502 Bad Gateway with built in CODE server - shows lool instead of cool

[n-greene]

I am running NC 27.02 php8.1.2 pgsql15.4 with ssl termination in haproxy.
OS Linux 5.15.0-79-generic x86_64
Ubuntu 22.04.3 LTS
NC Office 8.1.1 CODE server 23.5.202

I am using the built in CODE server and currently it opens documents every third or fourth try.

I have wrestled with my Apache2 Virtualhost conf to get to this point. I was previously running Office/Built in CODE behind an NGINX reverse proxy with ssl termination and did not need any proxy directives in virtual host. I cannot be exact but it seemed like the trouble started before I switched over to Haproxy but I would not be able to pinpoint the versions of CODE and NC Office that changed with (last 3 months estimate) but I do keep everything updated at all times, for better or for worse.

Suffice it to say that what I have put in the current virtual host has been sufficient to get NC office to launch, at all, but not consistently or reliably. I would like to see the NC Office/Built in CODE working as it was.

In NC logs the following error shows up periodically, it references req=/lool/convert-to/png which I believe is an obsolete setting for CODE, being superceded by cool so I am not sure why this is still being referenced as I do have an up to date install.

[richdocuments] Info: GuzzleHttp\Exception\ServerException: Server error: POST https://xxx.xxxx.net/apps/richdocumentscode/proxy.php?req=/lool/convert-to/png` resulted in a 502 Bad Gateway response:

502 Bad Gateway

The server returned an invalid or incomplete response.

at <>

0. /var/www/html/nextcloud/3rdparty/guzzlehttp/guzzle/src/Middleware.php line 69
   GuzzleHttp\Exception\RequestException::create("*** sensitive parameters replaced ***")
1. /var/www/html/nextcloud/3rdparty/guzzlehttp/promises/src/Promise.php line 204
   GuzzleHttp\Middleware::GuzzleHttp{closure}("*** sensitive parameters replaced ***")
2. /var/www/html/nextcloud/3rdparty/guzzlehttp/promises/src/Promise.php line 153
   GuzzleHttp\Promise\Promise::callHandler()
3. /var/www/html/nextcloud/3rdparty/guzzlehttp/promises/src/TaskQueue.php line 48
   GuzzleHttp\Promise\Promise::GuzzleHttp\Promise{closure}("*** sensitive parameters replaced ***")
4. /var/www/html/nextcloud/3rdparty/guzzlehttp/promises/src/Promise.php line 248
   GuzzleHttp\Promise\TaskQueue->run()
5. /var/www/html/nextcloud/3rdparty/guzzlehttp/promises/src/Promise.php line 224
   GuzzleHttp\Promise\Promise->invokeWaitFn()
6. /var/www/html/nextcloud/3rdparty/guzzlehttp/promises/src/Promise.php line 269
   GuzzleHttp\Promise\Promise->waitIfPending()
7. /var/www/html/nextcloud/3rdparty/guzzlehttp/promises/src/Promise.php line 226
   GuzzleHttp\Promise\Promise->invokeWaitList()
8. /var/www/html/nextcloud/3rdparty/guzzlehttp/promises/src/Promise.php line 62
   GuzzleHttp\Promise\Promise->waitIfPending()
9. /var/www/html/nextcloud/3rdparty/guzzlehttp/guzzle/src/Client.php line 187
   GuzzleHttp\Promise\Promise->wait()
10. /var/www/html/nextcloud/lib/private/Http/Client/Client.php line 297
    GuzzleHttp\Client->request()
11. /var/www/html/nextcloud/apps/richdocuments/lib/Preview/Office.php line 90
    OC\Http\Client\Client->post()
12. /var/www/html/nextcloud/lib/private/Preview/ProviderV1Adapter.php line 53
    OCA\Richdocuments\Preview\Office->getThumbnail()
13. /var/www/html/nextcloud/lib/private/Preview/GeneratorHelper.php line 64
    OC\Preview\ProviderV1Adapter->getThumbnail()
14. /var/www/html/nextcloud/lib/private/Preview/Generator.php line 397
    OC\Preview\GeneratorHelper->getThumbnail()
15. /var/www/html/nextcloud/lib/private/Preview/Generator.php line 373
    OC\Preview\Generator->generateProviderPreview()
16. /var/www/html/nextcloud/lib/private/Preview/Generator.php line 166
    OC\Preview\Generator->getMaxPreview()
17. /var/www/html/nextcloud/lib/private/Preview/Generator.php line 116
    OC\Preview\Generator->generatePreviews()
18. /var/www/html/nextcloud/lib/private/PreviewManager.php line 192
    OC\Preview\Generator->getPreview()
19. /var/www/html/nextcloud/core/Controller/PreviewController.php line 144
    OC\PreviewManager->getPreview()
20. /var/www/html/nextcloud/core/Controller/PreviewController.php line 113
    OC\Core\Controller\PreviewController->fetchPreview()
21. /var/www/html/nextcloud/lib/private/AppFramework/Http/Dispatcher.php line 230
    OC\Core\Controller\PreviewController->getPreviewByFileId()
22. /var/www/html/nextcloud/lib/private/AppFramework/Http/Dispatcher.php line 137
    OC\AppFramework\Http\Dispatcher->executeController()
23. /var/www/html/nextcloud/lib/private/AppFramework/App.php line 183
    OC\AppFramework\Http\Dispatcher->dispatch()
24. /var/www/html/nextcloud/lib/private/Route/Router.php line 315
    OC\AppFramework\App::main()
25. /var/www/html/nextcloud/lib/base.php line 1071
    OC\Route\Router->match()
26. /var/www/html/nextcloud/index.php line 36
    OC::handleRequest()

GET /index.php/core/preview?forceIcon=0&a=0&c=07044c766b4e1f3ba7c2e17f201ee4f3&x=250&y=250&fileId=1270797
from 192.168.10.1 by xxxat 2023-08-16T13:00:39+00:00'

My Apache 2 virtual host is configured:

`<VirtualHost *:80>
ServerName xxx.xxxx.net
ServerAdmin [email protected]
DocumentRoot /var/www/html/nextcloud
ErrorLog ${APACHE_LOG_DIR}/error.log
CustomLog ${APACHE_LOG_DIR}/access.log combined

RequestHeader set X-FORWARDED-PROTOCOL https
RequestHeader set X-Forwarded-Ssl on

AllowEncodedSlashes NoDecode
ProxyAddHeaders On
Proxypreservehost On
LimitRequestBody 0
KeepAlive On

Redirect 301 /.well-known/carddav https:/xxx.xxxxx.nett/remote.php/dav
Redirect 301 /.well-known/caldav https://xxx.xxxxx.net/remote.php/dav
Redirect 301 /.well-known/webfinger https://xxx.xxxxx.net/index.php/.well-known/webfinger
Redirect 301 /.well-known/nodeinfo https://xxx.xxxxx.net/index.php/.well-known/nodeinfo
`

The Redirect 301 entries are for carddav and caldav to work behind haproxy, which they do.

Remedies attempted, based on searching for solutions:

I have tried setting WOPI to 0.0.0.0/0
I have tried remove/reinstall Built in CODE and NC Office, whilst running sudo killall coolswd in the interim
I have tried selecting 'Use your own server' and then clicking back on the 'Use the built-in CODE' button which results in being able to open a document, but then lapses into failing to launch Nextcloud office. If I try opening the document three or four times it will open. I can see previews of the document type and when I do get a document open I can save.

The apache2 virtual host settings are probably going to upset someone, but I just went through ANYTHING I could find on this subject and tried it out - obviously explicit reverse proxy directives break apache because I am not running CODE on a separate server - I just left in stuff which did not throw an error on restarting apache2 - feel free to comment on unnecessary entries, I just could not find any documentation explicitly for built in CODE server.