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
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
|
package gemini
import (
"context"
"crypto/tls"
"crypto/x509"
"net"
"net/url"
"unicode/utf8"
"golang.org/x/net/idna"
)
// A Client is a Gemini client. Its zero value is a usable client.
type Client struct {
// TrustCertificate is called to determine whether the client should
// trust the certificate provided by the server.
// If TrustCertificate is nil or returns nil, the client will accept
// any certificate. Otherwise, the certificate will not be trusted
// and the request will be aborted.
//
// See the tofu submodule for an implementation of trust on first use.
TrustCertificate func(hostname string, cert *x509.Certificate) error
// DialContext specifies the dial function for creating TCP connections.
// If DialContext is nil, the client dials using package net.
DialContext func(ctx context.Context, network, addr string) (net.Conn, error)
}
// Get sends a Gemini request for the given URL.
// The context controls the entire lifetime of a request and its response:
// obtaining a connection, sending the request, and reading the response
// header and body.
//
// An error is returned if there was a Gemini protocol error.
// A non-2x status code doesn't cause an error.
//
// If the returned error is nil, the user is expected to close the Response.
//
// For more control over requests, use NewRequest and Client.Do.
func (c *Client) Get(ctx context.Context, url string) (*Response, error) {
req, err := NewRequest(url)
if err != nil {
return nil, err
}
return c.Do(ctx, req)
}
// Do sends a Gemini request and returns a Gemini response.
// The context controls the entire lifetime of a request and its response:
// obtaining a connection, sending the request, and reading the response
// header and body.
//
// An error is returned if there was a Gemini protocol error.
// A non-2x status code doesn't cause an error.
//
// If the returned error is nil, the user is expected to close the Response.
func (c *Client) Do(ctx context.Context, req *Request) (*Response, error) {
if ctx == nil {
panic("nil context")
}
// Punycode request URL host
host, port := splitHostPort(req.URL.Host)
punycode, err := punycodeHostname(host)
if err != nil {
return nil, err
}
if host != punycode {
host = punycode
// Copy the URL and update the host
u := new(url.URL)
*u = *req.URL
u.Host = net.JoinHostPort(host, port)
// Use the new URL in the request so that the server gets
// the punycoded hostname
r := new(Request)
*r = *req
r.URL = u
req = r
}
// Use request host if provided
if req.Host != "" {
host, port = splitHostPort(req.Host)
host, err = punycodeHostname(host)
if err != nil {
return nil, err
}
}
addr := net.JoinHostPort(host, port)
// Connect to the host
conn, err := c.dialContext(ctx, "tcp", addr)
if err != nil {
return nil, err
}
// Setup TLS
conn = tls.Client(conn, &tls.Config{
InsecureSkipVerify: true,
MinVersion: tls.VersionTLS12,
GetClientCertificate: func(_ *tls.CertificateRequestInfo) (*tls.Certificate, error) {
if req.Certificate != nil {
return req.Certificate, nil
}
return &tls.Certificate{}, nil
},
VerifyConnection: func(cs tls.ConnectionState) error {
return c.verifyConnection(cs, host)
},
ServerName: host,
})
type result struct {
resp *Response
err error
}
res := make(chan result, 1)
go func() {
resp, err := c.do(ctx, conn, req)
res <- result{resp, err}
}()
select {
case <-ctx.Done():
conn.Close()
return nil, ctx.Err()
case r := <-res:
if r.err != nil {
conn.Close()
}
return r.resp, r.err
}
}
func (c *Client) do(ctx context.Context, conn net.Conn, req *Request) (*Response, error) {
ctx, cancel := context.WithCancel(ctx)
done := ctx.Done()
w := &contextWriter{
ctx: ctx,
done: done,
cancel: cancel,
wc: conn,
}
rc := &contextReader{
ctx: ctx,
done: done,
cancel: cancel,
rc: conn,
}
// Write the request
if _, err := req.WriteTo(w); err != nil {
return nil, err
}
// Read the response
resp, err := ReadResponse(rc)
if err != nil {
return nil, err
}
resp.conn = conn
return resp, nil
}
func (c *Client) dialContext(ctx context.Context, network, addr string) (net.Conn, error) {
if c.DialContext != nil {
return c.DialContext(ctx, network, addr)
}
return (&net.Dialer{}).DialContext(ctx, network, addr)
}
func (c *Client) verifyConnection(cs tls.ConnectionState, hostname string) error {
// See if the client trusts the certificate
if c.TrustCertificate != nil {
cert := cs.PeerCertificates[0]
return c.TrustCertificate(hostname, cert)
}
return nil
}
func splitHostPort(hostport string) (host, port string) {
var err error
host, port, err = net.SplitHostPort(hostport)
if err != nil {
// Likely no port
host = hostport
port = "1965"
}
return
}
func isASCII(s string) bool {
for i := 0; i < len(s); i++ {
if s[i] >= utf8.RuneSelf {
return false
}
}
return true
}
// punycodeHostname returns the punycoded version of hostname.
func punycodeHostname(hostname string) (string, error) {
if net.ParseIP(hostname) != nil {
return hostname, nil
}
if isASCII(hostname) {
return hostname, nil
}
return idna.Lookup.ToASCII(hostname)
}
|