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/*
* Utility functions
*
* 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 (
"crypto/rand"
"encoding/base64"
"errors"
"fmt"
"log"
"net/http"
)
var errUnexpectedRace = errors.New("unexpected race condition")
/*
* Write a string to a http.ResponseWriter, setting the Content-Type and status
* code.
*/
func wstr(w http.ResponseWriter, code int, msg string) {
w.Header().Set("Content-Type", "text/plain; charset=utf-8")
w.WriteHeader(code)
_, err := w.Write([]byte(msg))
if err != nil {
log.Printf("Error wstr'ing to writer: %v", err)
}
}
/*
* Generate a random url-safe string.
* Note that the "sz" parameter specifies the number of bytes taken from the
* random source divided by three and does NOT represent the length of the
* encoded string. It's divided by three because we're using base64 and it's
* ideal to ensure that the entropy remains consistent throughout the string.
*/
func randomBytes(sz int) (string, error) {
r := make([]byte, 3*sz)
_, err := rand.Read(r)
if err != nil {
return "", fmt.Errorf("error generating random string: %w", err)
}
return base64.RawURLEncoding.EncodeToString(r), nil
}
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