live

Live updating templates connected to MQTT topics.

Note

The live tag is provided by mod_mqtt, which must be enabled.

This tag renders templates that are automatically re-rendered after a publication to an MQTT topic.

Example

An example of a template showing the newest content of a resource:

{% live template="_detail.tpl" topic=id id=id %}

This renders the template _detail.tpl. If the resource with id id is updated then the template will be replaced with a freshly rendered template.

The tag can subscribe to multiple topics at once.

Add the argument catinclude to do a catinclude instead of a normal include. For a catinclude the argument id must be present:

{% live template="_detail.tpl" topic=id catinclude id=id %}

Live topics

Any MQTT topic can be used. The topics are interpreted as local to the page. There are three special topics:

• Use any integer to map to the resource’s update topic. For example if id is 1234 then the topic will be bridge/origin/model/rsc/event/1234

• Use the tuple {object id=...} to listen to changes of outgoing connections from a page. An example of a mapped topic is bridge/origin/model/edge/event/1234/o/+`. Use the tuple {object id=... predicate=...} to listen to changes of a specific predicate of a page. An example of a mapped topic is bridge/origin/model/edge/event/1234/o/author

• Use the tuple {subject id=... } to listen to changes of incoming connections to a page. An example of a mapped topic is bridge/origin/model/edge/event/1234/s/author

Note that the topics refer to client side topics, that is why the bridge is used to subscribe to server side model events.

It is possible to subscribe to client topics like "my/local/topic" and have the actions triggered by publish to cotonic.broker.publish("my/local/topic", {}); (with any payload).

Live actions

It is possible to wire actions or postbacks to a MQTT topic.

Use the wire tag with argument type={mqtt topic=... topic=...} to connect to one or more MQTT topics:

{% wire type={mqtt topic="bridge/origin/public/hello"} action={growl text="hello"} %}

And in Erlang this will trigger the above growl:

z_mqtt:publish(<<"public/hello">>, <<>>, z:c(mysite)).