Hey, is there a way to set the base url that RPC w...

# kilua

[Corey]

Hey, is there a way to set the base url that RPC will call? by default it must use relative paths so when we send a client side RPC call from https://localhost:3000/something/something it sends the request to /something/rpc/...

[Robert Jaros]

Hello

[Robert Jaros]

It can be set using rcp_url_prefix global javascript variable, e.g. in the main index.html file, before adding application bundle file:

<script>window["rpc_url_prefix"] = `/something/something';</script>

[Corey]

Sorry, I meant it should always send the request to http://localhost:3010/rpc/ so its using the absolute url

[Robert Jaros]

I don't know if I understand so let me explain from the beginning (I should put this in the docs). By default all RPC endpoints are called by using relative paths (rpc/*). It should work fine for most simple cases, where the app is deployed on / and when it's deployed using some custom path like /something. But it doesn't always work. One case is when the backend is published separately from the frontend (even on different hosts). The other case is when the application uses history api client routing (nice urls like /some/other/route) - the app will try to call /some/other/rpc/* endpoints and of course it will fail. Such app can also be deployed using a custom /something path, which makes things even harder.

[Robert Jaros]

The general solution for these problems is setting rpc_url_prefix global variable. Its value is read as globalThis.jsGet("rpc_url_prefix"), so it can be set in different ways (externally using window["rpc_url_prefix"] or in Kotlin code using globalThis.jsSet()). The value of the variable (if set) is added to the path called by the RPC client as $urlPrefix/rpc. The value can be both absolute and relative.

[Robert Jaros]

So, going back to typical cases. When the backend is deployed separately, you can use the full URL address (window["rpc_url_prefix"] = "<http://example.com/backend_path>").

[Corey]

ahhhh right, my apologies. when I looked at the code and saw how rpc_url_prefix was used I thought it still used the relative url + rpc_url_prefix and then /rpc. but using window["rpc_url_prefix"] = "<http://example.com/backend_path>" is exactly what I was after

[Robert Jaros]

When the application is using client routing but is deployed on / you can use window["rpc_url_prefix"] = ""; - it will make all RPC calls starting with /.

[Robert Jaros]

When the app is also deployed on different path (/something) you need to know (or guess) this path and set window["rpc_url_prefix"] = "/something".

[Robert Jaros]

I have apps, which can be deployed both on / or using specific path /something and I'm using such this code in my `index.html`:

var prefix = "";
        if (window.location.pathname.startsWith("/something/")) prefix = "/something";
        window["rpc_url_prefix"] = prefix;

[Robert Jaros]

Copied to the guide: https://kilua.gitbook.io/kilua-rpc-guide/frontend-side#rpc-endpoint-paths

[Corey]

appreciate it!