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
164
165
166
167
|
package headers
import (
"errors"
"net/http"
"strconv"
"strings"
"time"
"github.com/ydb-platform/ydb/library/go/core/xerrors"
)
const (
WarningKey = "Warning"
WarningResponseIsStale = 110 // RFC 7234, 5.5.1
WarningRevalidationFailed = 111 // RFC 7234, 5.5.2
WarningDisconnectedOperation = 112 // RFC 7234, 5.5.3
WarningHeuristicExpiration = 113 // RFC 7234, 5.5.4
WarningMiscellaneousWarning = 199 // RFC 7234, 5.5.5
WarningTransformationApplied = 214 // RFC 7234, 5.5.6
WarningMiscellaneousPersistentWarning = 299 // RFC 7234, 5.5.7
)
var warningStatusText = map[int]string{
WarningResponseIsStale: "Response is Stale",
WarningRevalidationFailed: "Revalidation Failed",
WarningDisconnectedOperation: "Disconnected Operation",
WarningHeuristicExpiration: "Heuristic Expiration",
WarningMiscellaneousWarning: "Miscellaneous Warning",
WarningTransformationApplied: "Transformation Applied",
WarningMiscellaneousPersistentWarning: "Miscellaneous Persistent Warning",
}
// WarningText returns a text for the warning header code. It returns the empty
// string if the code is unknown.
func WarningText(warn int) string {
return warningStatusText[warn]
}
// AddWarning adds Warning to http.Header with proper formatting
// see: https://tools.ietf.org/html/rfc7234#section-5.5
func AddWarning(h http.Header, warn int, agent, reason string, date time.Time) {
values := make([]string, 0, 4)
values = append(values, strconv.Itoa(warn))
if agent != "" {
values = append(values, agent)
} else {
values = append(values, "-")
}
if reason != "" {
values = append(values, strconv.Quote(reason))
}
if !date.IsZero() {
values = append(values, strconv.Quote(date.Format(time.RFC1123)))
}
h.Add(WarningKey, strings.Join(values, " "))
}
type WarningHeader struct {
Code int
Agent string
Reason string
Date time.Time
}
// ParseWarnings reads and parses Warning headers from http.Header
func ParseWarnings(h http.Header) ([]WarningHeader, error) {
warnings, ok := h[WarningKey]
if !ok {
return nil, nil
}
res := make([]WarningHeader, 0, len(warnings))
for _, warn := range warnings {
wh, err := parseWarning(warn)
if err != nil {
return nil, xerrors.Errorf("cannot parse '%s' header: %w", warn, err)
}
res = append(res, wh)
}
return res, nil
}
func parseWarning(warn string) (WarningHeader, error) {
var res WarningHeader
// parse code
{
codeSP := strings.Index(warn, " ")
// fast path - code only warning
if codeSP == -1 {
code, err := strconv.Atoi(warn)
res.Code = code
return res, err
}
code, err := strconv.Atoi(warn[:codeSP])
if err != nil {
return WarningHeader{}, err
}
res.Code = code
warn = strings.TrimSpace(warn[codeSP+1:])
}
// parse agent
{
agentSP := strings.Index(warn, " ")
// fast path - no data after agent
if agentSP == -1 {
res.Agent = warn
return res, nil
}
res.Agent = warn[:agentSP]
warn = strings.TrimSpace(warn[agentSP+1:])
}
// parse reason
{
if len(warn) == 0 {
return res, nil
}
// reason must by quoted, so we search for second quote
reasonSP := strings.Index(warn[1:], `"`)
// fast path - bad reason
if reasonSP == -1 {
return WarningHeader{}, errors.New("bad reason formatting")
}
res.Reason = warn[1 : reasonSP+1]
warn = strings.TrimSpace(warn[reasonSP+2:])
}
// parse date
{
if len(warn) == 0 {
return res, nil
}
// optional date must by quoted, so we search for second quote
dateSP := strings.Index(warn[1:], `"`)
// fast path - bad date
if dateSP == -1 {
return WarningHeader{}, errors.New("bad date formatting")
}
dt, err := time.Parse(time.RFC1123, warn[1:dateSP+1])
if err != nil {
return WarningHeader{}, err
}
res.Date = dt
}
return res, nil
}
|
