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
168
169
170
171
172
173
174
175
176
|
// Copyright 2009 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
// HTTP file system request handler
package http
import (
"fmt"
"io"
"mime"
"os"
"path"
"strings"
"time"
"utf8"
)
// Heuristic: b is text if it is valid UTF-8 and doesn't
// contain any unprintable ASCII or Unicode characters.
func isText(b []byte) bool {
for len(b) > 0 && utf8.FullRune(b) {
rune, size := utf8.DecodeRune(b)
if size == 1 && rune == utf8.RuneError {
// decoding error
return false
}
if 0x80 <= rune && rune <= 0x9F {
return false
}
if rune < ' ' {
switch rune {
case '\n', '\r', '\t':
// okay
default:
// binary garbage
return false
}
}
b = b[size:]
}
return true
}
func dirList(w ResponseWriter, f *os.File) {
fmt.Fprintf(w, "<pre>\n")
for {
dirs, err := f.Readdir(100)
if err != nil || len(dirs) == 0 {
break
}
for _, d := range dirs {
name := d.Name
if d.IsDirectory() {
name += "/"
}
// TODO htmlescape
fmt.Fprintf(w, "<a href=\"%s\">%s</a>\n", name, name)
}
}
fmt.Fprintf(w, "</pre>\n")
}
func serveFile(w ResponseWriter, r *Request, name string, redirect bool) {
const indexPage = "/index.html"
// redirect .../index.html to .../
if strings.HasSuffix(r.URL.Path, indexPage) {
Redirect(w, r, r.URL.Path[0:len(r.URL.Path)-len(indexPage)+1], StatusMovedPermanently)
return
}
f, err := os.Open(name, os.O_RDONLY, 0)
if err != nil {
// TODO expose actual error?
NotFound(w, r)
return
}
defer f.Close()
d, err1 := f.Stat()
if err1 != nil {
// TODO expose actual error?
NotFound(w, r)
return
}
if redirect {
// redirect to canonical path: / at end of directory url
// r.URL.Path always begins with /
url := r.URL.Path
if d.IsDirectory() {
if url[len(url)-1] != '/' {
Redirect(w, r, url+"/", StatusMovedPermanently)
return
}
} else {
if url[len(url)-1] == '/' {
Redirect(w, r, url[0:len(url)-1], StatusMovedPermanently)
return
}
}
}
if t, _ := time.Parse(TimeFormat, r.Header["If-Modified-Since"]); t != nil && d.Mtime_ns/1e9 <= t.Seconds() {
w.WriteHeader(StatusNotModified)
return
}
w.SetHeader("Last-Modified", time.SecondsToUTC(d.Mtime_ns/1e9).Format(TimeFormat))
// use contents of index.html for directory, if present
if d.IsDirectory() {
index := name + indexPage
ff, err := os.Open(index, os.O_RDONLY, 0)
if err == nil {
defer ff.Close()
dd, err := ff.Stat()
if err == nil {
name = index
d = dd
f = ff
}
}
}
if d.IsDirectory() {
dirList(w, f)
return
}
// serve file
// use extension to find content type.
ext := path.Ext(name)
if ctype := mime.TypeByExtension(ext); ctype != "" {
w.SetHeader("Content-Type", ctype)
} else {
// read first chunk to decide between utf-8 text and binary
var buf [1024]byte
n, _ := io.ReadFull(f, buf[0:])
b := buf[0:n]
if isText(b) {
w.SetHeader("Content-Type", "text-plain; charset=utf-8")
} else {
w.SetHeader("Content-Type", "application/octet-stream") // generic binary
}
w.Write(b)
}
io.Copy(w, f)
}
// ServeFile replies to the request with the contents of the named file or directory.
func ServeFile(w ResponseWriter, r *Request, name string) {
serveFile(w, r, name, false)
}
type fileHandler struct {
root string
prefix string
}
// FileServer returns a handler that serves HTTP requests
// with the contents of the file system rooted at root.
// It strips prefix from the incoming requests before
// looking up the file name in the file system.
func FileServer(root, prefix string) Handler { return &fileHandler{root, prefix} }
func (f *fileHandler) ServeHTTP(w ResponseWriter, r *Request) {
path := r.URL.Path
if !strings.HasPrefix(path, f.prefix) {
NotFound(w, r)
return
}
path = path[len(f.prefix):]
serveFile(w, r, f.root+"/"+path, true)
}
|
