use crate::mqtt4::*;
use byteorder::WriteBytesExt;
pub trait MqttWrite: WriteBytesExt {
fn mqtt_write(&mut self, packet: &Packet) -> Result<(), Error> {
match packet {
Packet::Connect(connect) => {
self.write_u8(0b00010000)?;
self.write_remaining_length(connect.len())?;
self.write_mqtt_string("MQTT")?;
self.write_u8(0x04)?;
let mut connect_flags = 0;
if connect.clean_session {
connect_flags |= 0x02;
}
match &connect.last_will {
Some(w) if w.retain => connect_flags |= 0x04 | (w.qos as u8) << 3 | 0x20,
Some(w) => connect_flags |= 0x04 | (w.qos as u8) << 3,
None => (),
}
if let Some(_) = connect.password {
connect_flags |= 0x40;
}
if let Some(_) = connect.username {
connect_flags |= 0x80;
}
self.write_u8(connect_flags)?;
self.write_u16::<byteorder::BigEndian>(connect.keep_alive)?;
self.write_mqtt_string(connect.client_id.as_ref())?;
if let Some(ref last_will) = connect.last_will {
self.write_mqtt_string(last_will.topic.as_ref())?;
self.write_mqtt_string(last_will.message.as_ref())?;
}
if let Some(ref username) = connect.username {
self.write_mqtt_string(username)?;
}
if let Some(ref password) = connect.password {
self.write_mqtt_string(password)?;
}
Ok(())
}
Packet::Connack(connack) => {
let session_present = connack.session_present as u8;
let code = connack.code as u8;
let data = [0x20, 0x02, session_present, code];
self.write_all(&data)?;
Ok(())
}
Packet::Publish(publish) => {
self.write_u8(0b00110000 | publish.retain as u8 | ((publish.qos as u8) << 1) | ((publish.dup as u8) << 3))?;
let mut len = publish.topic_name.len() + 2 + publish.payload.len();
if publish.qos != QoS::AtMostOnce && None != publish.pkid {
len += 2;
}
self.write_remaining_length(len)?;
self.write_mqtt_string(publish.topic_name.as_str())?;
if publish.qos != QoS::AtMostOnce {
if let Some(pkid) = publish.pkid {
self.write_u16::<byteorder::BigEndian>(pkid.0)?;
}
}
self.write_all(&publish.payload.as_ref())?;
Ok(())
}
Packet::Puback(pkid) => {
self.write_all(&[0x40, 0x02])?;
self.write_u16::<byteorder::BigEndian>(pkid.0)?;
Ok(())
}
Packet::Pubrec(pkid) => {
self.write_all(&[0x50, 0x02])?;
self.write_u16::<byteorder::BigEndian>(pkid.0)?;
Ok(())
}
Packet::Pubrel(pkid) => {
self.write_all(&[0x62, 0x02])?;
self.write_u16::<byteorder::BigEndian>(pkid.0)?;
Ok(())
}
Packet::Pubcomp(pkid) => {
self.write_all(&[0x70, 0x02])?;
self.write_u16::<byteorder::BigEndian>(pkid.0)?;
Ok(())
}
Packet::Subscribe(subscribe) => {
self.write_all(&[0x82])?;
let len = 2 + subscribe.topics.iter().fold(0, |s, ref t| s + t.topic_path.len() + 3);
self.write_remaining_length(len)?;
self.write_u16::<byteorder::BigEndian>(subscribe.pkid.0)?;
for topic in subscribe.topics.as_ref() as &Vec<SubscribeTopic> {
self.write_mqtt_string(topic.topic_path.as_str())?;
self.write_u8(topic.qos as u8)?;
}
Ok(())
}
Packet::Suback(suback) => {
self.write_all(&[0x90])?;
self.write_remaining_length(suback.return_codes.len() + 2)?;
self.write_u16::<byteorder::BigEndian>(suback.pkid.0)?;
let payload: Vec<u8> = suback
.return_codes
.iter()
.map(|&code| match code {
SubscribeReturnCodes::Success(qos) => qos as u8,
SubscribeReturnCodes::Failure => 0x80,
})
.collect();
self.write_all(&payload)?;
Ok(())
}
Packet::Unsubscribe(unsubscribe) => {
self.write_all(&[0xA2])?;
let len = 2 + unsubscribe.topics.iter().fold(0, |s, ref topic| s + topic.len() + 2);
self.write_remaining_length(len)?;
self.write_u16::<byteorder::BigEndian>(unsubscribe.pkid.0)?;
for topic in unsubscribe.topics.as_ref() as &Vec<String> {
self.write_mqtt_string(topic.as_str())?;
}
Ok(())
}
Packet::Unsuback(pkid) => {
self.write_all(&[0xB0, 0x02])?;
self.write_u16::<byteorder::BigEndian>(pkid.0)?;
Ok(())
}
Packet::Pingreq => {
self.write_all(&[0xc0, 0])?;
Ok(())
}
Packet::Pingresp => {
self.write_all(&[0xd0, 0])?;
Ok(())
}
Packet::Disconnect => {
self.write_all(&[0xe0, 0])?;
Ok(())
}
}
}
fn write_mqtt_string(&mut self, string: &str) -> Result<(), Error> {
self.write_u16::<byteorder::BigEndian>(string.len() as u16)?;
self.write_all(string.as_bytes())?;
Ok(())
}
fn write_remaining_length(&mut self, len: usize) -> Result<(), Error> {
if len > 268_435_455 {
return Err(Error::PayloadTooLong);
}
let mut done = false;
let mut x = len;
while !done {
let mut byte = (x % 128) as u8;
x = x / 128;
if x > 0 {
byte = byte | 128;
}
self.write_u8(byte)?;
done = x <= 0;
}
Ok(())
}
}
impl<W: WriteBytesExt + ?Sized> MqttWrite for W {}
#[cfg(test)]
mod test {
use super::MqttWrite;
use crate::mqtt4::{Connack, Connect, Packet, Publish, Subscribe};
use crate::mqtt4::{ConnectReturnCode, LastWill, PacketIdentifier, Protocol, QoS, SubscribeTopic};
#[test]
fn write_packet_connect_mqtt_protocol_works() {
let connect = Packet::Connect(Connect {
protocol: Protocol::MQTT(4),
keep_alive: 10,
client_id: "test".to_owned(),
clean_session: true,
last_will: Some(LastWill {
topic: "/a".to_owned(),
message: "offline".to_owned(),
retain: false,
qos: QoS::AtLeastOnce,
}),
username: Some("rust".to_owned()),
password: Some("mq".to_owned()),
});
let mut stream = Vec::new();
stream.mqtt_write(&connect).unwrap();
assert_eq!(
stream.clone(),
vec![
0x10, 39, 0x00, 0x04, 'M' as u8, 'Q' as u8, 'T' as u8, 'T' as u8, 0x04,
0b11001110, 0x00, 0x0a, 0x00, 0x04, 't' as u8, 'e' as u8, 's' as u8, 't' as u8, 0x00, 0x02, '/' as u8, 'a' as u8, 0x00, 0x07, 'o' as u8, 'f' as u8, 'f' as u8, 'l' as u8, 'i' as u8, 'n' as u8, 'e' as u8, 0x00, 0x04, 'r' as u8, 'u' as u8, 's' as u8, 't' as u8, 0x00, 0x02, 'm' as u8, 'q' as u8 ]
);
}
#[test]
fn write_packet_connack_works() {
let connack = Packet::Connack(Connack {
session_present: true,
code: ConnectReturnCode::Accepted,
});
let mut stream = Vec::new();
stream.mqtt_write(&connack).unwrap();
assert_eq!(stream, vec![0b00100000, 0x02, 0x01, 0x00]);
}
#[test]
fn write_packet_publish_at_least_once_works() {
let publish = Packet::Publish(Publish {
dup: false,
qos: QoS::AtLeastOnce,
retain: false,
topic_name: "a/b".to_owned(),
pkid: Some(PacketIdentifier(10)),
payload: vec![0xF1, 0xF2, 0xF3, 0xF4],
});
let mut stream = Vec::new();
stream.mqtt_write(&publish).unwrap();
assert_eq!(
stream,
vec![0b00110010, 11, 0x00, 0x03, 'a' as u8, '/' as u8, 'b' as u8, 0x00, 0x0a, 0xF1, 0xF2, 0xF3, 0xF4]
);
}
#[test]
fn write_packet_publish_at_most_once_works() {
let publish = Packet::Publish(Publish {
dup: false,
qos: QoS::AtMostOnce,
retain: false,
topic_name: "a/b".to_owned(),
pkid: None,
payload: vec![0xE1, 0xE2, 0xE3, 0xE4],
});
let mut stream = Vec::new();
stream.mqtt_write(&publish).unwrap();
assert_eq!(
stream,
vec![0b00110000, 9, 0x00, 0x03, 'a' as u8, '/' as u8, 'b' as u8, 0xE1, 0xE2, 0xE3, 0xE4]
);
}
#[test]
fn write_packet_subscribe_works() {
let subscribe = Packet::Subscribe(Subscribe {
pkid: PacketIdentifier(260),
topics: vec![
SubscribeTopic {
topic_path: "a/+".to_owned(),
qos: QoS::AtMostOnce,
},
SubscribeTopic {
topic_path: "#".to_owned(),
qos: QoS::AtLeastOnce,
},
SubscribeTopic {
topic_path: "a/b/c".to_owned(),
qos: QoS::ExactlyOnce,
},
],
});
let mut stream = Vec::new();
stream.mqtt_write(&subscribe).unwrap();
assert_eq!(
stream,
vec![
0b10000010, 20, 0x01, 0x04, 0x00, 0x03, 'a' as u8, '/' as u8, '+' as u8, 0x00, 0x00, 0x01, '#' as u8, 0x01, 0x00, 0x05, 'a' as u8, '/' as u8, 'b' as u8, '/' as u8, 'c' as u8, 0x02 ]
);
}
}