/
handlers.go
235 lines (199 loc) · 5.68 KB
/
handlers.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
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
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
package server
import (
"bytes"
"context"
"encoding/json"
"fmt"
"log"
"net/http"
"net/url"
"sync/atomic"
"github.com/gorilla/websocket"
"github.com/pkg/errors"
"gotty/webtty"
)
func (server *Server) generateHandleWS(ctx context.Context, cancel context.CancelFunc, counter *counter) http.HandlerFunc {
once := new(int64)
go func() {
select {
case <-counter.timer().C:
cancel()
case <-ctx.Done():
}
}()
return func(w http.ResponseWriter, r *http.Request) {
if server.options.Once {
success := atomic.CompareAndSwapInt64(once, 0, 1)
if !success {
http.Error(w, "Server is shutting down", http.StatusServiceUnavailable)
return
}
}
num := counter.add(1)
closeReason := "unknown reason"
defer func() {
num := counter.done()
log.Printf(
"Connection closed by %s: %s, connections: %d/%d",
closeReason, r.RemoteAddr, num, server.options.MaxConnection,
)
if server.options.Once {
cancel()
}
}()
if int64(server.options.MaxConnection) != 0 {
if num > server.options.MaxConnection {
closeReason = "exceeding max number of connections"
return
}
}
log.Printf("New client connected: %s, connections: %d/%d", r.RemoteAddr, num, server.options.MaxConnection)
if r.Method != "GET" {
http.Error(w, "Method not allowed", 405)
return
}
conn, err := server.upgrader.Upgrade(w, r, nil)
if err != nil {
closeReason = err.Error()
return
}
defer conn.Close()
err = server.processWSConn(ctx, conn)
switch err {
case ctx.Err():
closeReason = "cancelation"
case webtty.ErrSlaveClosed:
closeReason = server.factory.Name()
case webtty.ErrMasterClosed:
closeReason = "client"
default:
closeReason = fmt.Sprintf("an error: %s", err)
}
}
}
func (server *Server) processWSConn(ctx context.Context, conn *websocket.Conn) error {
typ, initLine, err := conn.ReadMessage()
if err != nil {
return errors.Wrapf(err, "failed to authenticate websocket connection")
}
if typ != websocket.TextMessage {
return errors.New("failed to authenticate websocket connection: invalid message type")
}
var init InitMessage
err = json.Unmarshal(initLine, &init)
if err != nil {
return errors.Wrapf(err, "failed to authenticate websocket connection")
}
if init.AuthToken != server.options.Credential {
return errors.New("failed to authenticate websocket connection")
}
queryPath := "?"
if server.options.PermitArguments && init.Arguments != "" {
queryPath = init.Arguments
}
query, err := url.Parse(queryPath)
if err != nil {
return errors.Wrapf(err, "failed to parse arguments")
}
params := query.Query()
var slave Slave
slave, err = server.factory.New(params)
if err != nil {
return errors.Wrapf(err, "failed to create backend")
}
defer slave.Close()
titleVars := server.titleVariables(
[]string{"server", "master", "slave"},
map[string]map[string]interface{}{
"server": server.options.TitleVariables,
"master": map[string]interface{}{
"remote_addr": conn.RemoteAddr(),
},
"slave": slave.WindowTitleVariables(),
},
)
titleBuf := new(bytes.Buffer)
err = server.titleTemplate.Execute(titleBuf, titleVars)
if err != nil {
return errors.Wrapf(err, "failed to fill window title template")
}
opts := []webtty.Option{
webtty.WithWindowTitle(titleBuf.Bytes()),
}
if server.options.PermitWrite {
opts = append(opts, webtty.WithPermitWrite())
}
if server.options.EnableReconnect {
opts = append(opts, webtty.WithReconnect(server.options.ReconnectTime))
}
if server.options.Width > 0 {
opts = append(opts, webtty.WithFixedColumns(server.options.Width))
}
if server.options.Height > 0 {
opts = append(opts, webtty.WithFixedRows(server.options.Height))
}
if server.options.Preferences != nil {
opts = append(opts, webtty.WithMasterPreferences(server.options.Preferences))
}
tty, err := webtty.New(&wsWrapper{conn}, slave, opts...)
if err != nil {
return errors.Wrapf(err, "failed to create webtty")
}
err = tty.Run(ctx)
return err
}
func (server *Server) handleIndex(w http.ResponseWriter, r *http.Request) {
titleVars := server.titleVariables(
[]string{"server", "master"},
map[string]map[string]interface{}{
"server": server.options.TitleVariables,
"master": map[string]interface{}{
"remote_addr": r.RemoteAddr,
},
},
)
titleBuf := new(bytes.Buffer)
err := server.titleTemplate.Execute(titleBuf, titleVars)
if err != nil {
http.Error(w, "Internal Server Error", 500)
return
}
indexVars := map[string]interface{}{
"title": titleBuf.String(),
}
indexBuf := new(bytes.Buffer)
err = server.indexTemplate.Execute(indexBuf, indexVars)
if err != nil {
http.Error(w, "Internal Server Error", 500)
return
}
w.Write(indexBuf.Bytes())
}
func (server *Server) handleAuthToken(w http.ResponseWriter, r *http.Request) {
w.Header().Set("Content-Type", "application/javascript")
// @TODO hashing?
w.Write([]byte("var gotty_auth_token = '" + server.options.Credential + "';"))
}
func (server *Server) handleConfig(w http.ResponseWriter, r *http.Request) {
w.Header().Set("Content-Type", "application/javascript")
w.Write([]byte("var gotty_term = '" + server.options.Term + "';"))
}
// titleVariables merges maps in a specified order.
// varUnits are name-keyed maps, whose names will be iterated using order.
func (server *Server) titleVariables(order []string, varUnits map[string]map[string]interface{}) map[string]interface{} {
titleVars := map[string]interface{}{}
for _, name := range order {
vars, ok := varUnits[name]
if !ok {
panic("title variable name error")
}
for key, val := range vars {
titleVars[key] = val
}
}
// safe net for conflicted keys
for _, name := range order {
titleVars[name] = varUnits[name]
}
return titleVars
}