http-service-response (Sink)

The http-service-response sink send responses of the requests consumed by its corresponding http-service source, by mapping the response messages to formats such as text, XML and JSON.

Syntax

CREATE SINK <NAME> WITH (type="http-service-response", map.type="<STRING>", source.id="<STRING>", message.id="<STRING>", headers="<STRING>")

Query Parameters

Name	Description	Default Value	Possible Data Types	Optional	Dynamic
source.id	Identifier to correlate the http-service-response sink to its corresponding http-service source which consumed the request.		STRING	No	No
message.id	Identifier to correlate the response with the request received by http-service source.		STRING	No	Yes
headers	HTTP request headers in format "'<key>:<value>','<key>:<value>'". When the Content-Type header is not provided the system decides the Content-Type based on the provided sink mapper as following: - map.type='xml': application/xml - map.type='json': application/json - map.type='text': plain/text - map.type='keyvalue': application/x-www-form-urlencoded - For all other cases system defaults to plain/text Also the Content-Length header need not to be provided, as the system automatically defines it by calculating the size of the payload.	Content-Type and Content-Length headers	STRING	Yes	No

Example 1

CREATE SOURCE AddStream WITH (type='http-service', receiver.url='http://localhost:5005/add', source.id='adder', map.type='json, map.attributes="messageId='trp:messageId', value1='$.event.value1', value2='$.event.value2'") (messageId string, value1 long, value2 long);

CREATE SINK ResultStream WITH (type='http-service-response', source.id='adder', message.id='{{messageId}}', map.type='json') (messageId string, results long);

@info(name = 'query1')
from AddStream
select messageId, value1 + value2 as results
insert into ResultStream;

The http-service source on stream AddStream listens on url http://localhost:5005/stocks for JSON messages with format:

{
  "event": {
    "value1": 3,
    "value2": 4
  }
}

and when events arrive it maps to AddStream events and pass them to query query1 for processing. The query results produced on ResultStream are sent as a response via http-service-response sink with format:

{
  "event": {
    "results": 7
  }
}

Here the request and response are correlated by passing the messageId produced by the http-service to the respective http-service-response sink.