use dedicated Metadata type instead of http.Header

3 files changed, 87 insertions, 22 deletions

diff --git a/account_test.go b/account_test.go
index 7a07fa4..da49a8c 100644
--- a/account_test.go
+++ b/account_test.go
@@ -19,7 +19,6 @@
 package schwift
 
 import (
-	"net/http"
 	"testing"
 )
 
@@ -40,7 +39,7 @@ func TestAccountBasic(t *testing.T) {
 func TestAccountMetadata(t *testing.T) {
 	testWithAccount(t, func(a *Account) {
 		err := a.Post(AccountHeaders{
-			Metadata: http.Header{"Schwift-Test": {"first"}},
+			Metadata: NewMetadata("schwift-test", "first"),
 		}, nil)
 		if !expectError(t, err, nil) {
 			t.FailNow()
diff --git a/headers.go b/headers.go
index c2acc9b..eb65488 100644
--- a/headers.go
+++ b/headers.go
@@ -33,10 +33,10 @@ import (
 //headers, as noted in the tags next to each field. Well-known metadata headers
 //can be accessed in a type-safe way using the methods on this type.
 type AccountHeaders struct {
-	BytesUsed      uint64      `schwift:"ro,X-Account-Bytes-Used"`
-	ContainerCount uint64      `schwift:"ro,X-Account-Container-Count"`
-	ObjectCount    uint64      `schwift:"ro,X-Account-Object-Count"`
-	Metadata       http.Header `schwift:"rw,X-Account-Meta-"`
+	BytesUsed      uint64   `schwift:"ro,X-Account-Bytes-Used"`
+	ContainerCount uint64   `schwift:"ro,X-Account-Container-Count"`
+	ObjectCount    uint64   `schwift:"ro,X-Account-Object-Count"`
+	Metadata       Metadata `schwift:"rw,X-Account-Meta-"`
 	Raw            http.Header
 }
 
@@ -76,7 +76,7 @@ func (a AccountHeaders) TempURLKey2() StringField {
 //    headers.TempURLKey().Set(value + " changed")
 //    headers.TempURLKey().Clear()
 type StringField struct {
-	metadata http.Header
+	metadata Metadata
 	prefix   string
 	key      string
 }
@@ -110,7 +110,7 @@ func (f StringField) Clear() {
 //    ....
 //    headers.QuotaBytes().Clear()
 type UnsignedIntField struct {
-	metadata http.Header
+	metadata Metadata
 	prefix   string
 	key      string
 }
@@ -171,17 +171,17 @@ func parseHeaders(hdr http.Header, target interface{}) error {
 				return MalformedHeaderError{info.HeaderName, err}
 			}
 			*fieldPtr = value
-		case *http.Header:
+		case *Metadata:
 			//collect all headers with a prefix equal to `headerName`
-			result := make(http.Header)
-			for key, values := range hdr {
+			values := make(Metadata)
+			for key, value := range hdr {
 				key = textproto.CanonicalMIMEHeaderKey(key)
-				if len(values) > 0 && strings.HasPrefix(key, info.HeaderName) {
+				if strings.HasPrefix(key, info.HeaderName) {
 					key = strings.TrimPrefix(key, info.HeaderName)
-					result[key] = values
+					values[key] = value[0]
 				}
 			}
-			*fieldPtr = result
+			*fieldPtr = values
 		default:
 			panic(fmt.Sprintf("parseHeaders: cannot handle field type %T", fieldPtr))
 		}
@@ -205,14 +205,8 @@ func compileHeaders(headers interface{}, opts *RequestOptions) RequestOptions {
 			hdr.Set(info.HeaderName, *fieldPtr)
 		case *uint64:
 			hdr.Set(info.HeaderName, strconv.FormatUint(*fieldPtr, 10))
-		case *http.Header:
-			for key, values := range *fieldPtr {
-				//Swift only supports one value per metadata field
-				value := ""
-				if len(values) > 0 {
-					value = values[0]
-				}
-
+		case *Metadata:
+			for key, value := range *fieldPtr {
 				//empty string means that this key shall be removed
 				if value == "" {
 					//for object metadata, a key is removed by just omitting it...
diff --git a/metadata.go b/metadata.go
new file mode 100644
index 0000000..3e01c02
--- /dev/null
+++ b/metadata.go
@@ -0,0 +1,72 @@
+/******************************************************************************
+*
+*  Copyright 2018 Stefan Majewsky <majewsky@gmx.net>
+*
+*  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 schwift
+
+import "net/textproto"
+
+//Metadata works like http.Header, but does not allow multiple values per key.
+type Metadata map[string]string
+
+//NewMetadata constructs a Metadata instance from a list of key-value pairs
+//with compact syntax. It is recommended over a map literal since it correctly
+//formats keys with textproto.CanonicalMIMEHeaderKey(). For example:
+//
+//    m = NewMetadata(
+//        "color", "blue",
+//        "size", "large",
+//    )
+//
+//    //...is equivalent to...
+//
+//    m = make(Metadata)
+//    m.Set("color", "blue")
+//    m.Set("size", "large")
+//
+//NewMetadata panics if it is called with an odd number of arguments.
+func NewMetadata(args ...string) Metadata {
+	if len(args)%2 == 1 {
+		panic("NewMetadata called with an odd number of arguments")
+	}
+	m := make(Metadata)
+	for idx := 0; idx < len(args); idx += 2 {
+		m.Set(args[idx], args[idx+1])
+	}
+	return m
+}
+
+//Del works just like http.Header.Del().
+func (m Metadata) Del(key string) {
+	k := textproto.CanonicalMIMEHeaderKey(key)
+	delete(m, k)
+}
+
+//Get works just like http.Header.Get().
+func (m Metadata) Get(key string) string {
+	if m == nil {
+		return ""
+	}
+	k := textproto.CanonicalMIMEHeaderKey(key)
+	return m[k]
+}
+
+//Set works just like http.Header.Set().
+func (m Metadata) Set(key, value string) {
+	k := textproto.CanonicalMIMEHeaderKey(key)
+	m[k] = value
+}