tryCompute{ContentLength, Etag}: add special cases for strings.Reader, nil

2 files changed, 31 insertions, 10 deletions

diff --git a/object.go b/object.go
index fb72aeb..8ef314a 100644
--- a/object.go
+++ b/object.go
@@ -203,33 +203,47 @@ func (o *Object) Upload(content io.Reader, opts *RequestOptions) error {
 	return nil
 }
 
-//TODO add support for strings.Reader below
+type readerWithLen interface {
+	//Returns the number of bytes in the unread portion of the buffer.
+	//Implemented by bytes.Reader, bytes.Buffer and strings.Reader.
+	Len() int
+}
 
 func tryComputeContentLength(content io.Reader, headers ObjectHeaders) {
 	h := headers.SizeBytes()
 	if h.Exists() {
 		return
 	}
-	switch r := content.(type) {
-	case *bytes.Buffer:
-		h.Set(uint64(r.Len()))
-	case *bytes.Reader:
+
+	if content == nil {
+		h.Set(0)
+	} else if r, ok := content.(readerWithLen); ok {
 		h.Set(uint64(r.Len()))
 	}
 }
 
+//This covers both bytes.Reader and strings.Reader in a way that is compatible
+//with earlier versions of Go that don't have strings.Reader yet.
+type likeBytesReader interface {
+	io.WriterTo
+	io.Seeker
+}
+
 func tryComputeEtag(content io.Reader, headers ObjectHeaders) {
 	h := headers.Etag()
 	if h.Exists() {
 		return
 	}
 	switch r := content.(type) {
+	case nil:
+		sum := md5.Sum(nil)
+		h.Set(hex.EncodeToString(sum[:]))
 	case *bytes.Buffer:
 		//bytes.Buffer has a method that returns the unread portion of the buffer,
 		//so this one is easy
 		sum := md5.Sum(r.Bytes())
 		h.Set(hex.EncodeToString(sum[:]))
-	case *bytes.Reader:
+	case likeBytesReader:
 		//bytes.Reader does not have such a method, but it is an io.Seeker, so we
 		//can read the entire thing and then seek back to where we started
 		hash := md5.New()
diff --git a/tests/object_test.go b/tests/object_test.go
index b42294a..1bbf953 100644
--- a/tests/object_test.go
+++ b/tests/object_test.go
@@ -23,6 +23,7 @@ import (
 	"io"
 	"io/ioutil"
 	"net/http"
+	"strings"
 	"testing"
 
 	"github.com/majewsky/schwift"
@@ -75,14 +76,20 @@ func TestObjectUpload(t *testing.T) {
 		expectSuccess(t, err)
 		expectObjectContent(t, obj, objectExampleContent)
 
-		//test upload with opaque io.Reader
+		//test upload with strings.Reader
 		obj = c.Object("upload3")
+		err = obj.Upload(strings.NewReader(string(objectExampleContent)), nil)
+		expectSuccess(t, err)
+		expectObjectContent(t, obj, objectExampleContent)
+
+		//test upload with opaque io.Reader
+		obj = c.Object("upload4")
 		err = obj.Upload(opaqueReader{bytes.NewReader(objectExampleContent)}, nil)
 		expectSuccess(t, err)
 		expectObjectContent(t, obj, objectExampleContent)
 
 		//test upload with io.Writer
-		obj = c.Object("upload4")
+		obj = c.Object("upload5")
 		err = obj.UploadWithWriter(nil, func(w io.Writer) error {
 			_, err := w.Write(objectExampleContent)
 			return err
@@ -91,13 +98,13 @@ func TestObjectUpload(t *testing.T) {
 		expectObjectContent(t, obj, objectExampleContent)
 
 		//test upload with empty reader (should create zero-byte-sized object)
-		obj = c.Object("upload5")
+		obj = c.Object("upload6")
 		err = obj.Upload(eofReader{}, nil)
 		expectSuccess(t, err)
 		expectObjectContent(t, obj, nil)
 
 		//test upload without reader (should create zero-byte-sized object)
-		obj = c.Object("upload6")
+		obj = c.Object("upload7")
 		err = obj.Upload(nil, nil)
 		expectSuccess(t, err)
 		expectObjectContent(t, obj, nil)