Installing Harp for ExApps: Can't Connect from Nextcloud

[That_Dude]

The Basics

• Nextcloud Server version (e.g., 29.x.x):
  • 31.0.4
• Operating system and version (e.g., Ubuntu 24.04):
  • Ubuntu 24.04.2
• Web server and version (e.g, Apache 2.4.25):
  • nginx/1.27.5
• Reverse proxy and version _(e.g. nginx 1.27.2)
  • Caddy 2.6.2
• PHP version (e.g, 8.3):
  • 31.0.4.1
• Is this the first time you’ve seen this error? (Yes / No):
  • Yes
• When did this problem seem to first start?
  • I am installing
• Installation method (e.g. AlO, NCP, Bare Metal/Archive, etc.)
  • Docker
• Are you using CloudfIare, mod_security, or similar? (Yes / No)
  • Yes but proxying is off

Summary of the issue you are facing:

I am interested in installing ExApps and I have been following the documentation from Nextcloud as well as the documenation on GitHub. I have a working docker container for appapi-harp that is bound to 127.0.0.1:8070. They can also communicate over a docker network (nextcloud_network). When I try to add harp API to my nextcloud daemons, I get an error. When checking the logs it mentions that it cannot curl appapi-harp:8070/v1.41/_ping. My understanding is that harp is meant to serve this page, but instead I get a 404 error. When I look into the docker container logs, it is actually getting the request but says Invalid request path.

I am a bit of a newbie here and just trying to dive in the deep end. With that caveat, my understanding is that nextcloud expects the harp container to serve /v1.41/_ping but the harp container isn’t ready for it. Is there something I am missing here? I have looked around the internet and not really seen anything on this, and I am also not reallly sure what I could have misconfigured if the harp container isn’t serving a page it should be serving.

Admin Console AppAPI Screen

Log entries

Nextcloud Admin Console Logs

So I looked to the admin console.

 ConnectException cURL error 7: Failed to connect to appapi-harp port 8070 after 0 ms: Couldn't connect to server (see https://curl.haxx.se/libcurl/c/libcurl-errors.html) for http://appapi-harp:8070/v1.41/_ping

nextcloud-app Docker Container

I can reach the appapi-harp container from inside of the nextcloud-app container (running nextcloud fpm). But it is getting back a 404.

root@8c03fc6ccbf4:/var/www/html# curl -v http://appapi-harp:8780/v1.41/_ping
*   Trying 172.19.0.8:8780...
* Connected to appapi-harp (172.19.0.8) port 8780 (#0)
> GET /v1.41/_ping HTTP/1.1
> Host: appapi-harp:8780
> User-Agent: curl/7.88.1
> Accept: */*
>
< HTTP/1.1 404 Not Found
< content-length: 13
< content-type: text/plain
<
* Connection #0 to host appapi-harp left intact
404 Not Found

appapi-harp Docker Container Logs

So the appapi-harp container is seeing the request, but it isn’t formatted in such a way that it knows what to do with it? Or maybe somehow I have more configurations to do on the container so it can serve this page.

[2025-05-28T19:22:08+0000] [ERROR] Invalid request path, cannot find AppID: /v1.41/_ping

[jtr]

To my knowledge you’d need to be running v32 (i.e. a development stack):

Cannot connect from nextcloud instance

[That_Dude]

@jtr
Thank you . I should have dug deeper on GitHub. Now I need to decide if playing with this is worth setting up a development stack…