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
|
package middleware
import (
"bufio"
"compress/gzip"
"io"
"io/ioutil"
"net"
"net/http"
"strings"
"sync"
"github.com/labstack/echo/v4"
)
type (
// GzipConfig defines the config for Gzip middleware.
GzipConfig struct {
// Skipper defines a function to skip middleware.
Skipper Skipper
// Gzip compression level.
// Optional. Default value -1.
Level int `yaml:"level"`
}
gzipResponseWriter struct {
io.Writer
http.ResponseWriter
wroteBody bool
}
)
const (
gzipScheme = "gzip"
)
var (
// DefaultGzipConfig is the default Gzip middleware config.
DefaultGzipConfig = GzipConfig{
Skipper: DefaultSkipper,
Level: -1,
}
)
// Gzip returns a middleware which compresses HTTP response using gzip compression
// scheme.
func Gzip() echo.MiddlewareFunc {
return GzipWithConfig(DefaultGzipConfig)
}
// GzipWithConfig return Gzip middleware with config.
// See: `Gzip()`.
func GzipWithConfig(config GzipConfig) echo.MiddlewareFunc {
// Defaults
if config.Skipper == nil {
config.Skipper = DefaultGzipConfig.Skipper
}
if config.Level == 0 {
config.Level = DefaultGzipConfig.Level
}
pool := gzipCompressPool(config)
return func(next echo.HandlerFunc) echo.HandlerFunc {
return func(c echo.Context) error {
if config.Skipper(c) {
return next(c)
}
res := c.Response()
res.Header().Add(echo.HeaderVary, echo.HeaderAcceptEncoding)
if strings.Contains(c.Request().Header.Get(echo.HeaderAcceptEncoding), gzipScheme) {
res.Header().Set(echo.HeaderContentEncoding, gzipScheme) // Issue #806
i := pool.Get()
w, ok := i.(*gzip.Writer)
if !ok {
return echo.NewHTTPError(http.StatusInternalServerError, i.(error).Error())
}
rw := res.Writer
w.Reset(rw)
grw := &gzipResponseWriter{Writer: w, ResponseWriter: rw}
defer func() {
if !grw.wroteBody {
if res.Header().Get(echo.HeaderContentEncoding) == gzipScheme {
res.Header().Del(echo.HeaderContentEncoding)
}
// We have to reset response to it's pristine state when
// nothing is written to body or error is returned.
// See issue #424, #407.
res.Writer = rw
w.Reset(ioutil.Discard)
}
w.Close()
pool.Put(w)
}()
res.Writer = grw
}
return next(c)
}
}
}
func (w *gzipResponseWriter) WriteHeader(code int) {
w.Header().Del(echo.HeaderContentLength) // Issue #444
w.ResponseWriter.WriteHeader(code)
}
func (w *gzipResponseWriter) Write(b []byte) (int, error) {
if w.Header().Get(echo.HeaderContentType) == "" {
w.Header().Set(echo.HeaderContentType, http.DetectContentType(b))
}
w.wroteBody = true
return w.Writer.Write(b)
}
func (w *gzipResponseWriter) Flush() {
w.Writer.(*gzip.Writer).Flush()
if flusher, ok := w.ResponseWriter.(http.Flusher); ok {
flusher.Flush()
}
}
func (w *gzipResponseWriter) Hijack() (net.Conn, *bufio.ReadWriter, error) {
return w.ResponseWriter.(http.Hijacker).Hijack()
}
func (w *gzipResponseWriter) Push(target string, opts *http.PushOptions) error {
if p, ok := w.ResponseWriter.(http.Pusher); ok {
return p.Push(target, opts)
}
return http.ErrNotSupported
}
func gzipCompressPool(config GzipConfig) sync.Pool {
return sync.Pool{
New: func() interface{} {
w, err := gzip.NewWriterLevel(ioutil.Discard, config.Level)
if err != nil {
return err
}
return w
},
}
}
|
