Aura CLI

The Aura CLI package provides a system for creating and executing CLI command objects. It includes facilities for parsing command-line options and handling standard input/output.

This package is compliant with PSR-0, PSR-1, and PSR-2. If you notice compliance oversights, please send a patch via pull request.

Basic Usage

(N.b.: The CLI package is one of the most complex packages in the Aura project.)

Instantiation and Execution

Most Aura packages allow you to instantiate an object by including a particular file. This is not the case with Aura CLI. Because commands are so specific to the logic of your particular needs, you will have to extend the AbstractCommand class yourself and add an action method for your own purposes.

First, either include the 'Aura.Cli/src.php' file to load the package classes, or add the 'Aura.Cli/src/' directory to your autoloader.

Next, create a command class of your own, extending the AbstractCommand class:

<?php
namespace Vendor\Package\Cli;
use Aura\Cli\AbstractCommand;
class ExampleCommand extends AbstractCommand
{
    public function action()
    {
        $this->stdio->outln('Hello World!');
    }
}

Instantiating and executing the command class is moderately complex; it needs several dependency objects, all provided by the Aura CLI package.

<?php
namespace Vendor\Package\Cli;
use Aura\Cli\Context;
use Aura\Cli\Getopt;
use Aura\Cli\OptionFactory;
use Aura\Cli\Stdio;
use Aura\Cli\Vt100;

// instantiate
$command = new ExampleCommand(
    new Context($GLOBALS),
    new Stdio(
        fopen('php://stdin', 'r'),
        fopen('php://stdout', 'w+'),
        fopen('php://stderr', 'w+'),
        new Vt100
    ),
    new Getopt(new OptionFactory)
);

// execute
$command->exec();

(If you have a dependency injection mechanism, you can automate the the creation and injection of the dependency objects. The Aura.Di package is one such system.)

Save the file as command.php, then invoke it like so:

php command.php

You should see a Hello World! message.

Action and Input/Output

The logic for the command goes in the action() method. In the example below, we perform some basic input/output.

<?php
namespace Vendor\Package;
use Aura\Cli\AbstractCommand;

class ExampleCommand extends AbstractCommand
{
    public function action()
    {
        $this->stdio->outln('Hello World!');
        $this->stdio->out('Please enter some text: ');
        $input = $this->stdio->in();
        $this->stdio->errln('Input was ' . $input);
    }
}

Use the $stdio object to work with standard input/output streams. Its methods are:

• outln() and out(): Print to stdout, with or without a line ending.

• errln() and err(): Print to stderr, with or without a line ending.

• inln() and in(): Read from stdin until the user hits enter; inln() leaves the trailing line ending in place, whereas in() strips it.

Method Hooks

There are four method hooks on the CLI command. Use the pre- and post-action methods to perform logic before and after the action; use pre- and post-exec methods to perform setup and teardown.

<?php
namespace Vendor\Package;
use Aura\Cli\AbstractCommand;

class ExampleCommand extends AbstractCommand
{
    protected $input = 'foo bar baz';
    
    public function preExec()
    {
        // perform object setup here
    }
    
    public function preAction()
    {
        $this->stdio->outln('The input is currently ' . $this->input);
    }
    
    public function action()
    {
        $this->stdio->out('Please enter some text: ');
        $this->input = $this->stdio->in();
    }
    
    public function postAction()
    {
        $this->stdio->outln('The input was %r%2' . $this->input . '%n');
    }
    
    public function postExec()
    {
        // perform object teardown here
    }
}

Notice in postAction() that we set the background and foreground text colors. For more information, please examine the Vt100 format codes.

Argument Params

We may wish to pass information as part of the invocation. To read this information while in the command, use $this->params.

<?php
namespace Vendor\Package;
use Aura\Cli\AbstractCommand;

class ExampleCommand extends AbstractCommand
{
    public function action()
    {
        foreach ($this->params as $key => $val) {
            $this->stdio->outln("Param $key is '$val'.");
        }
    }
}

For example, if we issue ...

$ php command.php foo bar baz

... then the action() will output:

Param 0 is 'command.php'
Param 1 is 'foo'.
Param 2 is 'bar'.
Param 3 is 'baz'.

Advanced Usage

Long And Short Options

In addition to argument params, we may wish to pass short or long options as part of the invocation. These are the -o and --option portions of the invocation.

To work with options, we first define them in the $options array of the command. Then we can retrieve the option values through the $getopt object.

To define an option, do something like the following:

<?php
namespace Vendor\Package;
use Aura\Cli\AbstractCommand;
use Aura\Cli\Option;

class ExampleCommand extends AbstractCommand
{
    protected $options = [
        'foo_bar' => [
            'long'    => 'foo-bar',
            'short'   => 'f',
            'param'   => Option::PARAM_REQUIRED,
            'multi'   => false,
            'default' => null,
        ],
    ];
    
    public function action()
    {
        $this->stdio->out("The value of -f/--foo-bar is ");
        $this->stdio->outln($this->getopt->foo_bar);
    }
}

When we invoke the above command like this ...

$ php command.php --foo-bar=gir

... it will print this output:

The value of -f/--foo-bar is gir.

The $options array is keyed on what we want as the option name, and each element is an array of option definition keys:

• 'long': The long form of the option, which is passed by prefixing it with two dashes at the command line. A long-form param value is passed by following it with an equals sign and the value; e.g., --foo-bar=some_value. Leave this empty if we do not want a long-form option.

• 'short': The short form of the option, which is passed by prefixing it with one dash at the command line. A short-form param value is passed by following it with a space and the value; e.g., -f some_value. Leave this empty if we do not want a short-form option.

• 'param': Is a a param value required for the option, is it optional, or is it disallowed? Use Option::PARAM_REQUIRED to force a param value to be passed, Option::PARAM_OPTIONAL to allow a value to be passed or not, or Option::PARAM_REJECTED to disallow any value from being passed.

• 'multi': Is the option allowed to be passed multiple times in the same command? E.g., "-f foo -f bar -f zim" will make the option value an array with three entries: ['foo', 'bar', 'zim'].

• 'default': The default value for the option if it is not passed.

After we have defined the options and passed them at the command line, we can read them from the $getopt object as magic read-only properties. Thus, for the above option named as 'foo_bar', we can retrieve its value by using $this->getopt->foo_bar.