[Filebeat] httpjson - cannot send empty json object in body

[andrewkroh]

I want to be able to send an empty object in the body of a POST request. This is what my desired request would look like.

POST / HTTP/1.1
Host: localhost:8888
User-Agent: Elastic-Filebeat/8.7.0 (darwin; arm64; 2fc3e81eb31eefeb973bbffbf6d48e11327f9019; 2022-12-06 12:42:07 +0000 UTC)
Content-Length: 2
Accept: application/json
Content-Type: application/json
Accept-Encoding: gzip
Connection: close

{}

But the input always writes an empty body (content-length 0) instead of an empty object {} when I try to configure this. I see there is an explicit empty check performed when encoding the output. ¹

    # WRONG: generates empty body
    request.body: {}

    # ERROR: cannot target body directly
    request.transforms:
      - set:
          target: body
          value_type: json
          value: '{}'

    # WRONG: generates empty body
    request.transforms:
      - set:
          target: body.foo
          value: 'bar'
      - delete:
          target: body.foo

Footnotes

1. https://github.com/elastic/beats/blob/ba3bce42590dbf722061d7d92bfdb0bd903e9014/x-pack/filebeat/input/httpjson/encoding.go#L106-L108 ↩

[elasticmachine]

Pinging @elastic/security-external-integrations (Team:Security-External Integrations)

[botelastic]

Hi!
We just realized that we haven't looked into this issue in a while. We're sorry!

We're labeling this issue as Stale to make it hit our filters and make sure we get back to it as soon as possible. In the meantime, it'd be extremely helpful if you could take a look at it as well and confirm its relevance. A simple comment with a nice emoji will be enough :+1.
Thank you for your contribution!

[elasticmachine]

Pinging @elastic/security-service-integrations (Team:Security-Service Integrations)