update according to reviewer's advice

Signed-off-by: wenfeng <sxian.wang@gmail.com>

samples/http/receiver-result/main.go

@@ -1,5 +1,5 @@
 /*
- Copyright 2021 The CloudEvents Authors
+ Copyright 2022 The CloudEvents Authors
  SPDX-License-Identifier: Apache-2.0
 */
 

samples/http/sender-protobuf/main.go

@@ -42,8 +42,9 @@ func main() {
 			var httpResult *cehttp.Result
 			if cloudevents.ResultAs(res, &httpResult) {
 				log.Printf("Sent %d with status code %d", i, httpResult.StatusCode)
+			} else {
+				log.Printf("Send did not return an HTTP response: %s", res)
 			}
-			log.Printf("Send did not return an HTTP response: %s", res)
 		}
 	}
 }

samples/http/sender/main.go

@@ -9,6 +9,7 @@ import (
 	"context"
 	"fmt"
 	"log"
+	"net/http"
 
 	cloudevents "github.com/cloudevents/sdk-go/v2"
 	cehttp "github.com/cloudevents/sdk-go/v2/protocol/http"
@@ -41,9 +42,15 @@ func main() {
 			log.Printf("Failed to send: %v", res)
 		} else {
 			var httpResult *cehttp.Result
-			cloudevents.ResultAs(res, &httpResult)
-			log.Printf("Sent %d with status code %d, error: %s", i, httpResult.StatusCode,
-				fmt.Errorf(httpResult.Format, httpResult.Args))
+			if cloudevents.ResultAs(res, &httpResult) {
+				var err error
+				if httpResult.StatusCode != http.StatusOK {
+					err = fmt.Errorf(httpResult.Format, httpResult.Args...)
+				}
+				log.Printf("Sent %d with status code %d, error: %v", i, httpResult.StatusCode, err)
+			} else {
+				log.Printf("Send did not return an HTTP response: %s", res)
+			}
 		}
 	}
 }

v2/protocol/http/protocol.go

@@ -391,10 +391,8 @@ func (p *Protocol) ServeHTTP(rw http.ResponseWriter, req *http.Request) {
 		}
 
 		rw.WriteHeader(status)
-		if errMsg != "" {
-			if _, err := rw.Write([]byte(errMsg)); err != nil {
-				return err
-			}
+		if _, err := rw.Write([]byte(errMsg)); err != nil {
+			return err
 		}
 		return nil
 	}