tivie/command

An utility library that harmonizes OS differences and executes external programs in a safer way

Command

, _(*1)

A cross-platform PHP utility library that harmonizes OS differences and executes external programs in a safer way, _(*2)

Introduction

Command is a small lightweight utility library that enables you to run external programs or commands in a safer way. It also harmonizes the differences between Windows and Unix environments, removing the need to create specific code for each platform., _(*3)

Features

• Platform independent: run the same code in Unix and Windows
• Fixes issues with proc_open in windows environment
• Object Oriented command builder with fluent interface
• Argument escaping, for safer command calls
• Command chaining with support for conditional calls and piping in both Windows and Unix environment

Installation

You can install it by cloning the git repository or using composer., _(*4)

Git clone

git clone https://github.com/tivie/command.git

Composer

Add these lines to your composer.json:, _(*5)

    {
        "require": {
            "tivie/command": "*"
        }
    }

or run the following command:, _(*6)

php composer.phar require tivie/command

Quick Usage guide

Simple example

Let's say we want to 'ping' google.com 3 times with 32bytes packets. With PHP we could do something like this:, _(*7)

exec("ping -c 3 -s 24 www.google.com", $otp, $ec);

We want, however, to make our command a little bit safer and escape our arguments., _(*8)

$host = 'www.google.com';
$c = 3;
$s = 24; //Linux adds 8 bytes of ICMP header data
$cmd = sprintf("ping -c %d -s %d %s", escapeshellarg($c), escapeshellarg($s), escapeshellarg($host));
exec($cmd, $otp, $ec);

This will work as expected in a GNU/Linux environment but will fail on Windows, since '-c' is an unrecognized flag and '-s' means something entirely different. The windows version would be :, _(*9)

$host = 'www.google.com';
$c = 3;
$s = 32;
$cmd = sprintf("ping -n %d -l %d %s", escapeshellarg($c), escapeshellarg($s), escapeshellarg($host));
exec($cmd, $otp, $ec);

If we want to ensure cross platform compatibility we will need to perform some kind of OS check and run the appropriate command based on that check:, _(*10)

$host = 'www.google.com';
$c = 3;
if (PHP_OS === 'WINDOWS' || PHP_OS === 'WIN32' || PHP_OS === 'WINNT' /* And a few more*/ ) {
    $s = 32;
    $cmd = sprintf("ping -n %d -l %d %s", escapeshellarg($c), escapeshellarg($s), escapeshellarg($host));
} else {
    $s = 24; //Linux adds 8 bytes of ICMP header data
    $cmd = sprintf("ping -c %d -s %d %s", escapeshellarg($c), escapeshellarg($s), escapeshellarg($host));
}
exec($cmd, $otp, $ec);

While this works in most cases, with more complex commands (or command chains) you would be forced to repeat yourself a lot, with a lot of conditional checks., _(*11)

With command library, you don't need to: it will do this work for you., _(*12)

$cmd = new \Tivie\Command\Command(\Tivie\Command\ESCAPE);
$cmd->setCommand('ping')
    ->addArgument(
        new Argument('-n', 3, \Tivie\OS\WINDOWS_FAMILY)
    )
    ->addArgument(
        new Argument('-l', 32, \Tivie\OS\WINDOWS_FAMILY)
    )
    ->addArgument(
        new Argument('-c', 3, \Tivie\OS\UNIX_FAMILY)
    )
    ->addArgument(
        new Argument('-s', 24, \Tivie\OS\UNIX_FAMILY)
    )
    ->addArgument(
        new Argument('www.google.com')
    );

$result = $cmd->run();

Command::run() returns a Result object that you can access to retrieve the result of the command., _(*13)

echo $result->getStdOut();    // The Standard Output of the command
echo $result->getLastLine();  // The last line of the Standard Output
echo $result->getStdIn();     // The passed standard input
echo $result->getStdErr();    // The standard error
echo $result->getExitCode();  // The command's exit code

Chaining commands

Command library supports command chaining, _(*14)

$cmd1 = new \Tivie\Command\Command();
$cmd1->setCommand('php')
    ->addArgument(new Argument('-v'));

$cmd2 = new \Tivie\Command\Command();
$cmd2->setCommand('echo')
    ->addArgument(new Argument('foo'));

$results = $cmd1->chain()
                ->add($cmd2)
                /* any number of commands here */
                ->run(); 

$results will be an array of Result objects., _(*15)

You can also specify chaining conditions, similar to Linux's Chaining Operators., _(*16)

RUN_REGARDLESS (';')

$cmd1->chain()->add($cmd2, \Tivie\Command\RUN_REGARDLESS)->run(); 

$cmd2 will be run regardless of the exitcode of $cmd1. Mimics the ';' chaining operator and is the default action., _(*17)

RUN_IF_PREVIOUS_SUCCEEDS ('&&')

$cmd1->chain()->add($cmd2, \Tivie\Command\RUN_IF_PREVIOUS_SUCCEEDS)->run(); 

$cmd2 will only be run if $cmd1 is successful, that is, if it exits with exitcode 0. Mimics the '&&' chaining operator., _(*18)

RUN_IF_PREVIOUS_FAILS ('||')

$cmd1->chain()->add($cmd2, \Tivie\Command\RUN_IF_PREVIOUS_FAILS)->run(); 

$cmd2 will only be run if $cmd1 is not successful, that is, if it exits with exitcode different than 0. Mimics the '||' chaining operator., _(*19)

Complex command chains

That being said, you can create complex command chains. For instance:, _(*20)

$cmd1->chain()
     ->add($cmd2, \Tivie\Command\RUN_IF_PREVIOUS_SUCCEEDS)
     ->add($cmd3, \Tivie\Command\RUN_IF_PREVIOUS_FAILS)
     ->add($cmd4, \Tivie\Command\RUN_REGARDLESS)
     ->run(); 

This will: 1. Run $cmd1 2. If $cmd1 is successful then runs $cmd2 3. If $cmd1 or $cmd2 fails it will run $cmd3 4. Finally will run $cmd4, _(*21)

Piping

Command library supports 2 types of piping: - STDOUT->STDIN - STDOUT->Argument, _(*22)

STDOUT to STDIN

Piping the standard output of one command to the next's standard input is easy. You just need to set the third argument of Chain::add() to true., _(*23)

$cmd1->chain()->add($cmd2, \Tivie\Command\RUN_REGARDLESS, true)

STDOUT to Arguments

You can also pass the STDOUT of previous command as an argument of the next command. The library will look for the special keyword (placeholder) '!PIPE!' in the command's argument key and values and replace them with the previous command's STDOUT. You will then need to pass true as the third argument in Chain::add() function, same as the above case., _(*24)

$cmd2->addArgument(new Argument('foo'), \Tivie\Command\PIPE_PH); // PIPE_PH = '!PIPE!'
$cmd1->chain()->add($cmd2, \Tivie\Command\RUN_REGARDLESS, true);

Add support for other OS

IF you need to more specific OS checks, you can extend Detector class or create a new class that implements DetectorInterface. For further information, please read the [php-os-detector][5] documentation., _(*25)

Example:, _(*26)

const OS_2_WARP  = 65540; //65536 + 4

class MyOSDetector extends \Tivie\OS\Detector
{
    public function detect()
    {
        $os = parent::detect();

        switch($os->name) {
            case "OS/2":
            case "OS/2 WARP":
                $os->family = \Tivie\Command\OS\OTHER_FAMILY;
                $os->def = OS_2_WARP;
                break;
        }

        return $os;
    }
}

You don't need to create a new constant pertaining the new OS (you can use one of the pre existing families). If, however, you choose to do so, the new OS const value should be a unique number in the 2^n sequence plus the family the OS belongs to. In the example we chose 16th term (65536) plus the OS family (in this case, FAMILY_OTHER) which is 4., _(*27)

Contribute

Feel free to contribute by forking or making suggestions., _(*28)

Issue tracker: https://github.com/tivie/command/issues, _(*29)

Source code: https://github.com/tivie/command, _(*30)

Contributors

Tivie Sophie-OS, _(*31)

License

Command Library is released under Apache 2.0 license. For more information, please consult the LICENSE file in this repository or http://www.apache.org/licenses/LICENSE-2.0.txt., _(*32)