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In this section, let's see how to add the required configurations to receive events via HTTP in JSON format.

1. Let's open the SweetTotalsAppSweetTotalApp Siddhi application that you created in the previous tutorial. It currently looks as follows.

   Code Block
   language sql
   @App:name('SweetTotalApp') define stream SweetProductionStream (name string, amount long); @sink(type='log', prefix='Sweet Totals:') define stream SweetTotalStream(name string, totalProduction long); @info(name='SweetTotalQuery') from SweetProductionStream select name, sum(amount) as totalProduction group by name insert into SweetTotalStream;

2. To receive the events generated by the Sweet Bots via HTTP calls, you need an event source of the http type. Let's add it as shown below.

   Code Block
   language sql
   @source(type='http')

3. The HTTP events need to be received at a specific endpoint. Let's add the URL of this endpoint to the HTTP source configuration as follows:

   Panel
   @source(type='http', receiver.url='http://localhost:5005/SweetProductionEP')

4. The incoming messages generated by Sweet Bots are in the JSON format. You require a mapping configuration to transform them into a format that can be processed by WSO2 SP. Therefore, let's add an annotation for JSON mapping to the HTTP source as shown below.

   Info
   For the complete list of mapping types supported for WSO2 SP, see Collecting Events - Event Format.

   Panel
   @source(type='http', receiver.url='http://localhost:5005/SweetProductionEP', @map(type = 'json'))

   Now the SweetTotalsApp SweetTotalApp Siddhi application looks as follows.

   Code Block
   language sql
   @App:name('SweetTotalApp') @source(type='http', receiver.url='http://localhost:5005/SweetProductionEP', @map(type = 'json')) define stream SweetProductionStream (name string, amount long); @sink(type='log', prefix='Sweet Totals:') define stream SweetTotalStream(name string, totalProduction long); @info(name='SweetTotalQuery') from SweetProductionStream select name, sum(amount) as totalProduction group by name insert into SweetTotalStream;

5. Save the SweetTotalsAppSweetTotalApp Siddhi application. Then click the following icon to start it so that it can process the events you send.
    

6. To see whether the Siddhi application functions as expected, let's send two events with the following information.

   The input events generated by the Sweet Bots are in the JSON format. Therefore, the format is similar to the sample shown below.

   Code Block
   language js
   { "event": { "name": "Jaffa Cake", "amount": 10 } }

   In order to send the two input events to WSO2 SP in the format shown above, issue the following two cURL commands.

   Code Block
   curl -X POST \ http://localhost:5005/SweetProductionEP \ -H 'content-type: application/json' \ -d '{ "event": { "name": "Jaffa Cake", "amount": 10 } }'

   Code Block
   curl -X POST \ http://localhost:5005/SweetProductionEP \ -H 'content-type: application/json' \ -d '{ "event": { "name": "Jaffa Cake", "amount": 15 } }'

   The two events sent contains the following information.

   Input Event No	Name	Amount
   1	Jaffa Cake	10
   2	Jaffa Cake	15

   As a result, two output events are expected to be generated with the following information.

   Output Event No	Name	Amount
   1	Jaffa Cake	10
   2	Jaffa Cake	25

   This generates the following output log in the CLI.

   

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1. To allow the Siddhi application to identify the elements that need to be extracted from the JSON message, add an @attributes annotation to the mapping configuration as follows.
   

   Panel
   @map(type = 'json', @attributes(...))

   
   

   
   

2. The JSON mapper supports JsonPath. Therefore, the values for the attributes annotation can be JsonPath expressions. The JsonPath expressions for the name of the sweet and its total production are as follows.

   Stream Attribute Name	JSON Event Attribute Name	JsonPath Expression
   name	sweet	$.sweet
   amount	count	$.batch.count

   Based on the above JsonPath expressions you identified, you can update the @attributes annotation as follows.

   Code Block
   language js
   @attributes(name = '$.sweet', amount = '$.batch.count')

   Once thie above substeps are completed, the mapping configuration looks as follows.

   Code Block
   language js
   @map(type = 'json', @attributes(name = '$.sweet', amount = '$.batch.count')

   The complete Siddhi application looks as follows.

   Code Block
   language sql
   @App:name('SweetTotalApp') @source(type='http', receiver.url='http://localhost:5005/SweetProductionEP', @map(type = 'json', @attributes(name = '$.sweet', amount = '$.batch.count'))) define stream SweetProductionStream (name string, amount long); @sink(type='log', prefix='Sweet Totals:') define stream SweetTotalStream(name string, totalProduction long); @info(name='SweetTotalQuery') from SweetProductionStream select name, sum(amount) as totalProduction group by name insert into SweetTotalStream;

3. Let's save the changes you made to SweetTotalsAppSweetTotalApp Siddhi application. Then click the following icon to start it so that it can process the events you send.
    

4. Now you can issue the following cURL commands to send the two incoming events as sent by the Sweet Bots.

   Code Block
   curl -X POST \ http://localhost:5005/SweetProductionEP \ -H 'content-type: application/json' \ -d '{ "sweet": "Jaffa Cake", "batch": { "batch id": "batch1", "count": 10 } }'

   Code Block
   curl -X POST \ http://localhost:5005/SweetProductionEP \ -H 'content-type: application/json' \ -d '{ "sweet": "Jaffa Cake", "batch": { "batch id": "batch1", "count": 15 } }'

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