forked from micro/micro
-
Notifications
You must be signed in to change notification settings - Fork 1
/
metadata.go
executable file
·154 lines (134 loc) · 3.46 KB
/
metadata.go
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
// 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
//
// https://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.
//
// Original source: github.com/micro/go-micro/v3/metadata/metadata.go
// Package metadata is a way of defining message headers
package metadata
import (
"context"
"strings"
)
type metadataKey struct{}
// Metadata is our way of representing request headers internally.
// They're used at the RPC level and translate back and forth
// from Transport headers.
type Metadata map[string]string
func (md Metadata) Get(key string) (string, bool) {
// attempt to get as is
val, ok := md[key]
if ok {
return val, ok
}
// attempt to get lower case
val, ok = md[strings.Title(key)]
return val, ok
}
func (md Metadata) Set(key, val string) {
md[key] = val
}
func (md Metadata) Delete(key string) {
// delete key as-is
delete(md, key)
// delete also Title key
delete(md, strings.Title(key))
}
// Copy makes a copy of the metadata
func Copy(md Metadata) Metadata {
cmd := make(Metadata, len(md))
for k, v := range md {
cmd[k] = v
}
return cmd
}
func Merge(md Metadata, patchMd Metadata, overwrite bool) Metadata {
cmd := Copy(md)
for k, v := range patchMd {
if _, ok := cmd[k]; ok && !overwrite {
// skip
} else if v != "" {
cmd[k] = v
} else {
delete(cmd, k)
}
}
return cmd
}
// Delete key from metadata
func Delete(ctx context.Context, k string) context.Context {
return Set(ctx, k, "")
}
// Set add key with val to metadata
func Set(ctx context.Context, k, v string) context.Context {
md, ok := FromContext(ctx)
if !ok {
md = make(Metadata)
}
if v == "" {
delete(md, k)
} else {
md[k] = v
}
return context.WithValue(ctx, metadataKey{}, md)
}
// Get returns a single value from metadata in the context
func Get(ctx context.Context, key string) (string, bool) {
md, ok := FromContext(ctx)
if !ok {
return "", ok
}
// attempt to get as is
val, ok := md[key]
if ok {
return val, ok
}
// attempt to get lower case
val, ok = md[strings.Title(key)]
return val, ok
}
// FromContext returns metadata from the given context
func FromContext(ctx context.Context) (Metadata, bool) {
md, ok := ctx.Value(metadataKey{}).(Metadata)
if !ok {
return nil, ok
}
// capitalise all values
newMD := make(Metadata, len(md))
for k, v := range md {
newMD[strings.Title(k)] = v
}
return newMD, ok
}
// NewContext creates a new context with the given metadata
func NewContext(ctx context.Context, md Metadata) context.Context {
return context.WithValue(ctx, metadataKey{}, md)
}
// MergeContext merges metadata to existing metadata, overwriting if specified
func MergeContext(ctx context.Context, patchMd Metadata, overwrite bool) context.Context {
if ctx == nil {
ctx = context.Background()
}
md, _ := ctx.Value(metadataKey{}).(Metadata)
cmd := make(Metadata, len(md))
for k, v := range md {
cmd[k] = v
}
for k, v := range patchMd {
if _, ok := cmd[k]; ok && !overwrite {
// skip
} else if v != "" {
cmd[k] = v
} else {
delete(cmd, k)
}
}
return context.WithValue(ctx, metadataKey{}, cmd)
}