Display a value from an external webservice in the header

Kia ora folks,
Just a need a (hopefully) quick pointer in the right direction. I want to retrieve a value (json) from an external URL and display it in the header.
The webservice is public and just returns a single value like this:

{
    "CounterValue": 25
}

I’m running discourse self-hosted, standard install.
I’m not too concerned if the call is made client side or server side, the webservice is public.
What’s the best way to approach this. Would I need a plug-in, a theme component? Or can this be done out of the box?

Cheers
Rhys

A theme component is easier to install and maintain. It would make the remote ajax call at least for every user (if it doesn’t change, though, I think one call in an intitializer wouldnt’ be that big a deal).

A plugin might allow you to cache the result and just add it to the serializer.

This does nearly everything you’d want. Just fork it, substitute the web service and tailor the presentation to suit your needs:

Brilliant, thank you both. That’s got me underway.