Update documentation and tests on updating Content-Type

swift.go

@@ -2105,10 +2105,10 @@ func (c *Connection) objectBase(container string, objectName string) (info Objec
 // X-Delete-At or X-Delete-After for expiring objects.
 //
 // You cannot use this to change any of the object's other headers
-// such as Content-Type, ETag, etc.
+// such as ETag, etc.
 //
 // Refer to copying an object when you need to update metadata or
-// other headers such as Content-Type or CORS headers.
+// other headers such as CORS headers.
 //
 // May return ObjectNotFound.
 func (c *Connection) ObjectUpdate(container string, objectName string, h Headers) error {
@@ -2175,11 +2175,12 @@ func (c *Connection) ObjectMove(srcContainer string, srcObjectName string, dstCo
 	return c.ObjectDelete(srcContainer, srcObjectName)
 }
 
-// ObjectUpdateContentType updates the content type of an object
+// ObjectUpdateContentType updates the content type of an object while
+// keeping current custom metadata.
 //
-// This is a convenience method which calls ObjectCopy
-//
-// All other metadata is preserved.
+// This is a convenience method which calls ObjectCopy, which causes data movement.
+// Content-Type can also be updated with ObjectUpdate which updates metadata
+// in place, without need of data movement in the cluster.
 func (c *Connection) ObjectUpdateContentType(container string, objectName string, contentType string) (err error) {
 	h := Headers{"Content-Type": contentType}
 	_, err = c.ObjectCopy(container, objectName, container, objectName, h)

swift_test.go

@@ -41,6 +41,7 @@ var (
 	srv              *swifttest.SwiftServer
 	m1               = swift.Metadata{"Hello": "1", "potato-Salad": "2"}
 	m2               = swift.Metadata{"hello": "", "potato-salad": ""}
+	m3               = swift.Metadata{"sweet-potato-salad": "1"}
 	skipVersionTests = false
 )
 
@@ -1304,6 +1305,29 @@ func TestObjectUpdate2(t *testing.T) {
 	compareMaps(t, headers.ObjectMetadata(), map[string]string{"hello": "", "potato-salad": ""})
 }
 
+func TestObjectUpdate3(t *testing.T) {
+	c, rollback := makeConnectionWithObjectHeaders(t)
+	defer rollback()
+
+	// sanity
+	_, headers, err := c.Object(CONTAINER, OBJECT)
+	if err != nil {
+		t.Fatal(err)
+	}
+	compareMaps(t, headers.ObjectMetadata(), map[string]string{"hello": "1", "potato-salad": "1"})
+
+	// update with new headers
+	err = c.ObjectUpdate(CONTAINER, OBJECT, m3.ObjectHeaders())
+	if err != nil {
+		t.Fatal(err)
+	}
+	_, headers, err = c.Object(CONTAINER, OBJECT)
+	if err != nil {
+		t.Fatal(err)
+	}
+	compareMaps(t, headers.ObjectMetadata(), map[string]string{"sweet-potato-salad": "1"})
+}
+
 func TestContainers(t *testing.T) {
 	c, rollback := makeConnectionWithObjectHeaders(t)
 	defer rollback()
@@ -1612,10 +1636,14 @@ func TestObjectMove(t *testing.T) {
 func TestObjectUpdateContentType(t *testing.T) {
 	c, rollback := makeConnectionWithObjectHeaders(t)
 	defer rollback()
+
+	// to maintain backwards-compatibility update content-type with
+	// ObjectUpdateContentType, which copies object in place
 	err := c.ObjectUpdateContentType(CONTAINER, OBJECT, "text/potato")
 	if err != nil {
 		t.Fatal(err)
 	}
+
 	// Re-read the metadata to see if it is correct
 	_, headers, err := c.Object(CONTAINER, OBJECT)
 	if err != nil {
@@ -1624,7 +1652,27 @@ func TestObjectUpdateContentType(t *testing.T) {
 	if headers["Content-Type"] != "text/potato" {
 		t.Error("Didn't change content type")
 	}
+
+	// ObjectUpdateContentType keeps old metadata because copy was used
 	compareMaps(t, headers.ObjectMetadata(), map[string]string{"hello": "1", "potato-salad": "2"})
+
+	// Now update content-type with ObjectUpdate
+	// Note, old metadata is lost if not sent again
+	h := swift.Headers{"Content-Type": "text/sweet-potato", "X-Object-Meta-Sweet-Potato-Salad": "1"}
+	err = c.ObjectUpdate(CONTAINER, OBJECT, h)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	// Re-read the metadata to see if it is correct
+	_, headers, err = c.Object(CONTAINER, OBJECT)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if headers["Content-Type"] != "text/sweet-potato" {
+		t.Error("Didn't change content type")
+	}
+	compareMaps(t, headers.ObjectMetadata(), map[string]string{"sweet-potato-salad": "1"})
 }
 
 func TestVersionContainerCreate(t *testing.T) {