb.write('Bcc: <$cfg.bcc>\r\n') sb.write('Date: $date\r\n') sb.write('Subject: $cfg.subject\r\n') if is_html { sb.write('Content-Type: text/html; charset=ISO-8859-1') } sb.write('\r\n\r\n') sb.write(cfg.body) sb.write('\r\n.\r\n') c.send_str(sb.str()) ? c.expect_reply(.action_ok) ? }