Intermittent Empty Responses with HTTP 200 from myopenHAB Sitemap API

[TheNinth7]

I'm currently testing my openHAB for Garmin app, which regularly polls the sitemap API via myopenHAB.org. Both I and other users have noticed that, occasionally - and somewhat regularly - the API returns an HTTP 200 (OK) status, but with no content in the response body.

I’ve reproduced this behavior outside of the Garmin app as well, simply by repeatedly requesting the same URL in Firefox:

https://home.myopenhab.org/rest/sitemaps/garmin_demo

(garmin_demo is the sitemap name.)

Below are the HTTP request and response headers captured during one of these empty responses (authorization info removed).

I initially suspected rate limiting, but I’d expect the server to respond with a 429 Too Many Requests or 503 Service Unavailable in that case - not a 200 OK.

GET /rest/sitemaps/garmin_demo HTTP/1.1
Host: home.myopenhab.org
User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:138.0) Gecko/20100101 Firefox/138.0
Accept: text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8
Accept-Language: en-GB,en;q=0.5
Accept-Encoding: gzip, deflate, br, zstd
Authorization: Basic REMOVED
Connection: keep-alive
Cookie: __utma=211485577.443714860.1715675546.1732260971.1746011753.6; __utmz=211485577.1715675546.1.1.utmcsr=(direct)|utmccn=(direct)|utmcmd=(none); _ga=GA1.2.443714860.1715675546; _ga_BGSSTP9020=GS1.2.1746011173.1.1.1746011173.0.0.0; X-OPENHAB-AUTH-HEADER=true; CloudServer=10.11.0.31%3A3000
Upgrade-Insecure-Requests: 1
Sec-Fetch-Dest: document
Sec-Fetch-Mode: navigate
Sec-Fetch-Site: none
Sec-Fetch-User: ?1
Priority: u=0, i

HTTP/1.1 200 OK
Server: nginx/1.18.0 (Ubuntu)
Date: Thu, 01 May 2025 18:24:10 GMT
Content-Length: 0
Connection: keep-alive
X-Powered-By: Express
Set-Cookie: CloudServer=10.11.0.31%3A3000; Max-Age=900; Path=/; Expires=Thu, 01 May 2025 18:39:10 GMT; HttpOnly
Set-Cookie: X-OPENHAB-AUTH-HEADER=true; Path=/

[sjonez]

I also see this frequently, and I believe it's also the reason I often see openhab-exposed items switching between online and unresponsive in the Alexa app. Whenever I see that happening in Alexa, if I test an API call to an item (e.g. https://home.myopenhab.org/rest/items/ItemName) I get intermittent empty 200 responses. Restarting the cloud binding seems to solve it temporarily (but not for long)

[TheNinth7]

I have similar issues with Alexa, as it seems have others:

https://community.openhab.org/t/alexa-keeps-complaining-about-device-is-not-responding-but-everything-is-working/

Could the empty 200 responses be the root cause of this?

[sjonez]

I have similar issues with Alexa, as it seems have others:

https://community.openhab.org/t/alexa-keeps-complaining-about-device-is-not-responding-but-everything-is-working/

Could the empty 200 responses be the root cause of this?

Yes, I'm fairly certain it is. From what I've observed when Alexa is flipping between responsive/unresponsive for an exposed item, manual requests via the API are also flipping between normal and empty 200 responses.

Interestingly, I've had the cloud binding in trace logging for the past few days and haven't seen the issue happen at all. Not sure if it's a coincidence or if the logging itself is helping somehow.