forked from carl-mastrangelo/pixur
-
Notifications
You must be signed in to change notification settings - Fork 1
/
compressor.go
97 lines (84 loc) · 2.2 KB
/
compressor.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
package handlers
import (
"compress/gzip"
"io"
"net/http"
"strings"
)
var _ http.Handler = &compressionHandler{}
type compressionHandler struct {
next http.Handler
}
func (h *compressionHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
for _, enc := range strings.Split(r.Header.Get("Accept-Encoding"), ",") {
if strings.TrimSpace(enc) == "gzip" {
if gw, err := gzip.NewWriterLevel(w, gzip.BestSpeed); err != nil {
httpError(w, err)
} else {
crw := &compressingResponseWriter{delegate: w, writer: gw}
defer crw.Close()
h.next.ServeHTTP(crw, r)
}
return
}
}
h.next.ServeHTTP(w, r)
}
var _ http.ResponseWriter = &compressingResponseWriter{}
var _ http.Flusher = &compressingResponseWriter{}
var _ http.Pusher = &compressingResponseWriter{}
type compressingResponseWriter struct {
delegate http.ResponseWriter
writer io.Writer
whcalled bool
}
func (rw *compressingResponseWriter) Header() http.Header {
return rw.delegate.Header()
}
func (rw *compressingResponseWriter) Write(data []byte) (int, error) {
if !rw.whcalled {
rw.WriteHeader(http.StatusOK)
}
return rw.writer.Write(data)
}
func (rw *compressingResponseWriter) WriteHeader(code int) {
if !rw.whcalled {
rw.whcalled = true
header := rw.Header()
if header.Get("Content-Encoding") == "" && rw.writer != nil {
header.Set("Content-Encoding", "gzip")
} else {
rw.writer = rw.delegate
}
}
rw.delegate.WriteHeader(code)
}
func (rw *compressingResponseWriter) Flush() {
type errflusher interface {
Flush() error
}
switch f := rw.writer.(type) {
case http.Flusher:
f.Flush()
case errflusher:
if err := f.Flush(); err != nil {
httpError(rw, err)
return
}
}
// maybe log this?
}
func (rw *compressingResponseWriter) Push(target string, opts *http.PushOptions) error {
if pusher, ok := rw.delegate.(http.Pusher); ok {
return pusher.Push(target, opts)
}
return http.ErrNotSupported
}
// Close should be called after the ServeHTTP method returns, per net/http:
// "A ResponseWriter may not be used after the Handler.ServeHTTP method has returned."
func (rw *compressingResponseWriter) Close() error {
if closer, ok := rw.writer.(io.Closer); ok {
return closer.Close()
}
return nil
}