forked from Azure/azure-sdk-for-go
-
Notifications
You must be signed in to change notification settings - Fork 0
/
responder.go
163 lines (147 loc) · 5.69 KB
/
responder.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
163
package autorest
import (
"bytes"
"encoding/json"
"fmt"
"io"
"net/http"
)
// Responder is the interface that wraps the Respond method.
//
// Respond accepts and reacts to an http.Response. Implementations must ensure to not share or hold
// state since Responders may be shared and re-used.
type Responder interface {
Respond(*http.Response) error
}
// ResponderFunc is a method that implements the Responder interface.
type ResponderFunc func(*http.Response) error
// Respond implements the Responder interface on ResponderFunc.
func (rf ResponderFunc) Respond(r *http.Response) error {
return rf(r)
}
// RespondDecorator takes and possibly decorates, by wrapping, a Responder. Decorators may react to
// the http.Response and pass it along or, first, pass the http.Response along then react.
type RespondDecorator func(Responder) Responder
// CreateResponder creates, decorates, and returns a Responder. Without decorators, the returned
// Responder returns the passed http.Response unmodified. Responders may or may not be safe to share
// and re-used: It depends on the applied decorators. For example, a standard decorator that closes
// the response body is fine to share whereas a decorator that reads the body into a passed struct
// is not.
//
// To prevent memory leaks, ensure that at least one Responder closes the response body.
func CreateResponder(decorators ...RespondDecorator) Responder {
return DecorateResponder(
Responder(ResponderFunc(func(r *http.Response) error { return nil })),
decorators...)
}
// DecorateResponder accepts a Responder and a, possibly empty, set of RespondDecorators, which it
// applies to the Responder. Decorators are applied in the order received, but their affect upon the
// request depends on whether they are a pre-decorator (react to the http.Response and then pass it
// along) or a post-decorator (pass the http.Response along and then react).
func DecorateResponder(r Responder, decorators ...RespondDecorator) Responder {
for _, decorate := range decorators {
r = decorate(r)
}
return r
}
// Respond accepts an http.Response and a, possibly empty, set of RespondDecorators.
// It creates a Responder from the decorators it then applies to the passed http.Response.
func Respond(r *http.Response, decorators ...RespondDecorator) error {
if r == nil {
return nil
}
return CreateResponder(decorators...).Respond(r)
}
// ByIgnoring returns a RespondDecorator that ignores the passed http.Response passing it unexamined
// to the next RespondDecorator.
func ByIgnoring() RespondDecorator {
return func(r Responder) Responder {
return ResponderFunc(func(resp *http.Response) error {
return r.Respond(resp)
})
}
}
// ByClosing returns a RespondDecorator that first invokes the passed Responder after which it
// closes the response body. Since the passed Responder is invoked prior to closing the response
// body, the decorator may occur anywhere within the set.
func ByClosing() RespondDecorator {
return func(r Responder) Responder {
return ResponderFunc(func(resp *http.Response) error {
err := r.Respond(resp)
if resp != nil && resp.Body != nil {
resp.Body.Close()
}
return err
})
}
}
// ByClosingIfError returns a RespondDecorator that first invokes the passed Responder after which
// it closes the response if the passed Responder returns an error and the response body exists.
func ByClosingIfError() RespondDecorator {
return func(r Responder) Responder {
return ResponderFunc(func(resp *http.Response) error {
err := r.Respond(resp)
if err != nil && resp != nil && resp.Body != nil {
resp.Body.Close()
}
return err
})
}
}
// ByUnmarshallingJSON returns a RespondDecorator that decodes a JSON document returned in the
// response Body into the value pointed to by v.
func ByUnmarshallingJSON(v interface{}) RespondDecorator {
return func(r Responder) Responder {
return ResponderFunc(func(resp *http.Response) error {
err := r.Respond(resp)
if err == nil {
b := bytes.Buffer{}
d := json.NewDecoder(io.TeeReader(resp.Body, &b))
err = d.Decode(v)
if err != nil {
err = fmt.Errorf("Error (%v) occurred decoding JSON (\"%s\")", err, b.String())
}
}
return err
})
}
}
// WithErrorUnlessStatusCode returns a RespondDecorator that emits an error unless the response
// StatusCode is among the set passed. Since these are artificial errors, the response body
// may still require closing.
func WithErrorUnlessStatusCode(codes ...int) RespondDecorator {
return func(r Responder) Responder {
return ResponderFunc(func(resp *http.Response) error {
err := r.Respond(resp)
if err == nil && !ResponseHasStatusCode(resp, codes...) {
err = NewError("autorest", "WithErrorUnlessStatusCode", "%v %v failed with %s",
resp.Request.Method,
resp.Request.URL,
resp.Status)
}
return err
})
}
}
// WithErrorUnlessOK returns a RespondDecorator that emits an error if the response StatusCode is
// anything other than HTTP 200.
func WithErrorUnlessOK() RespondDecorator {
return WithErrorUnlessStatusCode(http.StatusOK)
}
// ExtractHeader extracts all values of the specified header from the http.Response. It returns an
// empty string slice if the passed http.Response is nil or the header does not exist.
func ExtractHeader(header string, resp *http.Response) []string {
if resp != nil && resp.Header != nil {
return resp.Header[http.CanonicalHeaderKey(header)]
}
return nil
}
// ExtractHeaderValue extracts the first value of the specified header from the http.Response. It
// returns an empty string if the passed http.Response is nil or the header does not exist.
func ExtractHeaderValue(header string, resp *http.Response) string {
h := ExtractHeader(header, resp)
if len(h) > 0 {
return h[0]
}
return ""
}