Fix oak middleware (#284)

Author: ije

server/oak.ts

@@ -1,5 +1,6 @@
 import type { Context } from 'https://deno.land/x/[email protected]/context.ts'
 import type { Middleware } from 'https://deno.land/x/[email protected]/middleware.ts'
+import { NativeRequest } from 'https://deno.land/x/[email protected]/http_server_native.ts'
 import { Application } from './app.ts'
 import { Server } from './server.ts'
 
@@ -8,7 +9,12 @@ export function alephOak(app: Application): Middleware {
   const server = new Server(app)
 
   return (ctx: Context) => {
-    server.handle(ctx.request.originalRequest)
-    ctx.respond = false
+    const { originalRequest } = ctx.request
+    if (originalRequest instanceof NativeRequest) {
+      ctx.throw(500, 'Aleph.js doesn\'t support NativeRequest yet')
+    } else {
+      server.handle(originalRequest)
+      ctx.respond = false
+    }
   }
 }