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Publishing Custom XML Events via HTTP

Purpose

This application demonstrates how to configure WSO2 Streaming Integrator to send sweet production events via HTTP transport in XML format using custom mapping. Map the input events($.item.id) to stream events(name) and log the events in the LowProducitonAlertStream stream on the output console.

Before executing the sample:

Save the sample Siddhi application. Is there is no syntax error, the following message appears in the console.
Siddhi App PublishHttpInXmlFormatWithCustomMapping successfully deployed.

Executing the sample

  1. Start the Siddhi application by clicking Run => Run.

  2. If the Siddhi application starts successfully, the following message appears in the console.

    PublishHttpInXmlFormatWithCustomMapping.siddhi - Started Successfully!

Note

  • If you edit this application while it's running, save the application and then click Run => Run.

  • If the PublishHttpInXmlFormatWithCustomMapping.siddhi - Started Successfully! message does not appear, it could be due to the port 8080 which is defined in the Siddhi application already being used by a different program. To resolve this issue, do the following:

    • Stop this Siddhi application (click 'Run' on the menu bar -> 'Stop')..
    • Change the port 8080 to an unused port in this Siddhi application's source configuration..
    • Start the application and check whether the specified messages appear on the console.

Testing the sample

Open a terminal and navigate to <SI-Tooling-Home>/samples/sample-clients/http-server. Then run the ant command without any arguments. Send events using one or more of the following methods:

Send events with the HTTP server through the event simulator
  1. Open event simulator by clicking on the second icon or press Ctrl+Shift+I.
  2. In the Single Simulation tab of the panel, select values as follows:
    • Siddhi App Name: PublishHttpInXmlFormatWithCustomMapping
    • Stream Name: SweetProductionStream
  3. In the name field and amount fields, enter toffee and 50.0 respectively. Then click Send to send the event.
  4. Send more events.
Send events using the CURL command

Send event to the HTTP endpoint defined via the publish.url in the Sink configuration by issuing the following CURL command

curl -X POST -d '{"streamName": "SweetProductionStream", "siddhiAppName": "PublishHttpInXmlFormatWithCustomMapping","data": ['toffee', 67.43]}' http://localhost:9390/simulation/single -H 'content-type: text/plain'

If there is no error, the following message appears in the terminal:

{"status":"OK","message":"Single Event simulation started successfully"}

Viewing the results

  • If you send events through the event simulator, the following output is logged.
[java] [org.wso2.si.http.server.HttpServerListener]: `Event Name Arrived: <events><event><name>toffee</name><amount>50.0</amount></event></events>`
[java] [org.wso2.si.http.server.HttpServerMain]: `Received Event Names:<events><event><name>toffee</name><amount>50.0</amount></event></events> ,`
[java] [org.wso2.si.http.server.HttpServerMain]: `Received Event Headers key set:[Http_method, Transfer-encoding, Content-type]`
[java] [org.wso2.si.http.server.HttpServerMain]: `Received Event Headers value set:[[POST], [chunked], [application/xml]]`
  • If you send events through event CURL commands, the following output is logged:
[java] [org.wso2.si.http.server.HttpServerListener]: `Event Name Arrived: <events><event><name>toffee</name><amount>67.43</amount></event></events>`
[java] [org.wso2.si.http.server.HttpServerMain]: `Received Event Names:<events><event><name>toffee</name><amount>67.43</amount></event></events> ,`
[java] [org.wso2.si.http.server.HttpServerMain]: `Received Event Headers key set:[Http_method, Transfer-encoding, Content-type]`
[java] [org.wso2.si.http.server.HttpServerMain]: `Received Event Headers value set:[[POST], [chunked], [application/xml]]`

Note

Stop this Siddhi application once you are done with the execution.

@App:name("PublishHttpInXmlFormatWithCustomMapping")
@App:description('Send events via HTTP transport using xml formatwith custom mapping')

define stream SweetProductionStream (name string, amount double);

@sink(type='http', publisher.url='http://localhost:8080/abc',
@map(type='xml', @payload( "<StockData><Symbol>{{ name }}</Symbol><Price>{{ amount }}</Price></StockData>")))
define stream LowProductionAlertStream (name string, amount double);

from SweetProductionStream
select *
insert into LowProductionAlertStream;