HEAD request should have Content-Length for only successful response, there is no response body for errors, just header is sufficient - fixes #603

http://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html#sec14.13

"""  in the case of the HEAD method, the size of the entity-body that would have been sent had the request been a GET. """

pkg/api/api_bucket_handlers.go

@@ -285,11 +285,31 @@ func (server *minioAPI) putBucketACLHandler(w http.ResponseWriter, req *http.Req
 // return responses such as 404 Not Found and 403 Forbidden.
 func (server *minioAPI) headBucketHandler(w http.ResponseWriter, req *http.Request) {
 	acceptsContentType := getContentType(req)
-	// verify if bucket allows this operation
-	if !server.isValidOp(w, req, acceptsContentType) {
-		return
-	}
 
-	// Always a success if isValidOp succeeds
+	vars := mux.Vars(req)
+	bucket := vars["bucket"]
+
+	_, err := server.driver.GetBucketMetadata(bucket)
+	switch iodine.ToError(err).(type) {
+	case nil:
+		{
 			writeSuccessResponse(w, acceptsContentType)
+		}
+	case drivers.BucketNotFound:
+		{
+			error := getErrorCode(NoSuchBucket)
+			w.WriteHeader(error.HTTPStatusCode)
+		}
+	case drivers.BucketNameInvalid:
+		{
+			error := getErrorCode(InvalidBucketName)
+			w.WriteHeader(error.HTTPStatusCode)
+		}
+	default:
+		{
+			log.Println(err)
+			error := getErrorCode(InternalError)
+			w.WriteHeader(error.HTTPStatusCode)
+		}
+	}
 }

pkg/api/api_object_handlers.go

@@ -115,16 +115,22 @@ func (server *minioAPI) headObjectHandler(w http.ResponseWriter, req *http.Reque
 		}
 	case drivers.ObjectNotFound:
 		{
-			writeErrorResponse(w, req, NoSuchKey, acceptsContentType, req.URL.Path)
+			error := getErrorCode(NoSuchKey)
+			w.Header().Set("Server", "Minio")
+			w.WriteHeader(error.HTTPStatusCode)
 		}
 	case drivers.ObjectNameInvalid:
 		{
-			writeErrorResponse(w, req, NoSuchKey, acceptsContentType, req.URL.Path)
+			error := getErrorCode(NoSuchKey)
+			w.Header().Set("Server", "Minio")
+			w.WriteHeader(error.HTTPStatusCode)
 		}
 	default:
 		{
 			log.Error.Println(iodine.New(err, nil))
-			writeErrorResponse(w, req, InternalError, acceptsContentType, req.URL.Path)
+			error := getErrorCode(InternalError)
+			w.Header().Set("Server", "Minio")
+			w.WriteHeader(error.HTTPStatusCode)
 		}
 	}
 }
@@ -227,18 +233,24 @@ func (server *minioAPI) newMultipartUploadHandler(w http.ResponseWriter, req *ht
 	uploadID, err := server.driver.NewMultipartUpload(bucket, object, "")
 	switch err := iodine.ToError(err).(type) {
 	case nil:
+		{
 			response := generateInitiateMultipartUploadResult(bucket, object, uploadID)
 			encodedSuccessResponse := encodeSuccessResponse(response, acceptsContentType)
 			// write headers
 			setCommonHeaders(w, getContentTypeString(acceptsContentType), len(encodedSuccessResponse))
 			// write body
 			w.Write(encodedSuccessResponse)
+		}
 	case drivers.ObjectExists:
+		{
 			writeErrorResponse(w, req, MethodNotAllowed, acceptsContentType, req.URL.Path)
+		}
 	default:
+		{
 			log.Println(iodine.New(err, nil))
 			writeErrorResponse(w, req, InternalError, acceptsContentType, req.URL.Path)
 		}
+	}
 }
 
 func (server *minioAPI) putObjectPartHandler(w http.ResponseWriter, req *http.Request) {
@@ -346,14 +358,20 @@ func (server *minioAPI) abortMultipartUploadHandler(w http.ResponseWriter, req *
 	err := server.driver.AbortMultipartUpload(bucket, object, objectResourcesMetadata.UploadID)
 	switch err := iodine.ToError(err).(type) {
 	case nil:
+		{
 			setCommonHeaders(w, getContentTypeString(acceptsContentType), 0)
 			w.WriteHeader(http.StatusNoContent)
+		}
 	case drivers.InvalidUploadID:
+		{
 			writeErrorResponse(w, req, NoSuchUpload, acceptsContentType, req.URL.Path)
+		}
 	default:
+		{
 			log.Println(err)
 			writeErrorResponse(w, req, InternalError, acceptsContentType, req.URL.Path)
 		}
+	}
 }
 
 func (server *minioAPI) listObjectPartsHandler(w http.ResponseWriter, req *http.Request) {
@@ -375,18 +393,24 @@ func (server *minioAPI) listObjectPartsHandler(w http.ResponseWriter, req *http.
 	objectResourcesMetadata, err := server.driver.ListObjectParts(bucket, object, objectResourcesMetadata)
 	switch err := iodine.ToError(err).(type) {
 	case nil:
+		{
 			response := generateListPartsResult(objectResourcesMetadata)
 			encodedSuccessResponse := encodeSuccessResponse(response, acceptsContentType)
 			// write headers
 			setCommonHeaders(w, getContentTypeString(acceptsContentType), len(encodedSuccessResponse))
 			// write body
 			w.Write(encodedSuccessResponse)
+		}
 	case drivers.InvalidUploadID:
+		{
 			writeErrorResponse(w, req, NoSuchUpload, acceptsContentType, req.URL.Path)
+		}
 	default:
+		{
 			log.Println(err)
 			writeErrorResponse(w, req, InternalError, acceptsContentType, req.URL.Path)
 		}
+	}
 }
 
 func (server *minioAPI) completeMultipartUploadHandler(w http.ResponseWriter, req *http.Request) {
@@ -422,16 +446,22 @@ func (server *minioAPI) completeMultipartUploadHandler(w http.ResponseWriter, re
 	etag, err := server.driver.CompleteMultipartUpload(bucket, object, objectResourcesMetadata.UploadID, partMap)
 	switch err := iodine.ToError(err).(type) {
 	case nil:
+		{
 			response := generateCompleteMultpartUploadResult(bucket, object, "", etag)
 			encodedSuccessResponse := encodeSuccessResponse(response, acceptsContentType)
 			// write headers
 			setCommonHeaders(w, getContentTypeString(acceptsContentType), len(encodedSuccessResponse))
 			// write body
 			w.Write(encodedSuccessResponse)
+		}
 	case drivers.InvalidUploadID:
+		{
 			writeErrorResponse(w, req, NoSuchUpload, acceptsContentType, req.URL.Path)
+		}
 	default:
+		{
 			log.Println(iodine.New(err, nil))
 			writeErrorResponse(w, req, InternalError, acceptsContentType, req.URL.Path)
 		}
+	}
 }