Merge pull request #613 from danielgtaylor/unwrap-response-writer

feat: unwrap resp for better deadline/flush SSE support

examples/sse/main.go

@@ -22,16 +22,19 @@ import (
 
 	"github.com/danielgtaylor/huma/v2"
 	"github.com/danielgtaylor/huma/v2/adapters/humachi"
+	"github.com/danielgtaylor/huma/v2/adapters/humagin"
 	"github.com/danielgtaylor/huma/v2/humacli"
 	"github.com/danielgtaylor/huma/v2/sse"
+	"github.com/gin-gonic/gin"
 	"github.com/go-chi/chi/v5"
 
 	_ "github.com/danielgtaylor/huma/v2/formats/cbor"
 )
 
 // Options for the CLI.
 type Options struct {
-	Port int `help:"Port to listen on" default:"8888"`
+	Port   int    `help:"Port to listen on" default:"8888"`
+	Router string `help:"Router to use" enum:"chi,gin" default:"chi"`
 }
 
 // First, define your SSE message types. These can be any struct you want and
@@ -126,8 +129,20 @@ func main() {
 	// Create a CLI app which takes a port option.
 	cli := humacli.New(func(hooks humacli.Hooks, options *Options) {
 		// Create a new router & API
-		router := chi.NewMux()
-		api := humachi.New(router, huma.DefaultConfig("My API", "1.0.0"))
+		var router http.Handler
+		var api huma.API
+
+		if options.Router == "chi" {
+			r := chi.NewMux()
+			api = humachi.New(r, huma.DefaultConfig("My API", "1.0.0"))
+			router = r
+		} else if options.Router == "gin" {
+			r := gin.New()
+			api = humagin.New(r, huma.DefaultConfig("My API", "1.0.0"))
+			router = r
+		} else {
+			panic("Unknown router " + options.Router)
+		}
 
 		// Create a producer to generate messages for clients.
 		p := Producer{Cancel: make(chan bool, 1)}

sse/sse.go

@@ -24,6 +24,14 @@ func deref(t reflect.Type) reflect.Type {
 	return t
 }
 
+type unwrapper interface {
+	Unwrap() http.ResponseWriter
+}
+
+type writeDeadliner interface {
+	SetWriteDeadline(time.Time) error
+}
+
 // Message is a single SSE message. There is no `event` field as this is
 // handled by the `eventTypeMap` when registering the operation.
 type Message struct {
@@ -119,9 +127,41 @@ func Register[I any](api huma.API, op huma.Operation, eventTypeMap map[string]an
 				ctx.SetHeader("Content-Type", "text/event-stream")
 				bw := ctx.BodyWriter()
 				encoder := json.NewEncoder(bw)
+
+				// Get the flusher/deadliner from the response writer if possible.
+				var flusher http.Flusher
+				flushCheck := bw
+				for {
+					if f, ok := flushCheck.(http.Flusher); ok {
+						flusher = f
+						break
+					}
+					if u, ok := flushCheck.(unwrapper); ok {
+						flushCheck = u.Unwrap()
+					} else {
+						break
+					}
+				}
+
+				var deadliner writeDeadliner
+				deadlineCheck := bw
+				for {
+					if d, ok := deadlineCheck.(writeDeadliner); ok {
+						deadliner = d
+						break
+					}
+					if u, ok := deadlineCheck.(unwrapper); ok {
+						deadlineCheck = u.Unwrap()
+					} else {
+						break
+					}
+				}
+
 				send := func(msg Message) error {
-					if d, ok := bw.(interface{ SetWriteDeadline(time.Time) error }); ok {
-						d.SetWriteDeadline(time.Now().Add(WriteTimeout))
+					if deadliner != nil {
+						if err := deadliner.SetWriteDeadline(time.Now().Add(WriteTimeout)); err != nil {
+							fmt.Println("warning: unable to set write deadline: " + err.Error())
+						}
 					} else {
 						fmt.Println("warning: unable to set write deadline")
 					}
@@ -155,8 +195,8 @@ func Register[I any](api huma.API, op huma.Operation, eventTypeMap map[string]an
 						return err
 					}
 					bw.Write([]byte("\n"))
-					if f, ok := bw.(http.Flusher); ok {
-						f.Flush()
+					if flusher != nil {
+						flusher.Flush()
 					} else {
 						fmt.Println("error: unable to flush")
 						return fmt.Errorf("unable to flush: %w", http.ErrNotSupported)

sse/sse_test.go

@@ -28,7 +28,8 @@ type UserCreatedEvent UserEvent
 type UserDeletedEvent UserEvent
 
 type DummyWriter struct {
-	writeErr error
+	writeErr    error
+	deadlineErr error
 }
 
 func (w *DummyWriter) Header() http.Header {
@@ -41,8 +42,17 @@ func (w *DummyWriter) Write(p []byte) (n int, err error) {
 
 func (w *DummyWriter) WriteHeader(statusCode int) {}
 
-func (w *DummyWriter) SetWriteDeadline(t time.Time) error {
-	return nil
+func (w *DummyWriter) Unwrap() http.ResponseWriter {
+	return &WrappedDeadliner{deadlineErr: w.deadlineErr}
+}
+
+type WrappedDeadliner struct {
+	http.ResponseWriter
+	deadlineErr error
+}
+
+func (w *WrappedDeadliner) SetWriteDeadline(t time.Time) error {
+	return w.deadlineErr
 }
 
 func TestSSE(t *testing.T) {
@@ -105,4 +115,9 @@ data: {"error": "encode error: json: unsupported type: chan int"}
 	w = &DummyWriter{}
 	req, _ = http.NewRequest(http.MethodGet, "/sse", nil)
 	api.Adapter().ServeHTTP(w, req)
+
+	// Test inability to set write deadline due to error doesn't panic
+	w = &DummyWriter{deadlineErr: errors.New("whoops")}
+	req, _ = http.NewRequest(http.MethodGet, "/sse", nil)
+	api.Adapter().ServeHTTP(w, req)
 }