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Publishing JSON Events via TCP

Purpose

This application demonstrates how to configure WSO2 Integrator: SI to send sweet production events via TCP transport in JSON format, and view the output in your TCP server's console.

Prerequisites

Try it out

  1. Start your TCP server, listening on port 9892 and accepting events for context LowProductionAlertStream.

  2. Start the Siddhi application by clicking Run. The following messages appear in the console:

    • PublishTcpInJsonFormat.siddhi - Started Successfully!
    • 'tcp' sink at 'LowProductionAlertStream' stream successfully connected to 'localhost:9892'.

    Connection error?

    If you see 'LowProductionAlertStream' stream could not connect to 'localhost:9892', your TCP server may not be running, or the port may be in use by another program. Verify your TCP server is listening on 9892, or change the port in both the sink configuration and your server.

  3. Send events using the Event Simulator. For instructions, see Testing Siddhi Applications. Use the following values:

    Field Value
    Siddhi App Name PublishTcpInJsonFormat
    Stream Name SweetProductionStream
    name toffee
    amount 45.24

    Send a few more events with different values.

  4. Your TCP server receives the JSON-encoded events. Sample output (formatting depends on your server implementation):

    Event{timestamp=1512446413468, data=[toffee, 45.25], isExpired=false}
Event{timestamp=1512446425113, data=[coffee, 9.78], isExpired=false}
Event{timestamp=1512446442300, data=[chocolate, 78.23], isExpired=false}

Siddhi application

@App:name("PublishTcpInJsonFormat")
@App:description('Send events via TCP transport using json format')

define stream SweetProductionStream (name string, amount double);

@sink(type='tcp', url='tcp://localhost:9892/LowProductionAlertStream',
@map(type='json'))
define stream LowProductionAlertStream (name string, amount double);

from SweetProductionStream
select *
insert into LowProductionAlertStream;
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Last update: May 14, 2026