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
|
// Copyright 2015 Google Inc. All rights reserved.
//
// 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 proxyauth provides authentication support via the
// Proxy-Authorization header.
package proxyauth
import (
"encoding/base64"
"net/http"
"strings"
"github.com/google/martian/v3"
"github.com/google/martian/v3/auth"
)
var noop = martian.Noop("proxyauth.Modifier")
// Modifier is the proxy authentication modifier.
type Modifier struct {
reqmod martian.RequestModifier
resmod martian.ResponseModifier
}
// NewModifier returns a new proxy authentication modifier.
func NewModifier() *Modifier {
return &Modifier{
reqmod: noop,
resmod: noop,
}
}
// SetRequestModifier sets the request modifier.
func (m *Modifier) SetRequestModifier(reqmod martian.RequestModifier) {
if reqmod == nil {
reqmod = noop
}
m.reqmod = reqmod
}
// SetResponseModifier sets the response modifier.
func (m *Modifier) SetResponseModifier(resmod martian.ResponseModifier) {
if resmod == nil {
resmod = noop
}
m.resmod = resmod
}
// ModifyRequest sets the auth ID in the context from the request iff it has
// not already been set and runs reqmod.ModifyRequest. If the underlying
// modifier has indicated via auth error that no valid auth credentials
// have been found we set ctx.SkipRoundTrip.
func (m *Modifier) ModifyRequest(req *http.Request) error {
ctx := martian.NewContext(req)
actx := auth.FromContext(ctx)
actx.SetID(id(req.Header))
err := m.reqmod.ModifyRequest(req)
if actx.Error() != nil {
ctx.SkipRoundTrip()
}
return err
}
// ModifyResponse runs resmod.ModifyResponse and modifies the response to
// include the correct status code and headers if auth error is present.
//
// If an error is returned from resmod.ModifyResponse it is returned.
func (m *Modifier) ModifyResponse(res *http.Response) error {
ctx := martian.NewContext(res.Request)
actx := auth.FromContext(ctx)
err := m.resmod.ModifyResponse(res)
if actx.Error() != nil {
res.StatusCode = http.StatusProxyAuthRequired
res.Header.Set("Proxy-Authenticate", "Basic")
}
return err
}
// id returns an ID derived from the Proxy-Authorization header username and password.
func id(header http.Header) string {
id := strings.TrimPrefix(header.Get("Proxy-Authorization"), "Basic ")
data, err := base64.StdEncoding.DecodeString(id)
if err != nil {
return ""
}
return string(data)
}
|
