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/*
* Utility functions
*
* Copyright (C) 2024 Runxi Yu <https://runxiyu.org>
* SPDX-License-Identifier: BSD-2-Clause
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are
* met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
*
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS "AS IS" AND ANY
* EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR
* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
* PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
* LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
* NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
package main
import (
"crypto/rand"
"encoding/base64"
"fmt"
"log"
"net/http"
)
/*
* 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 random(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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