net: implementation of SMTP RFC 2821 (#5807)

vlib/net/smtp/smtp.v

@@ -0,0 +1,216 @@
+module smtp
+
+/*
+*
+* smtp module 
+* Created by: nedimf (07/2020)
+*/
+import net
+import encoding.base64
+import strings
+
+struct Commands {
+	ehlo       string = 'EHLO Alice\r\n'
+	auth_plain string = 'AUTH PLAIN '
+	mail_from  string = 'MAIL FROM:'
+	recpt_to   string = 'RCPT TO:'
+	data       string = 'DATA\r\n'
+	subject    string = 'Subject:'
+	end_msg    string = '\r\n.\r\n'
+	quit       string = 'QUIT\r\n'
+}
+
+
+// Sends an email trough SMTP socket
+pub fn send_mail(mailserver string, port int, username, password, subject, from, to, body, type_body string, debug bool)? {
+	client := connect(mailserver, port, debug)?
+	send_ehlo(client, debug)
+	auth(client, username, password, debug)
+	send_mailfrom(client, from, debug)
+	send_mailto(client, to, debug)
+	send_data(client, debug)
+	if type_body == 'html' {
+		send_html_body(client, subject, from, to, body, debug)
+	} else {
+		send_text_body(client, subject, from, to, body, debug)
+	}
+	send_quit(client, debug)
+}
+
+// Creates socket connection with TCP server on provided port and returns net.Socket
+pub fn connect(mailserver string, port int, debug bool) ?(net.Socket) {
+	mut client := net.dial(mailserver, port)?
+	bytes, blen := client.recv(1024)
+	recv := recieved(bytes, blen)
+	if recv.len >= 3 {
+		is_debug(debug, recv)
+		status := recv[..3]
+		if status.int() != 220 {
+			return error('Replay (220) from server has not been recieved.\nReplay recieved: $status')
+		}
+	} else {
+		return error('Recieved data from SMTP server is not returning supported values\nReturned values: $recv')
+	}
+	return client
+}
+
+// Sends EHLO command to connected server. EHLO (Extended HELO) tells mailserver that our connection uses ESMTP
+pub fn send_ehlo(socket net.Socket, debug bool) ?bool {
+	cmd := Commands{}
+	recv := send(socket, cmd.ehlo)
+	if recv.len >= 3 {
+		status := recv[..3]
+		is_debug(debug, recv)
+		if status.int() != 250 {
+			return error('Replay (250) from server has not been recieved for EHLO.\nReplay recieved: $status')
+		}
+	} else {
+		return error('Recieved data from SMTP server is not returning supported values\nReturned values: $recv')
+	}
+	return true
+}
+
+// Closing the connection with server
+pub fn send_quit(socket net.Socket, debug bool) ?bool {
+	cmd := Commands{}
+	recv := send(socket, cmd.quit)
+	if recv.len >= 3 {
+		status := recv[..3]
+		is_debug(debug, recv)
+		if status.int() != 221 {
+			return error('Replay (221) from server has not been recieved for QUIT.\nReplay recieved: $status')
+		}
+	} else {
+		return error('Recieved data from SMTP server is not returning supported values\nReturned values: $recv')
+	}
+	return true
+}
+
+fn send_mailfrom(socket net.Socket, from string, debug bool) ?bool {
+	cmd := Commands{}
+	recv := send(socket, cmd.mail_from + ' <$from>\r\n')
+	if recv.len >= 3 {
+		status := recv[..3]
+		is_debug(debug, recv)
+		if status.int() != 221 {
+			return error('Replay (221) from server has not been recieved for MAIL FROM.\nReplay recieved: $status')
+		}
+	} else {
+		return error('Recieved data from SMTP server is not returning supported values\nReturned values: $recv')
+	}
+	return true
+}
+
+fn send_mailto(socket net.Socket, to string, debug bool) ?bool {
+	cmd := Commands{}
+	recv := send(socket, cmd.recpt_to + ' <$to>\r\n')
+	if recv.len >= 3 {
+		status := recv[..3]
+		is_debug(debug, recv)
+		if status.int() != 221 {
+			return error('Replay (221) from server has not been recieved for MAIL TO.\nReplay recieved: $status')
+		}
+	} else {
+		return error('Recieved data from SMTP server is not returning supported values\nReturned values: $recv')
+	}
+	return true
+}
+
+fn send_data(socket net.Socket, debug bool) ?bool {
+	cmd := Commands{}
+	recv := send(socket, cmd.data)
+	if recv.len >= 3 {
+		status := recv[..3]
+		is_debug(debug, recv)
+		if status.int() != 354 {
+			return error('Replay (354) from server has not been recieved for DATA.\nReplay recieved: $status')
+		}
+	} else {
+		return error('Recieved data from SMTP server is not returning supported values\nReturned values: $recv')
+	}
+	return true
+}
+
+fn send(socket net.Socket, string_to_send string) string {
+	socket.send_string(string_to_send)
+	bytes, blen := socket.recv(1024)
+	return recieved(bytes, blen)
+}
+
+fn send_text_body(socket net.Socket, subject, from, to, body string, debug bool) ? {
+	socket.send_string('From: $from\r\n')
+	socket.send_string('To: $to\r\n')
+	socket.send_string('Subject: $subject\r\n')
+	socket.send_string('\r\n\r\n')
+	socket.send_string(body)
+	socket.send_string('\r\n.\r\n')
+	bytes, blen := socket.recv(1024)
+	recv := recieved(bytes, blen)
+	println(recv)
+	if recv.len >= 3 {
+		status := recv[..3]
+		is_debug(debug, recv)
+		if status.int() != 250 {
+			return error('Replay (250) from server has not been recieved for EHLO.\nReplay recieved: $status')
+		}
+		println('V: Mail sent!')
+	} else {
+		return error('Recieved data from SMTP server is not returning supported values\nReturned values: $recv')
+	}
+}
+
+fn send_html_body(socket net.Socket, subject, from, to, body string, debug bool) ? {
+	socket.send_string('From: $from\r\n')
+	socket.send_string('To: $to\r\n')
+	socket.send_string('Subject: $subject\r\n')
+	socket.send_string('Content-Type: text/html; charset=ISO-8859-1')
+	socket.send_string('\r\n\r\n')
+	socket.send_string(body)
+	socket.send_string('\r\n.\r\n')
+	bytes, blen := socket.recv(1024)
+	recv := recieved(bytes, blen)
+	if recv.len >= 3 {
+		is_debug(debug, recv)
+		status := recv[..3]
+		if status.int() != 250 {
+			return error('Replay (250) from server has not been recieved for EHLO.\nReplay recieved: $status')
+		}
+		println('V: Mail sent!')
+	} else {
+		return error('Recieved data from SMTP server is not returning supported values\nReturned values: $recv')
+	}
+}
+
+fn auth(client net.Socket, username, password string, debug bool) ?bool {
+	cmd := Commands{}
+	mut sb := strings.new_builder(100)
+	sb.write_b(0)
+	sb.write(username)
+	sb.write_b(0)
+	sb.write(password)
+	mut x := sb.str()
+	x = base64.encode(x)
+	auth_cmd := cmd.auth_plain + x + '\r\n'
+	recv := send(client, auth_cmd)
+	if recv.len >= 3 {
+		is_debug(debug, recv)
+		status := recv[..3]
+		if status.int() != 235 {
+			return error('Replay (235) from server has not been recieved for AUTH.\nReplay recieved: $status')
+		}
+	} else {
+		return error('Recieved data from SMTP server is not returning supported values\nReturned values: $recv')
+	}
+	return true
+}
+
+fn recieved(bytes byteptr, blen int) string {
+	return tos(bytes, blen)
+}
+
+fn is_debug(debug bool, pr string) {
+	if debug == true {
+		println('\n...\n')
+		println(pr)
+	}
+}

vlib/net/smtp/smtp_test.v

@@ -0,0 +1,18 @@
+import smtp
+
+fn test_smtp() {
+
+	server := 'smtp.mailtrap.io'
+	port := 2525
+	username := '46d1daf3ff04f'
+	password := '1e8ba2dbf19f4f'
+	subject := 'Hello from V'
+	from := 'dev@vlang.io'
+	to := 'dev@vlang.io'
+	msg := '<h1>Hi,from V module, this message was sent by SMTP!</h1>'
+	body_type := 'html'
+	debug := true //use while debugging
+
+	smtp.send_mail(server, port, username, password, subject, from, to, msg, body_type,
+		debug)
+}