How to call shell programs as functions with PHP


I’m a big fan of Symfony’s Process Component. I’ve used intensively this component within a project and I noticed that I needed a wrapper to avoid to write again and again the same code. Suddenly a cool python library came to my head: sh. With python’s sh we can call any program as if it were a function:

from sh import ifconfig
print(ifconfig("wlan0"))

Outputs:

wlan0   Link encap:Ethernet  HWaddr 00:00:00:00:00:00
        inet addr:192.168.1.100  Bcast:192.168.1.255  Mask:255.255.255.0
        inet6 addr: ffff::ffff:ffff:ffff:fff/64 Scope:Link
        UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
        RX packets:0 errors:0 dropped:0 overruns:0 frame:0
        TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
        collisions:0 txqueuelen:1000
        RX bytes:0 (0 GB)  TX bytes:0 (0 GB)

So I decided to develop something similar in PHP. This library is not exactly the same than python one. Python’s sh allows more cool things such as non-blocking processes, baking, … not available in my PHP one’s, but at least I can call shell programs as functions in a simple way (and that’s was my scope). Let’s start.

One simple example of Process:

use Symfony\Component\Process\Process;

$process = new Process('-latr ~');
$process->setTimeout(3600);
$process->run();

echo $process->getOutput();

With sh library we can do:

use Sh/Sh;

$sh  = new Sh();
echo $sh->ls('-latr ~');

You can check the source code in github, but it’s very simple one. Basically it’s a parser that creates the command line string, and another class that calls to the parser and sends the output to Process component. Whit the magic function __call we can use shell commands as functions.

The command’s arguments can be one string ‘-latr ~’ or one array ['-latr', '~']. You can see more example in the unit tests here

Symfony/Process also allows us to get feedback in real time:

use Symfony\Component\Process\Process;

$process = new Process('ls -lsa');
$process->run(function ($type, $buffer) {
    if ('err' === $type) {
        echo 'ERR > '.$buffer;
    } else {
        echo 'OUT > '.$buffer;
    }
});

Sh uses this feature, so we can do things like that:

$sh->tail('/var/log/messages', function ($buffer)  {
    echo $buffer;
});

We can see more examples here:

<?php
error_reporting(-1);
include __DIR__ . '/../vendor/autoload.php';
use Sh\Sh;

echo Sh::factory()->runCommnad('notify-send', ['-t', 5000, 'title', 'HOLA']);
$sh  = new Sh();
echo $sh->ifconfig("eth0");
echo $sh->ls('-latr ~');
echo $sh->ls(['-latr', '~']);
$sh->tail('-f /var/log/apache2/access.log', function ($buffer)  {
    echo $buffer;
});

As I said before the library is in github and also you can use with composer:

require: "gonzalo123/sh": "dev-master"

Updated!

Now Sh library supports chained arguments (baking)

// chainable commands (baking)
$sh->ssh(array('myserver.com', '-p' => 1393))->whoami();
// executes: ssh myserver.com -p 1393 whoami

$sh->ssh(array('myserver.com', '-p' => 1393))->tail(array("/var/log/dumb_daemon.log", 'n' => 100));
// executes: ssh myserver.com -p 1393 tail /var/log/dumb_daemon.log -n 100
});
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About Gonzalo Ayuso

Web Architect specialized in Open Source technologies. PHP, Python, JQuery, Dojo, PostgreSQL, CouchDB and node.js but always learning.

Posted on November 19, 2012, in php, Symfony2, Technology and tagged , . Bookmark the permalink. 4 Comments.

  1. Thanks for sharing! This info was included into a digest of the best PHP news and releases: http://www.zfort.com/blog/php-digest-december-4-2012/ Check it out, I bet this digest is going to be interesting for you!

  1. Pingback: How to call shell programs as functions with PHP ← Bookmarks

  2. Pingback: PHP Digest: Simplified Password Hashing, Creation of PHP Framework Using Symfony2 Components, Xdebug Tutorial and Much More | Zfort Group Blog

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