WOPI host and WOPI client example

Question

I am a bit confused about WOPI host and WOPI client. Can anyone tell me exactly the meaning of above 2 terms. I want to know what exactly means WOPI host (either my web application or a WOPI server on Microsoft side) and same for WOPI client.

Solution

WOPI host = WOPI server = a web API that serves files to WOPI client

WOPI client = an application that is able to edit files served by WOPI host

The two communicate via MS-WOPI protocol that is described here.

Example implementations:

• WOPI host - SharePoint
• WOPI client - Office Web Apps (Office Online Server)

A typical scenario is that you want to enable your application to edit files in Word/Excel... In that case, you need to implement a WOPI host - an endpoint which the WOPI client (OWA) will talk to. Implementing such a host is described here. You can take a look at existing projects on GitHub - marx-yu's implementation using HttpListener, or mine using ASP.NET Core 3.1.