api: DRY code and add new test

This commit makes code cleaner and reduces the repetitions in the code
base. Specifically, it reduces the clutter in setObjectHeaders. It also
merges encodeSuccessResponse and encodeErrorResponse together because
they served no purpose differently. Finally, it adds a simple test for
generateRequestID.

api-headers.go

@@ -50,10 +50,9 @@ func setCommonHeaders(w http.ResponseWriter) {
 	w.Header().Set("Accept-Ranges", "bytes")
 }
 
-// Write error response headers
-func encodeErrorResponse(response interface{}) []byte {
+// Encodes the response headers into XML format.
+func encodeResponse(response interface{}) []byte {
 	var bytesBuffer bytes.Buffer
-	// write common headers
 	bytesBuffer.WriteString(xml.Header)
 	e := xml.NewEncoder(&bytesBuffer)
 	e.Encode(response)
@@ -63,40 +62,26 @@ func encodeErrorResponse(response interface{}) []byte {
 // Write object header
 func setObjectHeaders(w http.ResponseWriter, metadata fs.ObjectMetadata, contentRange *httpRange) {
 	// set common headers
-	if contentRange != nil {
-		if contentRange.length > 0 {
-			w.Header().Set("Content-Length", strconv.FormatInt(contentRange.length, 10))
 	setCommonHeaders(w)
-		} else {
-			w.Header().Set("Content-Length", strconv.FormatInt(metadata.Size, 10))
-			setCommonHeaders(w)
-		}
-	} else {
-		w.Header().Set("Content-Length", strconv.FormatInt(metadata.Size, 10))
-		setCommonHeaders(w)
-	}
-	// set object headers
+
+	// set object-related metadata headers
 	lastModified := metadata.LastModified.UTC().Format(http.TimeFormat)
-	// object related headers
+	w.Header().Set("Last-Modified", lastModified)
+
 	w.Header().Set("Content-Type", metadata.ContentType)
 	if metadata.MD5 != "" {
 		w.Header().Set("ETag", "\""+metadata.MD5+"\"")
 	}
-	w.Header().Set("Last-Modified", lastModified)
 
-	// set content range
+	w.Header().Set("Content-Length", strconv.FormatInt(metadata.Size, 10))
+
+	// for providing ranged content
 	if contentRange != nil {
 		if contentRange.start > 0 || contentRange.length > 0 {
+			// override content-length
+			w.Header().Set("Content-Length", strconv.FormatInt(contentRange.length, 10))
 			w.Header().Set("Content-Range", contentRange.String())
 			w.WriteHeader(http.StatusPartialContent)
 		}
 	}
 }
-
-func encodeSuccessResponse(response interface{}) []byte {
-	var bytesBuffer bytes.Buffer
-	bytesBuffer.WriteString(xml.Header)
-	e := xml.NewEncoder(&bytesBuffer)
-	e.Encode(response)
-	return bytesBuffer.Bytes()
-}

api-headers_test.go

@@ -0,0 +1,40 @@
+/*
+ * Minio Cloud Storage, (C) 2015, 2016 Minio, Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package main
+
+import (
+	"testing"
+)
+
+func TestGenerateRequestID(t *testing.T) {
+	// Ensure that it returns an alphanumeric result of length 16.
+	var id []byte = generateRequestID()
+
+	if len(id) != 16 {
+		t.Fail()
+	}
+
+	var e rune
+	for _, char := range id {
+		e = rune(char)
+
+		// Ensure that it is alphanumeric, in this case, between 0-9 and A-Z.
+		if !(('0' <= e && e <= '9') || ('A' <= e && e <= 'Z')) {
+			t.Fail()
+		}
+	}
+}

api-response.go

@@ -436,7 +436,7 @@ func writeErrorResponse(w http.ResponseWriter, req *http.Request, errorType int,
 	error := getErrorCode(errorType)
 	// generate error response
 	errorResponse := getErrorResponse(error, resource)
-	encodedErrorResponse := encodeErrorResponse(errorResponse)
+	encodedErrorResponse := encodeResponse(errorResponse)
 	// set common headers
 	setCommonHeaders(w)
 	// write Header

bucket-handlers.go

@@ -63,9 +63,9 @@ func (api storageAPI) GetBucketLocationHandler(w http.ResponseWriter, r *http.Re
 	}
 
 	// Generate response.
-	encodedSuccessResponse := encodeSuccessResponse(LocationResponse{})
+	encodedSuccessResponse := encodeResponse(LocationResponse{})
 	if api.Region != "us-east-1" {
-		encodedSuccessResponse = encodeSuccessResponse(LocationResponse{
+		encodedSuccessResponse = encodeResponse(LocationResponse{
 			Location: api.Region,
 		})
 	}
@@ -117,7 +117,7 @@ func (api storageAPI) ListMultipartUploadsHandler(w http.ResponseWriter, r *http
 	}
 	// generate response
 	response := generateListMultipartUploadsResponse(bucket, resources)
-	encodedSuccessResponse := encodeSuccessResponse(response)
+	encodedSuccessResponse := encodeResponse(response)
 	// write headers.
 	setCommonHeaders(w)
 	// write success response.
@@ -160,7 +160,7 @@ func (api storageAPI) ListObjectsHandler(w http.ResponseWriter, r *http.Request)
 	if err == nil {
 		// generate response
 		response := generateListObjectsResponse(bucket, prefix, marker, delimiter, maxkeys, listResp)
-		encodedSuccessResponse := encodeSuccessResponse(response)
+		encodedSuccessResponse := encodeResponse(response)
 		// Write headers
 		setCommonHeaders(w)
 		// Write success response.
@@ -201,7 +201,7 @@ func (api storageAPI) ListBucketsHandler(w http.ResponseWriter, r *http.Request)
 	if err == nil {
 		// generate response
 		response := generateListBucketsResponse(buckets)
-		encodedSuccessResponse := encodeSuccessResponse(response)
+		encodedSuccessResponse := encodeResponse(response)
 		// write headers
 		setCommonHeaders(w)
 		// write response
@@ -475,7 +475,7 @@ func (api storageAPI) GetBucketACLHandler(w http.ResponseWriter, r *http.Request
 	}
 	// Generate response
 	response := generateAccessControlPolicyResponse(bucketMetadata.ACL)
-	encodedSuccessResponse := encodeSuccessResponse(response)
+	encodedSuccessResponse := encodeResponse(response)
 	// Write headers
 	setCommonHeaders(w)
 	// Write success response.

object-handlers.go

@@ -392,7 +392,7 @@ func (api storageAPI) CopyObjectHandler(w http.ResponseWriter, r *http.Request)
 		return
 	}
 	response := generateCopyObjectResponse(metadata.MD5, metadata.LastModified)
-	encodedSuccessResponse := encodeSuccessResponse(response)
+	encodedSuccessResponse := encodeResponse(response)
 	// write headers
 	setCommonHeaders(w)
 	// write success response.
@@ -534,7 +534,7 @@ func (api storageAPI) NewMultipartUploadHandler(w http.ResponseWriter, r *http.R
 	}
 
 	response := generateInitiateMultipartUploadResponse(bucket, object, uploadID)
-	encodedSuccessResponse := encodeSuccessResponse(response)
+	encodedSuccessResponse := encodeResponse(response)
 	// write headers
 	setCommonHeaders(w)
 	// write success response.
@@ -723,7 +723,7 @@ func (api storageAPI) ListObjectPartsHandler(w http.ResponseWriter, r *http.Requ
 		return
 	}
 	response := generateListPartsResponse(objectResourcesMetadata)
-	encodedSuccessResponse := encodeSuccessResponse(response)
+	encodedSuccessResponse := encodeResponse(response)
 	// write headers.
 	setCommonHeaders(w)
 	// write success response.
@@ -802,7 +802,7 @@ func (api storageAPI) CompleteMultipartUploadHandler(w http.ResponseWriter, r *h
 	location := getLocation(r)
 	// Generate complete multipart response.
 	response := generateCompleteMultpartUploadResponse(bucket, object, location, metadata.MD5)
-	encodedSuccessResponse := encodeSuccessResponse(response)
+	encodedSuccessResponse := encodeResponse(response)
 	// write headers
 	setCommonHeaders(w)
 	// write success response.