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
|
// Copyright 2018, the Blazer authors
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package pyre
import (
"fmt"
"io"
"net/http"
"strconv"
"strings"
)
type DownloadableObject interface {
Size() int64
Reader() io.ReaderAt
io.Closer
}
type DownloadManager interface {
ObjectByName(bucketID, name string) (DownloadableObject, error)
GetBucketID(bucket string) (string, error)
GetBucket(id string) ([]byte, error)
}
type downloadServer struct {
dm DownloadManager
}
type downloadRequest struct {
off, n int64
}
func parseDownloadHeaders(r *http.Request) (*downloadRequest, error) {
rang := r.Header.Get("Range")
if rang == "" {
return &downloadRequest{}, nil
}
if !strings.HasPrefix(rang, "bytes=") {
return nil, fmt.Errorf("unknown range format: %q", rang)
}
rang = strings.TrimPrefix(rang, "bytes=")
if !strings.Contains(rang, "-") {
return nil, fmt.Errorf("unknown range format: %q", rang)
}
parts := strings.Split(rang, "-")
off, err := strconv.ParseInt(parts[0], 10, 64)
if err != nil {
return nil, err
}
end, err := strconv.ParseInt(parts[1], 10, 64)
if err != nil {
return nil, err
}
return &downloadRequest{
off: off,
n: (end + 1) - off,
}, nil
}
func (fs *downloadServer) serveWholeObject(rw http.ResponseWriter, obj DownloadableObject) {
rw.Header().Set("Content-Length", fmt.Sprintf("%d", obj.Size()))
sr := io.NewSectionReader(obj.Reader(), 0, obj.Size())
if _, err := io.Copy(rw, sr); err != nil {
http.Error(rw, err.Error(), 503)
fmt.Println("no reader", err)
}
}
func (fs *downloadServer) servePartialObject(rw http.ResponseWriter, obj DownloadableObject, off, len int64) {
if off >= obj.Size() {
http.Error(rw, "hell naw", 416)
fmt.Printf("range not good (%d-%d for %d)\n", off, len, obj.Size())
return
}
if off+len > obj.Size() {
len = obj.Size() - off
}
sr := io.NewSectionReader(obj.Reader(), off, len)
rw.Header().Set("Content-Length", fmt.Sprintf("%d", len))
rw.WriteHeader(206) // this goes after headers are set
if _, err := io.Copy(rw, sr); err != nil {
fmt.Println("bad read:", err)
}
}
func (fs *downloadServer) ServeHTTP(rw http.ResponseWriter, r *http.Request) {
req, err := parseDownloadHeaders(r)
if err != nil {
http.Error(rw, err.Error(), 503)
fmt.Println("weird header")
return
}
path := strings.TrimPrefix(r.URL.Path, "/")
parts := strings.Split(path, "/")
if len(parts) < 3 {
http.Error(rw, err.Error(), 404)
fmt.Println("weird file")
return
}
bucket := parts[1]
bid, err := fs.dm.GetBucketID(bucket)
if err != nil {
http.Error(rw, err.Error(), 503)
fmt.Println("no bucket:", err)
return
}
file := strings.Join(parts[2:], "/")
obj, err := fs.dm.ObjectByName(bid, file)
if err != nil {
http.Error(rw, err.Error(), 503)
fmt.Println("no reader", err)
return
}
defer obj.Close()
if req.off == 0 && req.n == 0 {
fs.serveWholeObject(rw, obj)
return
}
fs.servePartialObject(rw, obj, req.off, req.n)
}
func RegisterDownloadManagerOnMux(d DownloadManager, mux *http.ServeMux) {
mux.Handle("/file/", &downloadServer{dm: d})
}
|
