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
177
178
179
180
181
182
183
|
// Copyright 2019 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.
// Package sumweb implements the HTTP protocols for serving or accessing a go.sum database.
package sumweb
import (
"context"
"internal/lazyregexp"
"net/http"
"os"
"strings"
"cmd/go/internal/tlog"
)
// A Server provides the external operations
// (underlying database access and so on)
// needed to implement the HTTP server Handler.
type Server interface {
// NewContext returns the context to use for the request r.
NewContext(r *http.Request) (context.Context, error)
// Signed returns the signed hash of the latest tree.
Signed(ctx context.Context) ([]byte, error)
// ReadRecords returns the content for the n records id through id+n-1.
ReadRecords(ctx context.Context, id, n int64) ([][]byte, error)
// Lookup looks up a record by its associated key ("module@version"),
// returning the record ID.
Lookup(ctx context.Context, key string) (int64, error)
// ReadTileData reads the content of tile t.
// It is only invoked for hash tiles (t.L ≥ 0).
ReadTileData(ctx context.Context, t tlog.Tile) ([]byte, error)
}
// A Handler is the go.sum database server handler,
// which should be invoked to serve the paths listed in Paths.
// The calling code is responsible for initializing Server.
type Handler struct {
Server Server
}
// Paths are the URL paths for which Handler should be invoked.
//
// Typically a server will do:
//
// handler := &sumweb.Handler{Server: srv}
// for _, path := range sumweb.Paths {
// http.HandleFunc(path, handler)
// }
//
var Paths = []string{
"/lookup/",
"/latest",
"/tile/",
}
var modVerRE = lazyregexp.New(`^[^@]+@v[0-9]+\.[0-9]+\.[0-9]+(-[^@]*)?(\+incompatible)?$`)
func (h *Handler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
ctx, err := h.Server.NewContext(r)
if err != nil {
http.Error(w, err.Error(), 500)
return
}
switch {
default:
http.NotFound(w, r)
case strings.HasPrefix(r.URL.Path, "/lookup/"):
mod := strings.TrimPrefix(r.URL.Path, "/lookup/")
if !modVerRE.MatchString(mod) {
http.Error(w, "invalid module@version syntax", http.StatusBadRequest)
return
}
i := strings.Index(mod, "@")
encPath, encVers := mod[:i], mod[i+1:]
path, err := decodePath(encPath)
if err != nil {
reportError(w, r, err)
return
}
vers, err := decodeVersion(encVers)
if err != nil {
reportError(w, r, err)
return
}
id, err := h.Server.Lookup(ctx, path+"@"+vers)
if err != nil {
reportError(w, r, err)
return
}
records, err := h.Server.ReadRecords(ctx, id, 1)
if err != nil {
// This should never happen - the lookup says the record exists.
http.Error(w, err.Error(), http.StatusInternalServerError)
return
}
if len(records) != 1 {
http.Error(w, "invalid record count returned by ReadRecords", http.StatusInternalServerError)
return
}
msg, err := tlog.FormatRecord(id, records[0])
if err != nil {
http.Error(w, err.Error(), http.StatusInternalServerError)
return
}
signed, err := h.Server.Signed(ctx)
if err != nil {
http.Error(w, err.Error(), http.StatusInternalServerError)
return
}
w.Header().Set("Content-Type", "text/plain; charset=UTF-8")
w.Write(msg)
w.Write(signed)
case r.URL.Path == "/latest":
data, err := h.Server.Signed(ctx)
if err != nil {
http.Error(w, err.Error(), http.StatusInternalServerError)
return
}
w.Header().Set("Content-Type", "text/plain; charset=UTF-8")
w.Write(data)
case strings.HasPrefix(r.URL.Path, "/tile/"):
t, err := tlog.ParseTilePath(r.URL.Path[1:])
if err != nil {
http.Error(w, "invalid tile syntax", http.StatusBadRequest)
return
}
if t.L == -1 {
// Record data.
start := t.N << uint(t.H)
records, err := h.Server.ReadRecords(ctx, start, int64(t.W))
if err != nil {
reportError(w, r, err)
return
}
if len(records) != t.W {
http.Error(w, "invalid record count returned by ReadRecords", http.StatusInternalServerError)
return
}
var data []byte
for i, text := range records {
msg, err := tlog.FormatRecord(start+int64(i), text)
if err != nil {
http.Error(w, err.Error(), http.StatusInternalServerError)
}
data = append(data, msg...)
}
w.Header().Set("Content-Type", "text/plain; charset=UTF-8")
w.Write(data)
return
}
data, err := h.Server.ReadTileData(ctx, t)
if err != nil {
reportError(w, r, err)
return
}
w.Header().Set("Content-Type", "application/octet-stream")
w.Write(data)
}
}
// reportError reports err to w.
// If it's a not-found, the reported error is 404.
// Otherwise it is an internal server error.
// The caller must only call reportError in contexts where
// a not-found err should be reported as 404.
func reportError(w http.ResponseWriter, r *http.Request, err error) {
if os.IsNotExist(err) {
http.Error(w, err.Error(), http.StatusNotFound)
return
}
http.Error(w, err.Error(), http.StatusInternalServerError)
}
|
