145 строки
4.0 KiB
Go
145 строки
4.0 KiB
Go
/*
|
|
*
|
|
* Copyright 2014, Google Inc.
|
|
* All rights reserved.
|
|
*
|
|
* Redistribution and use in source and binary forms, with or without
|
|
* modification, are permitted provided that the following conditions are
|
|
* met:
|
|
*
|
|
* * Redistributions of source code must retain the above copyright
|
|
* notice, this list of conditions and the following disclaimer.
|
|
* * Redistributions in binary form must reproduce the above
|
|
* copyright notice, this list of conditions and the following disclaimer
|
|
* in the documentation and/or other materials provided with the
|
|
* distribution.
|
|
* * Neither the name of Google Inc. nor the names of its
|
|
* contributors may be used to endorse or promote products derived from
|
|
* this software without specific prior written permission.
|
|
*
|
|
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
|
|
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
|
|
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
|
|
* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
|
|
* OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
|
|
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
|
|
* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
|
|
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
|
|
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
|
|
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
|
|
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
|
|
*
|
|
*/
|
|
|
|
// Package metadata define the structure of the metadata supported by gRPC library.
|
|
package metadata // import "google.golang.org/grpc/metadata"
|
|
|
|
import (
|
|
"encoding/base64"
|
|
"fmt"
|
|
"strings"
|
|
|
|
"golang.org/x/net/context"
|
|
)
|
|
|
|
const (
|
|
binHdrSuffix = "-bin"
|
|
)
|
|
|
|
// grpc-http2 requires ASCII header key and value (more detail can be found in
|
|
// "Requests" subsection in go/grpc-http2).
|
|
func isASCII(s string) bool {
|
|
for _, c := range s {
|
|
if c > 127 {
|
|
return false
|
|
}
|
|
}
|
|
return true
|
|
}
|
|
|
|
// encodeKeyValue encodes key and value qualified for transmission via gRPC.
|
|
// Transmitting binary headers violates HTTP/2 spec.
|
|
// TODO(zhaoq): Maybe check if k is ASCII also.
|
|
func encodeKeyValue(k, v string) (string, string) {
|
|
if isASCII(v) {
|
|
return k, v
|
|
}
|
|
key := k + binHdrSuffix
|
|
val := base64.StdEncoding.EncodeToString([]byte(v))
|
|
return key, string(val)
|
|
}
|
|
|
|
// DecodeKeyValue returns the original key and value corresponding to the
|
|
// encoded data in k, v.
|
|
func DecodeKeyValue(k, v string) (string, string, error) {
|
|
if !strings.HasSuffix(k, binHdrSuffix) {
|
|
return k, v, nil
|
|
}
|
|
key := k[:len(k)-len(binHdrSuffix)]
|
|
val, err := base64.StdEncoding.DecodeString(v)
|
|
if err != nil {
|
|
return "", "", err
|
|
}
|
|
return key, string(val), nil
|
|
}
|
|
|
|
// MD is a mapping from metadata keys to values. Users should use the following
|
|
// two convenience functions New and Pairs to generate MD.
|
|
type MD map[string]string
|
|
|
|
// New creates a MD from given key-value map.
|
|
func New(m map[string]string) MD {
|
|
md := MD{}
|
|
for k, v := range m {
|
|
key, val := encodeKeyValue(k, v)
|
|
md[key] = val
|
|
}
|
|
return md
|
|
}
|
|
|
|
// Pairs returns an MD formed by the mapping of key, value ...
|
|
// Pairs panics if len(kv) is odd.
|
|
func Pairs(kv ...string) MD {
|
|
if len(kv)%2 == 1 {
|
|
panic(fmt.Sprintf("metadata: Pairs got the odd number of input pairs for metadata: %d", len(kv)))
|
|
}
|
|
md := MD{}
|
|
var k string
|
|
for i, s := range kv {
|
|
if i%2 == 0 {
|
|
k = s
|
|
continue
|
|
}
|
|
key, val := encodeKeyValue(k, s)
|
|
md[key] = val
|
|
}
|
|
return md
|
|
}
|
|
|
|
// Len returns the number of items in md.
|
|
func (md MD) Len() int {
|
|
return len(md)
|
|
}
|
|
|
|
// Copy returns a copy of md.
|
|
func (md MD) Copy() MD {
|
|
out := MD{}
|
|
for k, v := range md {
|
|
out[k] = v
|
|
}
|
|
return out
|
|
}
|
|
|
|
type mdKey struct{}
|
|
|
|
// NewContext creates a new context with md attached.
|
|
func NewContext(ctx context.Context, md MD) context.Context {
|
|
return context.WithValue(ctx, mdKey{}, md)
|
|
}
|
|
|
|
// FromContext returns the MD in ctx if it exists.
|
|
func FromContext(ctx context.Context) (md MD, ok bool) {
|
|
md, ok = ctx.Value(mdKey{}).(MD)
|
|
return
|
|
}
|