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
|
package gemini
import (
"bufio"
"context"
"crypto/tls"
"crypto/x509"
"net"
"net/url"
"strings"
"time"
)
// Client is a Gemini client.
type Client struct {
// TrustCertificate is called to determine whether the client
// should trust the certificate provided by the server.
// If TrustCertificate is nil, the client will accept any certificate.
// If the returned error is not nil, the certificate will not be trusted
// and the request will be aborted.
TrustCertificate func(hostname string, cert *x509.Certificate) error
// GetCertificate is called to retrieve a certificate upon
// the request of a server.
// If GetCertificate is nil or the returned error is not nil,
// the request will not be sent again and the response will be returned.
GetCertificate func(scope, path string) (tls.Certificate, error)
// GetInput is called to retrieve input when the server requests it.
// If GetInput is nil or returns false, no input will be sent and
// the response will be returned.
GetInput func(prompt string, sensitive bool) (input string, ok bool)
// CheckRedirect determines whether to follow a redirect.
// If CheckRedirect is nil, redirects will not be followed.
CheckRedirect func(req *Request, via []*Request) error
// Timeout specifies a time limit for requests made by this
// Client. The timeout includes connection time and reading
// the response body. The timer remains running after
// Get and Do return and will interrupt reading of the Response.Body.
//
// A Timeout of zero means no timeout.
Timeout time.Duration
}
// Get performs a Gemini request for the given URL.
func (c *Client) Get(url string) (*Response, error) {
req, err := NewRequest(url)
if err != nil {
return nil, err
}
return c.Do(req)
}
// Do performs a Gemini request and returns a Gemini response.
func (c *Client) Do(req *Request) (*Response, error) {
return c.do(req, nil)
}
func (c *Client) do(req *Request, via []*Request) (*Response, error) {
// Extract hostname
colonPos := strings.LastIndex(req.Host, ":")
if colonPos == -1 {
colonPos = len(req.Host)
}
hostname := req.Host[:colonPos]
// Connect to the host
config := &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(req, cs)
},
ServerName: hostname,
}
ctx := req.Context
if ctx == nil {
ctx = context.Background()
}
netConn, err := (&net.Dialer{}).DialContext(ctx, "tcp", req.Host)
if err != nil {
return nil, err
}
conn := tls.Client(netConn, config)
// Set connection deadline
if d := c.Timeout; d != 0 {
conn.SetDeadline(time.Now().Add(d))
}
// Write the request
w := bufio.NewWriter(conn)
req.write(w)
if err := w.Flush(); err != nil {
return nil, err
}
// Read the response
resp := &Response{}
if err := resp.read(conn); err != nil {
return nil, err
}
resp.Request = req
// Store connection state
resp.TLS = conn.ConnectionState()
switch {
case resp.Status == StatusCertificateRequired:
if c.GetCertificate == nil {
break
}
// Check to see if a certificate was already provided to prevent an infinite loop
if req.Certificate != nil {
break
}
hostname, path := req.URL.Hostname(), strings.TrimSuffix(req.URL.Path, "/")
cert, err := c.GetCertificate(hostname, path)
if err != nil {
return resp, err
}
req.Certificate = &cert
return c.do(req, via)
case resp.Status.Class() == StatusClassInput:
if c.GetInput == nil {
break
}
input, ok := c.GetInput(resp.Meta, resp.Status == StatusSensitiveInput)
if ok {
req.URL.ForceQuery = true
req.URL.RawQuery = QueryEscape(input)
return c.do(req, via)
}
case resp.Status.Class() == StatusClassRedirect:
if c.CheckRedirect == nil {
break
}
if via == nil {
via = []*Request{}
}
via = append(via, req)
target, err := url.Parse(resp.Meta)
if err != nil {
return resp, err
}
target = req.URL.ResolveReference(target)
redirect := NewRequestFromURL(target)
redirect.Context = req.Context
if err := c.CheckRedirect(redirect, via); err != nil {
return resp, err
}
return c.do(redirect, via)
}
return resp, nil
}
func (c *Client) verifyConnection(req *Request, cs tls.ConnectionState) error {
// Verify the hostname
var hostname string
if host, _, err := net.SplitHostPort(req.Host); err == nil {
hostname = host
} else {
hostname = req.Host
}
cert := cs.PeerCertificates[0]
if err := verifyHostname(cert, hostname); err != nil {
return err
}
// See if the client trusts the certificate
if c.TrustCertificate != nil {
return c.TrustCertificate(hostname, cert)
}
return nil
}
|