-
Notifications
You must be signed in to change notification settings - Fork 0
/
entity_accessors.go
executable file
·162 lines (143 loc) · 5.05 KB
/
entity_accessors.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
155
156
157
158
159
160
161
162
package restful
// Copyright 2015 Ernest Micklei. All rights reserved.
// Use of this source code is governed by a license
// that can be found in the LICENSE file.
import (
"encoding/xml"
"strings"
"sync"
)
// EntityReaderWriter can read and write values using an encoding such as JSON,XML.
type EntityReaderWriter interface {
// Read a serialized version of the value from the request.
// The Request may have a decompressing reader. Depends on Content-Encoding.
Read(req *Request, v interface{}) error
// Write a serialized version of the value on the response.
// The Response may have a compressing writer. Depends on Accept-Encoding.
// status should be a valid Http Status code
Write(resp *Response, status int, v interface{}) error
}
// entityAccessRegistry is a singleton
var entityAccessRegistry = &entityReaderWriters{
protection: new(sync.RWMutex),
accessors: map[string]EntityReaderWriter{},
}
// entityReaderWriters associates MIME to an EntityReaderWriter
type entityReaderWriters struct {
protection *sync.RWMutex
accessors map[string]EntityReaderWriter
}
func init() {
RegisterEntityAccessor(MIME_JSON, NewEntityAccessorJSON(MIME_JSON))
RegisterEntityAccessor(MIME_XML, NewEntityAccessorXML(MIME_XML))
}
// RegisterEntityAccessor add/overrides the ReaderWriter for encoding content with this MIME type.
func RegisterEntityAccessor(mime string, erw EntityReaderWriter) {
entityAccessRegistry.protection.Lock()
defer entityAccessRegistry.protection.Unlock()
entityAccessRegistry.accessors[mime] = erw
}
// NewEntityAccessorJSON returns a new EntityReaderWriter for accessing JSON content.
// This package is already initialized with such an accessor using the MIME_JSON contentType.
func NewEntityAccessorJSON(contentType string) EntityReaderWriter {
return entityJSONAccess{ContentType: contentType}
}
// NewEntityAccessorXML returns a new EntityReaderWriter for accessing XML content.
// This package is already initialized with such an accessor using the MIME_XML contentType.
func NewEntityAccessorXML(contentType string) EntityReaderWriter {
return entityXMLAccess{ContentType: contentType}
}
// accessorAt returns the registered ReaderWriter for this MIME type.
func (r *entityReaderWriters) accessorAt(mime string) (EntityReaderWriter, bool) {
r.protection.RLock()
defer r.protection.RUnlock()
er, ok := r.accessors[mime]
if !ok {
// retry with reverse lookup
// more expensive but we are in an exceptional situation anyway
for k, v := range r.accessors {
if strings.Contains(mime, k) {
return v, true
}
}
}
return er, ok
}
// entityXMLAccess is a EntityReaderWriter for XML encoding
type entityXMLAccess struct {
// This is used for setting the Content-Type header when writing
ContentType string
}
// Read unmarshalls the value from XML
func (e entityXMLAccess) Read(req *Request, v interface{}) error {
return xml.NewDecoder(req.Request.Body).Decode(v)
}
// Write marshalls the value to JSON and set the Content-Type Header.
func (e entityXMLAccess) Write(resp *Response, status int, v interface{}) error {
return writeXML(resp, status, e.ContentType, v)
}
// writeXML marshalls the value to JSON and set the Content-Type Header.
func writeXML(resp *Response, status int, contentType string, v interface{}) error {
if v == nil {
resp.WriteHeader(status)
// do not write a nil representation
return nil
}
if resp.prettyPrint {
// pretty output must be created and written explicitly
output, err := xml.MarshalIndent(v, " ", " ")
if err != nil {
return err
}
resp.Header().Set(HEADER_ContentType, contentType)
resp.WriteHeader(status)
_, err = resp.Write([]byte(xml.Header))
if err != nil {
return err
}
_, err = resp.Write(output)
return err
}
// not-so-pretty
resp.Header().Set(HEADER_ContentType, contentType)
resp.WriteHeader(status)
return xml.NewEncoder(resp).Encode(v)
}
// entityJSONAccess is a EntityReaderWriter for JSON encoding
type entityJSONAccess struct {
// This is used for setting the Content-Type header when writing
ContentType string
}
// Read unmarshalls the value from JSON
func (e entityJSONAccess) Read(req *Request, v interface{}) error {
decoder := NewDecoder(req.Request.Body)
decoder.UseNumber()
return decoder.Decode(v)
}
// Write marshalls the value to JSON and set the Content-Type Header.
func (e entityJSONAccess) Write(resp *Response, status int, v interface{}) error {
return writeJSON(resp, status, e.ContentType, v)
}
// write marshalls the value to JSON and set the Content-Type Header.
func writeJSON(resp *Response, status int, contentType string, v interface{}) error {
if v == nil {
resp.WriteHeader(status)
// do not write a nil representation
return nil
}
if resp.prettyPrint {
// pretty output must be created and written explicitly
output, err := MarshalIndent(v, "", " ")
if err != nil {
return err
}
resp.Header().Set(HEADER_ContentType, contentType)
resp.WriteHeader(status)
_, err = resp.Write(output)
return err
}
// not-so-pretty
resp.Header().Set(HEADER_ContentType, contentType)
resp.WriteHeader(status)
return NewEncoder(resp).Encode(v)
}