distinguish Upgrader.Upgrade from Upgrade

doc.go

@@ -6,9 +6,9 @@
 //
 // Overview
 //
-// The Conn type represents a WebSocket connection. A server application uses
-// the Upgrade function from an Upgrader object with a HTTP request handler
-// to get a pointer to a Conn:
+// The Conn type represents a WebSocket connection. Within the context of an
+// HTTP request handler, a server application calls the Upgrade method of an
+// Upgrader instance obtaining a pointer to a Conn:
 //
 //  var upgrader = websocket.Upgrader{
 //      ReadBufferSize:  1024,
@@ -147,9 +147,15 @@
 //      CheckOrigin: func(r *http.Request) bool { return true },
 //  }
 //
-// The deprecated Upgrade function does not enforce an origin policy. It's the
-// application's responsibility to check the Origin header before calling
-// Upgrade.
+// We recommend the upgrader.Upgrade method to perform an upgrade
+// from an HTTP connection to a websocket connection. This method performs
+// origin policy checking using the CheckOrigin field associated with the
+// Upgrader instance.
+//
+// By contrast, the deprecated package-level Upgrade function
+// does not perform origin checking. In this case is the application's
+// responsibility to manually check the Origin header before calling the
+// package-level Upgrade function.
 //
 // Compression EXPERIMENTAL
 //

server.go

@@ -228,12 +228,14 @@ func (u *Upgrader) Upgrade(w http.ResponseWriter, r *http.Request, responseHeade
 	return c, nil
 }
 
+// DEPRECATED - use websocket.Upgrader instead.
+//
 // Upgrade upgrades the HTTP server connection to the WebSocket protocol.
 //
-// This function is deprecated, use websocket.Upgrader instead.
-//
-// The application is responsible for checking the request origin before
-// calling Upgrade. An example implementation of the same origin policy is:
+// Note that the application is responsible for checking the request origin
+// before calling Upgrade. This is not done automatically as with the use of the
+// Upgrader.Upgrade method. An example implementation of the same origin policy
+// check is:
 //
 //	if req.Header.Get("Origin") != "http://"+req.Host {
 //		http.Error(w, "Origin not allowed", 403)