SSE

<SSE/> : DataSource

The SSE opens a connection between the application and an API that receives server side events notifications asynchronously.

Restrictions:

• A SSE is intended for one way communication, if you need bi-directional consider a WebSocket or a HTTP method for sending from client to server such as GET / POST datasources.

Parent:

Datasources

Attributes

Name	Type	Default	Description	Req
id	string	null	The id of the widget used for databinding.	✔
url	string	null	The url that opens the server side event connection.	✔
events	string	"message"	A comma seperated string specifying the valid event types to trap.
autoexecute	bool	true	If the widget will fire when the template is first opened or on url change
tti	int(s,m,h)	5s	The time the Datasources status will stay as anything but idle.
onsuccess	string/Event	null	The string of events the broker will execute upon a successful query.
onfail	string/Event	null	The string of events the broker will execute upon a failed query.

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

Name	Type	Description
start()		Establishes a connection to the server. Invoked in any EVENT string using <id>.start()
connect()		Establishes a connection to the server. Invoked in any EVENT string using <id>.connect()
stop()		Closes the connection. Invoked in any EVENT string using <id>.stop()
disconnect()		Closes the connection. Invoked in any EVENT string using <id>.disconnect()

Properties

Name	Type	Default	Description	Req
rowcount	int	0	The number of records in the data bindable
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.
httpstatus	string	null	Returns the generic message associated with the http status code.

Headers

The default HTTP headers are as follows:

• age = '0';
• content-encoding= 'utf8';
• content-type = "application/xml";
• authorization = JWT TOKEN

If the <HEADERS> element is specified, the defaults headers are omitted and replaced with those specified.

Example #1

This example demonstrates how to omit all headers.

<HEADERS/>

Examples

(fig. a)

<SSE id="sse1" autoexecute="true" url="https://sse.dev/test" messagetypes="put,post,message"/>
<TEXT label="=todate({sse1.data.now})"/>

See it in Action

Other Widgets You May Find Useful

• Datasources
• GET
• POST
• WEBSOCKET