Add content-length as part of event notification structure (#6341)

Fixes #6321

cmd/handler-utils.go

@@ -189,6 +189,15 @@ func extractReqParams(r *http.Request) map[string]string {
 	}
 }
 
+// Extract response elements to be sent with event notifiation.
+func extractRespElements(w http.ResponseWriter) map[string]string {
+
+	return map[string]string{
+		"content-length": w.Header().Get("Content-Length"),
+		// Add more fields here.
+	}
+}
+
 // Trims away `aws-chunked` from the content-encoding header if present.
 // Streaming signature clients can have custom content-encoding such as
 // `aws-chunked,gzip` here we need to only save `gzip`.

cmd/notification.go

@@ -449,13 +449,14 @@ func NewNotificationSys(config *serverConfig, endpoints EndpointList) *Notificat
 }
 
 type eventArgs struct {
-	EventName  event.Name
-	BucketName string
-	Object     ObjectInfo
-	ReqParams  map[string]string
-	Host       string
-	Port       string
-	UserAgent  string
+	EventName    event.Name
+	BucketName   string
+	Object       ObjectInfo
+	ReqParams    map[string]string
+	RespElements map[string]string
+	Host         string
+	Port         string
+	UserAgent    string
 }
 
 // ToEvent - converts to notification event.
@@ -474,6 +475,13 @@ func (args eventArgs) ToEvent() event.Event {
 	eventTime := UTCNow()
 	uniqueID := fmt.Sprintf("%X", eventTime.UnixNano())
 
+	respElements := map[string]string{
+		"x-amz-request-id":        uniqueID,
+		"x-minio-origin-endpoint": getOriginEndpoint(), // Minio specific custom elements.
+	}
+	if args.RespElements["content-length"] != "" {
+		respElements["content-length"] = args.RespElements["content-length"]
+	}
 	newEvent := event.Event{
 		EventVersion:      "2.0",
 		EventSource:       "minio:s3",
@@ -482,10 +490,7 @@ func (args eventArgs) ToEvent() event.Event {
 		EventName:         args.EventName,
 		UserIdentity:      event.Identity{creds.AccessKey},
 		RequestParameters: args.ReqParams,
-		ResponseElements: map[string]string{
-			"x-amz-request-id":        uniqueID,
-			"x-minio-origin-endpoint": getOriginEndpoint(), // Minio specific custom elements.
-		},
+		ResponseElements:  respElements,
 		S3: event.Metadata{
 			SchemaVersion:   "1.0",
 			ConfigurationID: "Config",

cmd/object-handlers.go

@@ -405,13 +405,14 @@ func (api objectAPIHandlers) GetObjectHandler(w http.ResponseWriter, r *http.Req
 
 	// Notify object accessed via a GET request.
 	sendEvent(eventArgs{
-		EventName:  event.ObjectAccessedGet,
-		BucketName: bucket,
-		Object:     objInfo,
-		ReqParams:  extractReqParams(r),
-		UserAgent:  r.UserAgent(),
-		Host:       host,
-		Port:       port,
+		EventName:    event.ObjectAccessedGet,
+		BucketName:   bucket,
+		Object:       objInfo,
+		ReqParams:    extractReqParams(r),
+		RespElements: extractRespElements(w),
+		UserAgent:    r.UserAgent(),
+		Host:         host,
+		Port:         port,
 	})
 }
 
@@ -509,13 +510,14 @@ func (api objectAPIHandlers) HeadObjectHandler(w http.ResponseWriter, r *http.Re
 
 	// Notify object accessed via a HEAD request.
 	sendEvent(eventArgs{
-		EventName:  event.ObjectAccessedHead,
-		BucketName: bucket,
-		Object:     objInfo,
-		ReqParams:  extractReqParams(r),
-		UserAgent:  r.UserAgent(),
-		Host:       host,
-		Port:       port,
+		EventName:    event.ObjectAccessedHead,
+		BucketName:   bucket,
+		Object:       objInfo,
+		ReqParams:    extractReqParams(r),
+		RespElements: extractRespElements(w),
+		UserAgent:    r.UserAgent(),
+		Host:         host,
+		Port:         port,
 	})
 }