Changes Between 1.0.0-beta8 and 1.0.0-beta9

Subscription API Change

Previously clojurewerkz.machine-head.client/subscribe accepted a list of topics and optionally a list of QoS levels:

(mh/subscribe c ["mh/topics/#" "mh/alt.topics/+"]
                  (fn [^String topic meta ^bytes payload])
                  {:qos [0 1]})

This turns out to be a fairly confusing API.

We've changed it to accept a map of topics to QoS levels. While a bit more verbose, this API make it very clear what topic will use what QoS:

(mh/subscribe c {"mh/topics/#" 0 "mh/alt.topics/+" 1}
                  (fn [^String topic meta ^bytes payload] ))

Changes Between 1.0.0-beta7 and 1.0.0-beta8

Clojure 1.6 By Default

The project now depends on org.clojure/clojure version 1.6.0. It is still compatible with Clojure 1.4 and if your project.clj depends on a different version, it will be used, but 1.6 is the default now.

We encourage all users to upgrade to 1.6, it is a drop-in replacement for the majority of projects out there.

Changes Between 1.0.0-beta6 and 1.0.0-beta7

Retain Default Change

When publishing, retain now defaults to false, which is a much more sensible default.

Contributed by Martin Trojer.

Changes Between 1.0.0-beta5 and 1.0.0-beta6

:clean-session Accepts false

It is now possible to set :clean-session to `false.

Contributed by Martin Trojer.

Changes Between 1.0.0-beta4 and 1.0.0-beta5

Last Will and Testament

Machine Head now supports providing client last will and testament:

(require '[clojurewerkz.machine-head.client :as mh])

(let [will {:topic "lw-topic" :payload (.getBytes "last will") :qos 0 :retain false}]
  (mh/connect "" (mh/generate-id) {:will will}))

Contributed by Paul Bellamy.

Changes Between 1.0.0-beta3 and 1.0.0-beta4

Client ID Limit

MQTT spec dictates that client ID's should be limited to 23 bytes. Eclipse Paho client generator can produce ID's longer than that.

Machine Head now will limit ID length to the last 23 bytes.

Contributed by Yodit Stanton.

Changes Between 1.0.0-beta2 and 1.0.0-beta3

Clean Session Support

clojurewerkz.machine-head.client/connect now supports one more option: :clean-session. When set to true, the option means that the client and MQTT broker should discard state that might have been kept from earlier connections.

Changes Between 1.0.0-beta1 and 1.0.0-beta2

client/subscribe-with-qos is Removed

clojurewerkz.machine-head.client/subscribe-with-qos is removed. Instead, clojurewerkz.machine-head.client/subscribe now takes a new option, :qos.

Contributed by Martin Trojer.

Disconnect and Close

More Flexible Publish

clojurewerkz.machine-head.client/disconnect-and-close is a new function that's identical to clojurewerkz.machine-head.client/disconnect but also releases all resources used by the client (e.g. file descriptors used by durable write-ahead log).

More Flexible Publish

clojurewerkz.machine-head.client/publish now also accepts MqttMessage instances that makes it easy to republish pending messages returned by clojurewerkz.machine-head.client/pending-messages.

Pending Messages

clojurewerkz.machine-head.client/pending-messages is a new function that is similar to clojurewerkz.machine-head.client/pending-delivery-tokens but returns messages instead of delivery tokens (identifiers). It returns a lazy sequence.

The sequence can only be non-empty if client terminated before finishing delivering all previously published messages.

Pending Delivery Tokens

clojurewerkz.machine-head.client/pending-delivery-tokens is a new function that takes a client and returns a collection of pending delivery tokens. The collection can only be non-empty if client terminated before finishing delivering all previously published messages.

Machine Head 1.0.0-beta1 (initial release)

Core Functionality

Machine Head beta1 supports connecting to MQTT brokers (tested against Mosquitto and RabbitMQ MQTT plugin), topic subscriptions and publishing.

The API is a subject to change at any time.