[http] buffer size overflow with larger JSON

[binderth]

Trying to receive a JSON from Mowas (https://warnung.bund.de/bbk.mowas/gefahrendurchsagen.json), I get the following WARN in log and the channel is still NULL:

2020-12-15 13:34:33.920 [WARN ] [p.internal.http.HttpResponseListener] - Requesting 'https://warnung.bund.de/bbk.mowas/gefahrendurchsagen.json' (method='GET', content='null') failed: Buffering capacity 2097152 exceeded

The binding doesn't seem to give me the opportunity to define the buffer size.

My Thing and channel definition:

UID: http:url:mowas
label: HTTP Gefahren MoWas
thingTypeUID: http:url
configuration:
  authMode: BASIC
  ignoreSSLErrors: false
  baseURL: https://warnung.bund.de/bbk.mowas/gefahrendurchsagen.json
  refresh: 600
  commandMethod: GET
  contentType: application/json
  timeout: 3000
channels:
  - id: mowasJSON
    channelTypeUID: http:string
    label: JSON von Mowas
    description: ""
    configuration: {}

Expected Behavior

Having a attribute for the binding regarding buffer size if too small

Current Behavior

Binding breaks with a WARN in the log

Possible Solution

Steps to Reproduce (for Bugs)

1. use the URL above as it is currently pretty big JSON response
2. see in log

Context

I try to get the whole JSON to filter out the messages I'd like to use in OH3

Your Environment

• OH3.RC1 on Raspberry PI 3B+
• openHABIAN 1.6

[MHerbst]

As far as I can see, the binding uses a blocking call. This method does not support larger buffers. The Jetty call can be changed to a non-blocking call and then larger buffers are supported. I had a similar problem in the Homematic binding.

[J-N-K]

Nope, not a blocking call, real async processing. For „BufferingResponseListener“ the buffer size is configurable. It was not exposed, though.