net-mqtt
An MQTT Protocol Implementation.
https://github.com/dustin/mqtt-hs#readme
Version on this page: | 0.8.2.5 |
LTS Haskell 22.40: | 0.8.6.1 |
Stackage Nightly 2023-12-26: | 0.8.6.0 |
Latest on Hackage: | 0.8.6.1 |
net-mqtt-0.8.2.5@sha256:de363c4dc55ca75710fa05b9830cdabecd183188db538e18b56afcaca771c6bf,4107
Module documentation for 0.8.2.5
- Network
mqtt
An MQTT protocol implementation for Haskell.
Client Examples
Publish
import Network.MQTT.Client
import Network.URI (parseURI)
main :: IO ()
main = do
let (Just uri) = parseURI "mqtt://test.mosquitto.org"
mc <- connectURI mqttConfig uri
publish mc "tmp/topic" "hello!" False
Subscribe
import Network.MQTT.Client
import Network.URI (parseURI)
main :: IO ()
main = do
let (Just uri) = parseURI "mqtt://test.mosquitto.org"
mc <- connectURI mqttConfig{_msgCB=SimpleCallback msgReceived} uri
print =<< subscribe mc [("tmp/topic1", subOptions), ("tmp/topic2", subOptions)] []
waitForClient mc -- wait for the the client to disconnect
where
msgReceived _ t m p = print (t,m,p)
Changes
Changelog for net-mqtt
0.8.2.4
Minor build changes and code cleanup. Includes LTS update.
0.8.2.3
Quick release for updating LTS and deps. Wasn’t committed and pushed because I got lazy.
0.8.2.2
Fix for pub flow messages with 0 length properties that are explicitly encoded.
Thanks to Marc Jakobi for pointing this out.
0.8.2.1
A fix allowing the filter to wildcards to match their parent as per spec.
This is not very intuitive and kind of seems like a bad idea, but the spec says this is how it works.
Thanks to Noah Halford.
0.8.2.0
Added OrderedCallback
and OrderedLowLevelCallback
to guarantee
processing the messages in order.
SimpleCallback
and LowLevelCallback
both run callbacks in isolated
threads such that when a message takes longer to process than another,
a second message might finish before the first. Most of the time,
this probably doesn’t matter this model is simpler and keeps latency
lower. Now applications can decide what’s appropriate for them.
0.8.1.0
Added toFilter
to convert Topic
s to Filter
s.
(Thanks Matt Friede)
0.8.0.2
Exported arbitraryFilter
for more control over filter creation.
0.8.0.1
Added an Arbitrary
instance for Filter
.
0.8.0.0
The Topic
and Filter
types are now newtype
wrappers around Text
instead of being aliases for text. This is a breaking change, but
makes a lot of bugs harder to express. There’s a split
function
available that will split a Topic
or Filter
into components, and
both types are Semigroup
s joining on /
.
Because these are newtype
s, we the Arbitrary
instances don’t need
special wrappers, so ATopic
is gone in favor of just Topic
’s
Arbitrary
instance.
0.7.1.0
More Arbitrary topic helpers.
Commandline tool enhancements.
Bump version bounds.
0.7.0.1
Fixed an error where there’d be an ugly crash in a situation where
connections were failing regularly and we detected the failure before
a connection thread spun up. I was using undefined
for the default
thread value because it was intended to be immediately set, but did
find a way to get there in a failure storm. It’s a Maybe
now.
fail on unexpected packets. I had a print
in there from very early
on. Proper sequences are covered, but if a broker sends the client an
unexpected packet, it’d be good to not just ignore it.
When publishing, “no matching subscribers” should not be considered a failure. It’s also not bubbled up to the caller, but it is returned as an error from the broker to basically say the publish was successful, but nobody cares about the thing you published.
mqtt-watch will automatically reestablish sessions by default without reissuing subscriptions (including auto-generated client IDs).
0.7.0.0
ConnACKFlags
now has a SessionReuse
type which makes it very clear
whether the session is resuming. I was affected by the boolean
blindness of the previous variant myself several times.
Connection _properties
is now called _connProperties
. I developed
a separate net-mqtt-lens
package that provides a lens into all
properties of all types that have properties, but a bit more
consistency here is good.
QoS
now has an Ord
instance.
A new PktID
type alias makes it clear which Word16
values were
meant to represent a packet ID.
There are fewer threads in publish handling in both directions. This mostly just simplified things, but it also helped prevent a few races when a lot of values arrived at the same time.
0.6.2.3
Remove a use of fail
that prevents us from building under ghc 8.8.
0.6.2.2
Support query parameters in ws and wss URLs.
0.6.2.1
Added function to get original connection ACK response packet.
- connACK (in IO) and connACKSTM
0.6.2.0
Added low-level support for correlated responses.
I’m not completely sure how generally useful this interface is, but I’ve been using it in a client that’s implementing an RPC type interface across MQTT for a bit now.
0.6.1.1
Add connection checks to publish phases.
Having a broker/connection die in the middle of a publish in QoS > 0 could result in a thread waiting indefinitely for the response that would not ever arrive.
0.6.1.0
Users can now specify TLSSettings for mqtts:// and wss:// connections.
Small bit of refactoring of main threads used by the client. It’s a bit easier to reason about their lifecycle now.
All (at least most) of the threads in use by the client are named so when you’re looking at an eventlog, you can see what’s coming and going.
0.6.0.2
Export MQTTException (thrown from various internal bits).
Added isConnectedSTM for verifying connection state inside of STM transactions (e.g., verifying you’re connected while also waiting for a value in a TChan).
Also, mqtt-watch reconnects on error now.
0.6.0.1
Relaxed QuickCheck constraint slightly.
Added connection timeout.
0.6.0.0
Many changes went into this release.
New Features
- WebSocket support (ws:// and wss://)
- Added the
mqtt-watch
CLI tool (which I use a lot) - Lots of work on correctness WRT connection and callback failures.
- Low-Level callbacks (providing all the details of the published message)
- Added
runMQTTConduit
to allow running the client over any Conduit provider.
Incompatibilities
As part of adding features and improving correctness, I’ve made a few API changes.
waitForClient
now throws an exception on failure. This greatly simplified usage and has made a variety of my applications more reliable when networks and computers fail.- Callbacks are now
MessageCallback
. This primarily allowed me to separateSimpleCallback
(the thing most apps want) andLowLevelCallback
(a thing I needed when building an MQTT bridge). - Removed
runClient
andrunClientTLS
from the API. They don’t provide any value overconnectURI
orrunMQTTConduit
. - All callbacks are now asynchronous. Before, QoS2 would be by necessity, but a bad callback could cause problems with the machinery, so they’re all independent now. This may not be noticeable in most applications, but it’s something to consider.
0.5.1.0
The QuickCheck Arbitrary instances are exported in a module now, allowing programs to generate useful tests other implementations of mqtt. I’ve been using this package to test a C implementation.
Also, don’t allow 3.1.1 to generate a password without a username. That’s kind of a weird limitation in the older protocol I’m not sure anyone’s run into, but the spec says not to encode things on the wire that way, so it’s useful for interop testing.
0.5.0.2
With a few attempts to misuse the library, I found some places where error messages weren’t useful enough. There were still two cases where failures turned into indefinite STM errors instead of more informative errors. 1) when the broker declined your connection and 2) when the broker refused your connection. These are errors at differnet layers, so were addressed differently, but should be informative in both cases now.
Unsubscribe was apparently broken in MQTT 5 as well. I’d never tried to use it, and just happened to notice it wasn’t quite right.
0.5.0.1
Now with no known issues.
0.5.0.0 was released without consulting the github issues page. There were two open bugs – one had already been fixed in the development of 0.5, but another was still present.
0.5.0.0 named the default subscription options defaultSubOptions
,
but that’s inconsistent with other defaults, so it was renamed to
subOptions
. This is technically an API incompatibility being
introduced and I wouldn’t normally do that, but the API’s been out for
a few hours, so I’m preeptively asking for forgiveness.
0.5.0.0
Major release for MQTT version 5.
The API is mostly the same, but a list of Property values is passed in and returned from a few different fields.
Subscribe responses are now more detailed in the error case, and also
return a [Property]
.
Connections default to Protocol311
(3.1.1), and all behavior should
be backwards compatible in these cases. i.e., you can write code as
if it were destined for a v5 broker, but properties won’t be sent and
responses will be inferred. If you specify your _protocol
as
Protocol50
in your MQTTConfig
, the new features should all work.
Various bugs were fixed along the path of making v5 compatibility, but I’m pretty sure there’s one left somewhere.
0.2.4.2
Don’t set a message ID of 0.
This had been working fine for a while, but starting in mosquitto 1.6, the server would just hang up on a subscribe request with a message ID of zero.
0.2.4.1
Link QoS2 completion thread on subscriber.
An exception from a subscriber callback could be silently dropped without completing the handshake which would then cause the MQTT broker to just stop sending messages to the subscriber. Unfortunately, the broker (at least mosquitto) still responds to pings and doesn’t give any useful notification that it’s no longer sending messages.
0.2.4.0
Introduced Filter
type alias to distinguish from Topic
.
Reintroduced timeout management at the protocol layer, dropping a connection when a pong response hasn’t come in in a while (~3x longer than the current 30s ping rate). This was mostly after noticing mosquitto do really weird things where it seemed to just forget about all my active connections (other clients figured that out and dropped and reconnected).
0.2.3.1
Fixed up github links.
0.2.3.0
Added Network.MQTT.Topic with match
to test Topic
s against wildcards.
0.2.2.0
Added connectURI to make it easier to connect to mqtt or mqtts via URI.
0.2.1.0
No externally visible changes, but a few bug fixes I found when writing an application that published in QoS < 2. QoS 0 would likely not transmit (which is probably fine according to the spec, but not very desirable) and QoS1 didn’t check its ACKs, so it would continue to retry after the server ACKd the message.
0.2.0.0
API Change
Subscriber callbacks now include the MQTT client as the first argument. This breaks a circular dependency that prevented callbacks from being able to publish messages easily.
Other
Updated to stackage LTS 13.2