web から、cron の設定をする #PHP

Web 経由で、cron の設定をする方法です。
Ubuntu 17.04 の　Nginx で確認しました。
php7.0-ssh2 をインストールする必要があります。

<!DOCTYPE html>
<html lang="ja">
<head>
<meta http-equiv="Pragma" content="no-cache" />
<meta http-equiv="Cache-Control" content="no-cache" />
<meta http-equiv="CONTENT-TYPE" content="text/html; charset=utf-8" />
<script src="/js/jquery-3.2.1.min.js"></script>
<script src="cron_edit.js"></script>
<link href="cron_edit.css" rel="stylesheet">
<title>Cron Edit</title>
</head>
<body>
<h1>Cron Edit</h1>
<textarea name="text" id="text"></textarea>
<br />
<button id="submit">Submit</button>
<br />
<hr />
<div id="outarea_aa">outarea_aa</div>
<div id="outarea_bb">outarea_bb</div>
<div id="outarea_cc">outarea_cc</div>
<div id="outarea_dd">outarea_dd</div>
<div id="outarea_ee">outarea_ee</div>
<div id="outarea_ff">outarea_ff</div>
<div id="outarea_gg">outarea_gg</div>
<div id="outarea_hh">outarea_hh</div>
<hr />
Version: Jul/31/2017<p />
</body>
</html>

cron_edit.css

/* -------------------------------------------------------------- */
/*
        cron_edit.css

                    Jul/31/2017
*/
/* -------------------------------------------------------------- */
#text {
    width:640px;
    height:400px;
}

button#submit {
    width:200px;
    height:30px;
}

/* -------------------------------------------------------------- */

cron_edit.js

// -----------------------------------------------------------------------
//  cron_edit.js
//
//                  Jul/29/2017
//
// -----------------------------------------------------------------------
jQuery (function ()
{
    jQuery("#outarea_aa").text ("*** cron_edit.js *** 開始 ***")

    const url_php = "cron_fetch.php"

    jQuery.get (url_php,function (data_rec)
        {
        jQuery("#text").text (data_rec)

        submit_click_monitor ()
        })

    jQuery("#outarea_hh").text ("*** cron_edit.js *** 終了 ***")
})

// -----------------------------------------------------------------------
function submit_click_monitor ()
{
    jQuery("button#submit").click (function ()
        {
        jQuery("#outarea_bb").text ("*** clicked ***")

        const text_in = jQuery("#text").val ()

        const url_php = "cron_update.php"

        const args={"text": text_in}

        jQuery.post (url_php,args,function (data_rec)
            {
            jQuery("#outarea_ff").html (data_rec)
            })
        })
}

// -----------------------------------------------------------------------

cron_config.php

<?php
// ----------------------------------------------------------------
//
//  cron_config.php
//
//                      Jul/31/2017
//
// ----------------------------------------------------------------
date_default_timezone_set('Asia/Tokyo');
//
$host = "127.0.0.1";
$user = "scott";
$password = "tiger";

// ----------------------------------------------------------------
?>

cron_fetch.php

<?php
// ----------------------------------------------------------------
//
//  cron_fetch.php
//
//                      Jul/31/2017
//
// ----------------------------------------------------------------
include "cron_config.php";

$connection = ssh2_connect($host, 22);

if($connection !== false){
    $auth = ssh2_auth_password($connection, $user, $password);
    ssh2_exec($connection, "crontab -l > /tmp/cron.txt");
    $stream = ssh2_exec($connection, "cat /tmp/cron.txt");
    stream_set_blocking($stream, true);
    echo stream_get_contents($stream);
//  ssh2_exec($connection, "exit");
}


// echo "*** cron_fetch.php *** end ***\n";
// ----------------------------------------------------------------
?>

cron_update.php

<?php
// ----------------------------------------------------------------
//
//  cron_update.php
//
//                      Jul/31/2017
//
// ----------------------------------------------------------------
include "cron_config.php";
// ----------------------------------------------------------------
function file_write_proc ($string_out,$file_out)
{
    $fp_out=fopen ($file_out,"w");
    flock ($fp_out,LOCK_EX);
    fputs ($fp_out,$string_out);
    flock ($fp_out,LOCK_UN);
    fclose ($fp_out);

    chmod ($file_out,0666);
}

// ----------------------------------------------------------------

$file_out = "/tmp/cron_sent.txt";

if (isset ($_REQUEST['text']))
    {
    $string_out = $_REQUEST['text'];
//  echo $string_out;

    file_write_proc ($string_out,$file_out);
    }

$connection = ssh2_connect($host, 22);

if($connection !== false){
    $auth = ssh2_auth_password($connection, $user, $password);

    $file_received = "/tmp/cron_received.txt";
    $result = ssh2_scp_send ($connection,$file_out,$file_received);

    echo "result = " . $result . "<br />";

    $command =  "crontab < " . $file_received;
    echo $command . "<br />";
    $result = ssh2_exec($connection, $command);
    echo "result = " . $result . "<br />";

    }

echo "*** cron_edit.php *** end ***\n";
// ----------------------------------------------------------------
?>