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Receiving Custom JSON Events via HTTP

Purpose

This application demonstrates how to configure WSO2 Integrator: SI to receive events to the SweetProductionStream via HTTP transport in JSON format using custom mapping and log the events in LowProductionAlertStream to the output console.

Executing the sample

  1. Start the Siddhi application by clicking on 'Run'.

  2. If the Siddhi application starts successfully, the following messages would be shown on the console.

    • Source Listener has created for url http://localhost:8006/productionStream
    • ReceiveHTTPInJsonFormatWithDefaultMapping.siddhi - Started Successfully!

Testing the sample

Publish events with http sample client

Navigate to <SI-Tooling-Home>/samples/sample-clients/http-client and run ant command as follows:

Run ant command in the terminal as follows:

ant -DcustomMapping=true

If you want to publish custom number of events, you need to run "ant" command as follows:

ant -DcustomMapping=true -DnoOfEventsToSend=5
Publish events with curl command

Publish few events in json format to the http endpoint as follows (The values for name and amount attributes can be changed as desired).

curl -X POST -d "{\"item\": {\"id\":\"Sugar\",\"amount\": 300.5}}"  http://localhost:8006/productionStream --header "Content-Type:application/json"
Publish events with Postman
  1. Launch the Postmane application.
  2. Make a POST request to http://localhost:8006/productionStream endpoint. Set the Content-Type to application/json and set the request body in json format as follows.
{
    "item": {
        "id": "sugar",
        "amount": 20.0
    }
}

Notes

If you edit this application while it's running, stop the application -> Save -> Start.

If the message Source Listener has created for url http://localhost:8006/productionStream does not appear,it could be due to the port 8006, defined in the Siddhi application is already being used by a different program. To resolve this issue, please do the following,

  • Stop this Siddhi application (Click 'Run' on menu bar -> 'Stop')
  • Change the port 8006 to an unused port, in this Siddhi application's source configuration.
  • Start the application and check whether the specified messages appear on the console.

Viewing the results

See the output. Following message would be shown on the console.

ReceiveHTTPInJsonFormatWithDefaultMapping : LowProducitonAlertStream : Event{timestamp=1511938781887, data=[sugar, 300.0], isExpired=false}

@App:name("ReceiveHTTPInJsonFormatWithCustomMapping")

@App:description('Receive events via HTTP transport in JSON format with custom mapping and view the output on the console')
@source(type = 'http',
        receiver.url='http://localhost:8006/productionStream',
        basic.auth.enabled='false',@map(type='json', @attributes( name = '$.item.id', amount = '$.item.amount')))
define stream SweetProductionStream (name string, amount double);

@sink(type='log')
define stream LowProductionAlertStream (name string, amount double);

-- passthrough data in the SweetProductionStream into LowProducitonAlertStream
@info(name='query1')
from SweetProductionStream
select *
insert into LowProductionAlertStream;