An example of writing a chat server using OWIN and F# Agents. See http://tomasp.net/blog/education-and-agents-talks.aspx

OwinChat.fsx

let root = @"C:\demos\FSharp.Agents\Demo.ChatServer\"
let cts = new CancellationTokenSource()

Owin.Extensions.Application.Start
 ("http://localhost:8082/", (fun request -> async {
  match request.Path with  // Path is an extension on IRequest to retrieve the path without the query string.
  | "/post" ->
      // Send message to the chat room
      let! body = request.AsyncReadBody()  // Extension that asynchronously reads the request body.
      room.SendMessage(body)  // room is an instance wrapping a F# MailboxProcessor<_>
      Owin.Extensions.Response.Reply("OK")
  | "/chat" -> 
      // Get messages from the chat room (asynchronously!)
      let! text = room.AsyncGetContent()
      Owin.Extensions.Response.Reply(text)
  | s ->
      // Handle an ordinary file request
      let file = 
        root + (if s = "/" then "chat.html" else s.ToLower())
      if File.Exists(file) then 
        let typ = contentTypes.[Path.GetExtension(file)]
        Owin.Extensions.Response.Reply(typ, File.ReadAllBytes(file))
      else 
        Owin.Extensions.Response.Reply(sprintf "File not found: %s" file) }),
   cts.Token)

cts.Cancel()