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
|
// Copyright (c) 2020 Tailscale Inc & AUTHORS All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package tsweb
import (
"encoding/json"
"fmt"
"net/http"
)
type response struct {
Status string `json:"status"`
Error string `json:"error,omitempty"`
Data interface{} `json:"data,omitempty"`
}
// JSONHandlerFunc is an HTTP ReturnHandler that writes JSON responses to the client.
//
// Return a HTTPError to show an error message, otherwise JSONHandlerFunc will
// only report "internal server error" to the user with status code 500.
type JSONHandlerFunc func(r *http.Request) (status int, data interface{}, err error)
// ServeHTTPReturn implements the ReturnHandler interface.
//
// Use the following code to unmarshal the request body
//
// body := new(DataType)
// if err := json.NewDecoder(r.Body).Decode(body); err != nil {
// return http.StatusBadRequest, nil, err
// }
//
// See jsonhandler_test.go for examples.
func (fn JSONHandlerFunc) ServeHTTPReturn(w http.ResponseWriter, r *http.Request) error {
w.Header().Set("Content-Type", "application/json")
var resp *response
status, data, err := fn(r)
if err != nil {
if werr, ok := err.(HTTPError); ok {
resp = &response{
Status: "error",
Error: werr.Msg,
Data: data,
}
// Unwrap the HTTPError here because we are communicating with
// the client in this handler. We don't want the wrapping
// ReturnHandler to do it too.
err = werr.Err
if werr.Msg != "" {
err = fmt.Errorf("%s: %w", werr.Msg, err)
}
// take status from the HTTPError to encourage error handling in one location
if status != 0 && status != werr.Code {
err = fmt.Errorf("[unexpected] non-zero status that does not match HTTPError status, status: %d, HTTPError.code: %d: %w", status, werr.Code, err)
}
status = werr.Code
} else {
status = http.StatusInternalServerError
resp = &response{
Status: "error",
Error: "internal server error",
}
}
} else if status == 0 {
status = http.StatusInternalServerError
resp = &response{
Status: "error",
Error: "internal server error",
}
} else if err == nil {
resp = &response{
Status: "success",
Data: data,
}
}
b, jerr := json.Marshal(resp)
if jerr != nil {
w.WriteHeader(http.StatusInternalServerError)
w.Write([]byte(`{"status":"error","error":"json marshal error"}`))
if err != nil {
return fmt.Errorf("%w, and then we could not respond: %v", err, jerr)
}
return jerr
}
w.WriteHeader(status)
w.Write(b)
return err
}
// TODO() Set this function such that chunk encoding works
// Currently the same thing with chunking headers set.
func (fn JSONHandlerFunc) ServeHTTPChunkEncodingReturn(w http.ResponseWriter, r *http.Request) error {
w.Header().Set("Connection", "Keep-Alive")
w.Header().Set("Transfer-Encoding", "chunked")
w.Header().Set("X-Content-Type-Options", "nosniff")
var resp *response
status, data, err := fn(r)
if err != nil {
if werr, ok := err.(HTTPError); ok {
resp = &response{
Status: "error",
Error: werr.Msg,
Data: data,
}
// Unwrap the HTTPError here because we are communicating with
// the client in this handler. We don't want the wrapping
// ReturnHandler to do it too.
err = werr.Err
if werr.Msg != "" {
err = fmt.Errorf("%s: %w", werr.Msg, err)
}
// take status from the HTTPError to encourage error handling in one location
if status != 0 && status != werr.Code {
err = fmt.Errorf("[unexpected] non-zero status that does not match HTTPError status, status: %d, HTTPError.code: %d: %w", status, werr.Code, err)
}
status = werr.Code
} else {
status = http.StatusInternalServerError
resp = &response{
Status: "error",
Error: "internal server error",
}
}
} else if status == 0 {
status = http.StatusInternalServerError
resp = &response{
Status: "error",
Error: "internal server error",
}
} else if err == nil {
resp = &response{
Status: "success",
Data: data,
}
}
b, jerr := json.Marshal(resp)
if jerr != nil {
w.WriteHeader(http.StatusInternalServerError)
w.Write([]byte(`{"status":"error","error":"json marshal error"}`))
if err != nil {
return fmt.Errorf("%w, and then we could not respond: %v", err, jerr)
}
return jerr
}
w.WriteHeader(status)
w.Write(b)
return err
}
|
