Add x-amz-expiration header in some S3 responses (#9667)

x-amz-expiration is described in the S3 specification as a header which
indicates if the object in question will expire any time in the future.

cmd/object-handlers.go

@@ -427,6 +427,7 @@ func (api objectAPIHandlers) GetObjectHandler(w http.ResponseWriter, r *http.Req
 	}
 
 	setHeadGetRespHeaders(w, r.URL.Query())
+	setAmzExpirationHeader(w, bucket, objInfo)
 
 	statusCodeWritten := false
 	httpWriter := ioutil.WriteOnClose(w)
@@ -606,6 +607,9 @@ func (api objectAPIHandlers) HeadObjectHandler(w http.ResponseWriter, r *http.Re
 	// Set any additional requested response headers.
 	setHeadGetRespHeaders(w, r.URL.Query())
 
+	// Set the expiration header
+	setAmzExpirationHeader(w, bucket, objInfo)
+
 	// Successful response.
 	if rs != nil {
 		w.WriteHeader(http.StatusPartialContent)
@@ -1165,6 +1169,8 @@ func (api objectAPIHandlers) CopyObjectHandler(w http.ResponseWriter, r *http.Re
 		}
 	}
 
+	setAmzExpirationHeader(w, dstBucket, objInfo)
+
 	response := generateCopyObjectResponse(getDecryptedETag(r.Header, objInfo, false), objInfo.ModTime)
 	encodedSuccessResponse := encodeResponse(response)
 
@@ -1476,10 +1482,14 @@ func (api objectAPIHandlers) PutObjectHandler(w http.ResponseWriter, r *http.Req
 			}
 		}
 	}
+
 	// We must not use the http.Header().Set method here because some (broken)
 	// clients expect the ETag header key to be literally "ETag" - not "Etag" (case-sensitive).
 	// Therefore, we have to set the ETag directly as map entry.
 	w.Header()[xhttp.ETag] = []string{`"` + etag + `"`}
+
+	setAmzExpirationHeader(w, bucket, objInfo)
+
 	writeSuccessResponseHeadersOnly(w)
 
 	// Notify object created event.
@@ -2526,6 +2536,8 @@ func (api objectAPIHandlers) CompleteMultipartUploadHandler(w http.ResponseWrite
 	// Set etag.
 	w.Header()[xhttp.ETag] = []string{"\"" + objInfo.ETag + "\""}
 
+	setAmzExpirationHeader(w, bucket, objInfo)
+
 	// Write success response.
 	writeSuccessResponseXML(w, encodedSuccessResponse)