forked from google/martian
-
Notifications
You must be signed in to change notification settings - Fork 0
/
port_modifier.go
159 lines (139 loc) · 4.6 KB
/
port_modifier.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
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
// 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 port
import (
"encoding/json"
"fmt"
"net"
"net/http"
"strconv"
"strings"
"github.com/google/martian/parse"
)
func init() {
parse.Register("port.Modifier", modifierFromJSON)
}
// Modifier alters the request URL and Host header to use the provided port.
// Only one of port, defaultForScheme, or remove may be specified. Whichever is set last is the one that will take effect.
// If remove is true, remove the port from the host string ('example.com').
// If defaultForScheme is true, explicitly specify 80 for HTTP or 443 for HTTPS ('http://example.com:80'). Do nothing for a scheme that is not 'http' or 'https'.
// If port is specified, explicitly add it to the host string ('example.com:1234').
// If port is zero and the other fields are false, the request will not be modified.
type Modifier struct {
port int
defaultForScheme bool
remove bool
}
type modifierJSON struct {
Port int `json:"port"`
DefaultForScheme bool `json:"defaultForScheme"`
Remove bool `json:"remove"`
Scope []parse.ModifierType `json:"scope"`
}
// NewModifier returns a RequestModifier that can be configured to alter the request URL and Host header's port.
// One of DefaultPortForScheme, UsePort, or RemovePort should be called to configure this modifier.
func NewModifier() *Modifier {
return &Modifier{}
}
// DefaultPortForScheme configures the modifier to explicitly specify 80 for HTTP or 443 for HTTPS ('http://example.com:80').
// The modifier will not modify requests with a scheme that is not 'http' or 'https'.
// This overrides any previous configuration for this modifier.
func (m *Modifier) DefaultPortForScheme() {
m.defaultForScheme = true
m.remove = false
}
// UsePort configures the modifier to add the specified port to the host string ('example.com:1234').
// This overrides any previous configuration for this modifier.
func (m *Modifier) UsePort(port int) {
m.port = port
m.remove = false
m.defaultForScheme = false
}
// RemovePort configures the modifier to remove the port from the host string ('example.com').
// This overrides any previous configuration for this modifier.
func (m *Modifier) RemovePort() {
m.remove = true
m.defaultForScheme = false
}
// ModifyRequest alters the request URL and Host header to modify the port as specified.
// See docs for Modifier for details.
func (m *Modifier) ModifyRequest(req *http.Request) error {
if m.port == 0 && !m.defaultForScheme && !m.remove {
return nil
}
host := req.URL.Host
if strings.Contains(host, ":") {
h, _, err := net.SplitHostPort(host)
if err != nil {
return err
}
host = h
}
if m.remove {
req.URL.Host = host
req.Header.Set("Host", host)
return nil
}
if m.defaultForScheme {
switch req.URL.Scheme {
case "http":
hp := net.JoinHostPort(host, "80")
req.URL.Host = hp
req.Header.Set("Host", hp)
return nil
case "https":
hp := net.JoinHostPort(host, "443")
req.URL.Host = hp
req.Header.Set("Host", hp)
return nil
default:
// Unknown scheme, do nothing.
return nil
}
}
// Not removing or using default for the scheme, so use the provided port number.
hp := net.JoinHostPort(host, strconv.Itoa(m.port))
req.URL.Host = hp
req.Header.Set("Host", hp)
return nil
}
func modifierFromJSON(b []byte) (*parse.Result, error) {
msg := &modifierJSON{}
if err := json.Unmarshal(b, msg); err != nil {
return nil, err
}
errMsg := fmt.Errorf("Must specify only one of port, defaultForScheme or remove")
mod := NewModifier()
// Check that exactly one field of port, defaultForScheme, and remove is set.
switch {
case msg.Port != 0:
if msg.DefaultForScheme || msg.Remove {
return nil, errMsg
}
mod.UsePort(msg.Port)
case msg.DefaultForScheme:
if msg.Port != 0 || msg.Remove {
return nil, errMsg
}
mod.DefaultPortForScheme()
case msg.Remove:
if msg.Port != 0 || msg.DefaultForScheme {
return nil, errMsg
}
mod.RemovePort()
default:
return nil, errMsg
}
return parse.NewResult(mod, msg.Scope)
}