fstthttp,interal,x: Add v2 versions of Handoff Websocket and Fanout (#210)

Author: dgryski

fsthttp/request.go

@@ -1087,6 +1087,30 @@ type DecompressResponseOptions struct {
 	Gzip bool
 }
 
+// HandoffWebsocket passes the WebSocket directly to a backend.
+//
+// This can only be used on services that have the WebSockets feature
+// enabled and on requests that are valid WebSocket requests.  The sending
+// completes in the background.
+//
+// Once this method has been called, no other response can be sent to this
+// request, and the application can exit without affecting the send.
+func (r *Request) HandoffWebsocket(backend string) error {
+	return r.downstream.req.HandoffWebsocket(backend)
+}
+
+// HandoffFanout passes the request through the Fanout GRIP proxy and on to
+// a backend.
+//
+// This can only be used on services that have the Fanout feature enabled.
+//
+// The sending completes in the background. Once this method has been
+// called, no other response can be sent to this request, and the
+// application can exit without affecting the send.
+func (r *Request) HandoffFanout(backend string) error {
+	return r.downstream.req.HandoffWebsocket(backend)
+}
+
 // nopCloser is functionally the same as io.NopCloser, except that we
 // can get to the underlying io.Reader.
 type nopCloser struct {

internal/abi/fastly/hostcalls_noguest.go

@@ -233,6 +233,14 @@ func (r *HTTPRequest) SetFramingHeadersMode(manual bool) error {
 	return fmt.Errorf("not implemented")
 }
 
+func (r *HTTPRequest) HandoffWebsocket(backend string) error {
+	return fmt.Errorf("not implemented")
+}
+
+func (r *HTTPRequest) HandoffFanout(backend string) error {
+	return fmt.Errorf("not implemented")
+}
+
 type HTTPRequestPromise struct{}
 
 func DownstreamNextRequest(opts *NextRequestOptions) (*HTTPRequestPromise, error) {

internal/abi/fastly/http_guest.go

@@ -16,14 +16,35 @@ import (
 // (module $fastly_http_req
 
 // witx:
+
+// (@interface func (export "redirect_to_websocket_proxy_v2")
 //
-// (@interface func (export "redirect_to_websocket_proxy")
-//
+//	(param $h $request_handle)
 //	(param $backend_name string)
 //	(result $err (expected (error $fastly_status)))
 //
 // )
 //
+//go:wasmimport fastly_http_req redirect_to_websocket_proxy_v2
+//go:noescape
+func fastlyHTTPReqRedirectToWebsocketProxyV2(
+	r requestHandle,
+	backendData prim.Pointer[prim.U8], backendLen prim.Usize,
+) FastlyStatus
+
+func (r *HTTPRequest) HandoffWebsocket(backend string) error {
+	backendBuffer := prim.NewReadBufferFromString(backend).Wstring()
+
+	if err := fastlyHTTPReqRedirectToWebsocketProxyV2(
+		r.h,
+		backendBuffer.Data, backendBuffer.Len,
+	).toError(); err != nil {
+		return err
+	}
+
+	return nil
+}
+
 //go:wasmimport fastly_http_req redirect_to_websocket_proxy
 //go:noescape
 func fastlyHTTPReqRedirectToWebsocketProxy(
@@ -44,13 +65,34 @@ func HandoffWebsocket(backend string) error {
 
 // witx:
 //
-// (@interface func (export "redirect_to_grip_proxy")
+// (@interface func (export "redirect_to_grip_proxy_v2")
 //
+//	(param $h $request_handle)
 //	(param $backend_name string)
 //	(result $err (expected (error $fastly_status)))
 //
 // )
 //
+//go:wasmimport fastly_http_req redirect_to_grip_proxy_v2
+//go:noescape
+func fastlyHTTPReqRedirectToGripProxyV2(
+	r requestHandle,
+	backendData prim.Pointer[prim.U8], backendLen prim.Usize,
+) FastlyStatus
+
+func (r *HTTPRequest) HandoffFanout(backend string) error {
+	backendBuffer := prim.NewReadBufferFromString(backend).Wstring()
+
+	if err := fastlyHTTPReqRedirectToGripProxyV2(
+		r.h,
+		backendBuffer.Data, backendBuffer.Len,
+	).toError(); err != nil {
+		return err
+	}
+
+	return nil
+}
+
 //go:wasmimport fastly_http_req redirect_to_grip_proxy
 //go:noescape
 func fastlyHTTPReqRedirectToGripProxy(

x/exp/handoff/handoff.go

@@ -1,3 +1,4 @@
+// Deprecated: Use fsthttp.Request.Handoff* methods instead.
 package handoff
 
 import "github.com/fastly/compute-sdk-go/internal/abi/fastly"