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
|
/*
* Handle the unified global state
*
* Copyright (C) 2024 Runxi Yu <https://runxiyu.org>
* SPDX-License-Identifier: AGPL-3.0-or-later
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU Affero General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Affero General Public License for more details.
*
* You should have received a copy of the GNU Affero General Public License
* along with this program. If not, see <https://www.gnu.org/licenses/>.
*/
package main
import (
"context"
"errors"
"fmt"
"net/http"
"strconv"
"sync/atomic"
"github.com/jackc/pgx/v5"
)
/*
* 0: Student access is disabled
* 1: Student have read-only access
* 2: Student can choose courses
*/
var state uint32 /* atomic */
func loadState() error {
var _state uint32
err := db.QueryRow(
context.Background(),
"SELECT value FROM misc WHERE key = 'state'",
).Scan(&_state)
if err != nil {
if errors.Is(err, pgx.ErrNoRows) {
_state = 0
_, err := db.Exec(
context.Background(),
"INSERT INTO misc(key, value) VALUES ('state', $1)",
_state,
)
if err != nil {
return fmt.Errorf("%w: %w", errUnexpectedDBError, err)
}
} else {
return fmt.Errorf("%w: %w", errUnexpectedDBError, err)
}
}
atomic.StoreUint32(&state, _state)
return nil
}
func saveStateValue(ctx context.Context, newState uint32) error {
_, err := db.Exec(
ctx,
"UPDATE misc SET value = $1 WHERE key = 'state'",
newState,
)
if err != nil {
return fmt.Errorf("%w: %w", errUnexpectedDBError, err)
}
return nil
}
func setState(ctx context.Context, newState uint32) error {
switch newState {
case 0:
cancelPool.Range(func(_, value interface{}) bool {
cancel, ok := value.(*context.CancelFunc)
if !ok {
panic("chanPool has non-\"*contect.CancelFunc\" values")
}
(*cancel)()
return false
})
case 1:
propagate("STOP")
case 2:
propagate("START")
default:
return errInvalidState
}
err := saveStateValue(ctx, newState)
if err != nil {
return err
}
atomic.StoreUint32(&state, newState)
return nil
}
func handleState(w http.ResponseWriter, req *http.Request) {
sessionCookie, err := req.Cookie("session")
if errors.Is(err, http.ErrNoCookie) {
wstr(
w,
http.StatusUnauthorized,
"No session cookie, which is required for this endpoint",
)
return
} else if err != nil {
wstr(w, http.StatusBadRequest, "Error: Unable to check cookie.")
return
}
var userID, userName, userDepartment string
err = db.QueryRow(
req.Context(),
"SELECT id, name, department FROM users WHERE session = $1",
sessionCookie.Value,
).Scan(&userID, &userName, &userDepartment)
if err != nil {
if errors.Is(err, pgx.ErrNoRows) {
wstr(
w,
http.StatusForbidden,
"Invalid session cookie",
)
return
}
wstr(
w,
http.StatusInternalServerError,
fmt.Sprintf(
"Error: Unexpected database error: %s",
err,
),
)
return
}
if userDepartment != staffDepartment {
wstr(
w,
http.StatusForbidden,
"You are not authorized to view this page",
)
return
}
basePath := req.PathValue("s")
newState, err := strconv.ParseUint(basePath, 10, 32)
if err != nil {
wstr(
w,
http.StatusBadRequest,
"State must be an unsigned 32-bit integer",
)
return
}
err = setState(req.Context(), uint32(newState))
if err != nil {
wstr(
w,
http.StatusInternalServerError,
"Failed setting state, please return to previous page; are you sure it's within limits?",
)
return
}
http.Redirect(w, req, "/", http.StatusSeeOther)
}
|
