Plugins | Response transformer broken on Kong 2.8.1.4

[PalAditya]

Is there an existing issue for this?

• I have searched the existing issues

Kong version ($ kong version)

2.8.1.4

Current Behavior

The response transformer plugin breaks on Kong 2.8.1.4 if there's a string response.

Sample:

- name: response-transformer
  config:
    remove:
       json:
          - "xyz"

Same issue does not occur with response-transformer-advanced

Expected Behavior

The plugin shouldn't crash kong, as the response is plain string and not json.

Steps To Reproduce

- Use Kong 2.8.1.4 in DBLess Mode
- Create any route which points to an upstream that returns a plain string (e.g: "Hello, World")
- Apply response-transformer on the plugin with above config
- Kong will crash.

Anything else?

OS: Rhel8

[VicYP]

@PalAditya Thank you for your investigation. We will give it a try and this one needs to be fixed.

[samugi]

hello @PalAditya, I think I was able to replicate this but there are a couple of details I'd like to clarify:

• I could only replicate this by having an upstream endpoint return an invalid response body: the upstream API I used returned Content-Type: application/json; while the body was actually text. I could not replicate this with an upstream API that would return Content-Type: text/plain; correctly
• Kong is not crashing, rather when this happens the connection with the client is closed without a response, no worker is restarted and other requests to valid endpoints keep working

Could you confirm the issue I reproduced reflects your findings?

[PalAditya]

Hi @samugi , that's right
However, I'm also observing the same behavior if no content-type is set at all.

[samugi]

resolved by #9463