MQTT - AppDaddy-Software-Solutions-Inc/framework-markup-language GitHub Wiki

<MQTT/> : DataSource

The MQTT Datasource is a direct link to Active MQ. This can be used to subscribe to, access and send messages to specific topics. The Datasource uses all of its base widget properties and transforms such as FILTER. For more information on Active MQ and MQTT, visit https://activemq.apache.org/.

Table of Contents

Usage

The [MQTT] Datasource is used to listen to, read, and write to ActiveMQ Streams. It uses the same Properties as Datasources. System wide messages can be broadcast across multiple templates by placing the MQTT broker at the root template ie. MAIN.xml. Elements in the posting body are converted to a table and can be FILTERED.

Ideals:

  • To message users, admins, and interface with active mq.
  • To alert users using system wide messages.

Restrictions:

  • The MQTT widget uses only non-durable subscriptions.
  • A user must be connected to the network to be subscribed.
  • Body and Topic are the only automatically added bindables.

MQTT Attributes

Name Type Default Description Req
id string null The id of the widget used for databinding. ✔
subscriptions string, string, ... null A comma seperated list of subscription names to connect to ✔
username string null Username credentials to use for connection
password string null Password credentials to use for connection
autoexecute bool true If the widget will fire when the template is first opened or on url change
status string idle The status of the broker, returns error, success or idle.
statusmessage string null Returns a status message (usually from the response on an exception ).
statuscode string null Returns the http status code.

Attributes (Data Specific)

Name Type Default Description Req
data List of item where item is a Map<String, String> or another List of item If the response is encoded as valid json or xml it is deserialized and addressable using DOTNOTATION
queueType string replace replace, lifo, fifo, append, prepend. Defines the data aggregation strategy for data returned from initial and subsequent calls. replace (default) replaces all data after each subsequent call. lifo (last in first out), fifo (first in first out), append and prepend are all used in conjunction with the maxrecords attribute
maxrecords int 10000 The maximum size data can grow to. This works in concert with type
root string The root tag that defines the repeatable items in data. This can be a nested field. If not specified, the list is segmented by the first repeatable element found in the data set
ttl int(s,m,h) 0s Time to Live caches data in the local persistent HIVE database for the period specified. This saves requerying data that changes infrequently
rowcount int 0 The number of records in data

Methods (Data Specific)

Name Type Description
clear() Clears data. Invoked in any EVENT string using <id>.clear()
add(jsonOrXml, index) string, int Deserializes the jsonOrXml string and adds it to the end of data or at position index if specified. Invoked in any EVENT string using <id>.add(jsonOrXml, index)
remove(index) int Removes the last item from data or from position index if specified. Invoked in any EVENT string using <id>.remove(index)
reverse() Reverses data. Invoked in any EVENT string using <id>.reverse()

Events :: datasource

Name Type Default Description Req
onmessage string null The string of events the broker will execute on each and every message received
onsuccess string null The string of events the broker will execute when the connection is closed.
onconnected string null The string of events the broker will execute when the connection is successfully opened
ondisconnected string null The string of events the broker will execute when the connection is successfully closed
onerror string null The string of events the broker will execute when a connection error is detected
onsubscribed string null The string of events the broker will execute when a subscription is successfully opened
onunsubscribed string null The string of events the broker will execute when a subscription is closed
onpublished string null The string of events the broker will execute when a message has been successfully written to the subscription

Examples

<MQTT id="DB1" method="read" url=":61614/chat" type="append"/> <!--This is a subscription listening to the chat topic-->
<MQTT id="PB1" method="write" body="{newmsg}" url=":61614/chat">
</MQTT> <!--This is a subscription to post to the chat topic-->

These are two MQTT widgets using read and write, showing how to call the widget.

<MQTT id="DB1" url="mqtt://appdaddy.co:61614/chat" type="append"/> <!--This is a subscription listening to the chat topic-->
<MQTT id="PB1" url="mqtt://appdaddy.co:61614/chat">
<BODY>
<MQ>
	<from>
		{SYSTEM.username}
	</from>
	<message>
		{newmsg}
	</message>
</MQ>
</BODY>
</MQTT> <!--This is a subscription to post to the chat topic-->
<COLUMN>
<BOX width="100%" height="50%">
<LIST data="DB1" height="80%">
	<ITEM>
			<COL>
			<PADDING all="10">
			<TEXT label="{topic}" color="black" size="11"/>
			<TEXT value="{message}" color="black" size="11"/>
			</PADDING>
			</COL>
	</ITEM>
</LIST>
</BOX>
		<BOX width="100%">
		<INPUT hint="new message" id="newmsg" lines="6" width="100%"/>
		<BUTTON label="Send" onclick="PB1.start();newmsg.set('')" color="grey"/>
		</BOX>

	</COLUMN>	
</TEMPLATE>

This is an example of a live chat style template, where a user can send and receive messages to a topic.


### Other Widgets You May Find Useful
- [DataSource](./DataSource)

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