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|
/*
* WebSocket endpoint handler
*
* 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 (
"errors"
"log"
"net/http"
"time"
"github.com/coder/websocket"
"github.com/google/uuid"
"github.com/jackc/pgx/v5"
)
/*
* Handle requests to the WebSocket endpoint and establish a connection.
* Authentication is handled here, but afterwards, the connection is really
* handled in handleConn.
*/
func handleWs(w http.ResponseWriter, req *http.Request) {
wsOptions := &websocket.AcceptOptions{
Subprotocols: []string{"cca1"},
} //exhaustruct:ignore
c, err := websocket.Accept(
w,
req,
wsOptions,
)
if err != nil {
wstr(
w,
http.StatusBadRequest,
"This endpoint only supports valid WebSocket connections.",
)
return
}
defer func() {
_ = c.CloseNow()
}()
fake := false
sessionCookie, err := req.Cookie("session")
if errors.Is(err, http.ErrNoCookie) {
if config.Auth.Fake == 0 {
err := writeText(req.Context(), c, "U")
if err != nil {
log.Println(err)
}
return
}
fake = true
} else if err != nil {
err := writeText(req.Context(), c, "E :Error fetching cookie")
if err != nil {
log.Println(err)
}
return
}
var userID string
var session string
var expr int
if fake {
switch config.Auth.Fake {
case 9080:
_uuid, err := uuid.NewRandom()
if err != nil {
log.Println(err)
return
}
userID = _uuid.String()
case 4712:
userID = "fake"
default:
panic("not supposed to happen")
}
session, err = randomString(20)
if err != nil {
log.Println(err)
return
}
_, err = db.Exec(
req.Context(),
"INSERT INTO users (id, name, email, department, session, expr) VALUES ($1, $2, $3, $4, $5, $6)",
userID,
"Fake User",
"fake@runxiyu.org",
"Y11",
session,
time.Now().Add(
time.Duration(config.Auth.Expr)*time.Second,
).Unix(),
)
if err != nil && config.Auth.Fake != 4712 {
/* TODO check pgerr */
err := writeText(
req.Context(),
c,
"E :Database error while writing fake account info",
)
if err != nil {
log.Println(err)
}
return
}
err = writeText(req.Context(), c, "FAKE "+userID+" "+session)
if err != nil {
log.Println(err)
return
}
} else {
session = sessionCookie.Value
err = db.QueryRow(
req.Context(),
"SELECT id, expr FROM users WHERE session = $1",
session,
).Scan(&userID, &expr)
if errors.Is(err, pgx.ErrNoRows) {
err := writeText(req.Context(), c, "U")
if err != nil {
log.Println(err)
}
return
} else if err != nil {
err := writeText(
req.Context(),
c,
"E :Database error while selecting session",
)
if err != nil {
log.Println(err)
}
return
}
}
/*
* Now that we have an authenticated request, this WebSocket connection
* may be simply associated with the session and userID.
* TODO: There are various race conditions that could occur if one user
* creates multiple connections, with the same or different session
* cookies. The last situation could occur in normal use when a user
* opens multiple instances of the page in one browser, and is not
* unique to custom clients or malicious users. Some effort must be
* taken to ensure that each user may only have one connection at a
* time.
*/
err = handleConn(
req.Context(),
c,
session,
userID,
)
if err != nil {
log.Printf("%v", err)
return
}
}
|
