Proxmox VE API and CORS problem

[karnalta]

Hello,

I am trying to query the Proxmox API via an API key from a Blazor Webassembly app.

I can't seem to get it work, I am always denied via CORS.



I did try the two proposed solutions from this thread but none of them seem to work for me.

I am quite new to web frontend development, so all these CORS issues are still a bit unclear to me..

As I understand it, it's not really a Proxmox issue, as I can query the API via a software like Postman. I am not certain of who reject the query exactly, the browser itself ? The WASM client app ?

Any help would be appreciate !

 

[Chris]

Hello,

I am trying to query the Proxmox API via an API key from a Blazor Webassembly app.

I can't seem to get it work, I am always denied via CORS.

View attachment 68072

I did try the two proposed solutions from this thread but none of them seem to work for me.

I am quite new to web frontend development, so all these CORS issues are still a bit unclear to me..

As I understand it, it's not really a Proxmox issue, as I can query the API via a software like Postman. I am not certain of who reject the query exactly, the browser itself ? The WASM client app ?

Any help would be appreciate !

Hi,
CORS is enforced by the browser, limiting from which domains the browser should allow loading resources from, see https://developer.mozilla.org/en-US/docs/Web/HTTP/CORS So in your case, since your webapp runs as localhost, the browser is blocking the requests to the domain the api is running on, in particular [1].

As stated by @fabian [0] in the other thread, you will have to setup a reverse proxy (e.g. nginx) which adds the required headers to allow the additional domains and perform the api requests via the proxy instead.

[0] https://forum.proxmox.com/threads/api-calls-from-webapp.81479/post-375842
[1] https://developer.mozilla.org/en-US/docs/Glossary/Preflight_request