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/******************************************************************************
*
* 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
}
//Clear sets the value to this key to the empty string, such that a Post() with
//this Metadata will remove the existing value from this metadata key on the server.
func (m Metadata) Clear(key string) {
m.Set(key, "")
}
//Del works just like http.Header.Del().
//
//Del deletes a key from the Metadata instance. When the Metadata instance
//is then sent to the server with Post(), Del() has different effects depending
//on context because of Swift's inconsistent API:
//
//For account or container metadata, a key which has been deleted with Del() will
//remain unchanged on the server. To remove the key on the server, use Clear()
//instead.
//
//For object metadata, deleting a key will cause that key to be deleted on the
//server. Del() is identical to Clear() in this case.
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
}
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