Tarsana Command

A library to build command line applications using PHP. This is part of the Tarsana Project.

Table of Contents

• Installation

• Your First Command

• Initializing The Command

• Showing The Help And Version Of A Command

• Reading & Writing to The Console

• Defining Arguments and Options

• Reading Arguments and Options Interactively Since version 1.1.0

• Handeling The Filesystem

• Loading Configuration New on version 1.2.0

• Rendering Templates

• Adding SubCommands

• Testing Commands

• What's Next

• Development Notes

Installation

Install it using Composer

composer require tarsana/command

Your First Command

Let's write a "Hello World" command. Create a file hello.php with the following content:

<?php
require __DIR__.'/vendor/autoload.php';

use Tarsana\Command\Command;

class HelloWorld extends Command {

    protected function execute()
    {
        $this->console->line('Hello World');
    }

}

(new HelloWorld)->run();

Then run it from the terminal:

$ php hello.php
Hello World

Congratulations, you have just written your first command :D

As you see, Tarsana\Command\Command is a class providing the basic features of a command. Every command should extend it and implement the execute() method.

Initializing The Command

In addition, Command gives the init() method which is used the initialize the command general attributes. Let's rewrite our HelloWorld command:

class HelloWorld extends Command {

	protected function init ()
	{
		$this->name('Hello World')
		     ->version('1.0.0-alpha')
		     ->description('Shows a "Hello World" message');
	}

    protected function execute()
    {
        $this->console->line('Hello World');
    }

}

Here we are overriding the init() method to define the command name, version and description.

Note that the setter of an attribute foo is named foo() instead of setFoo(). I know that this is not a common convention but it makes sense for me. :P

$this->name('blabla'); // will set the name to 'blabla' and return $this
$this->name(); // calling it without parameter will get the value of name

Showing the Help and Version of a Command

To show the version of a command, we use the --version flag (we will learn after that this is actually a sub command). We also have the --help to show the help message:

Reading & Writing to the Console

The attribute console is used to handle the reading and writing operations to the console.

Let's update our command to read the user name:

protected function execute()
{
    $this->console->out('Your name: ');
    $name = $this->console->readLine();
    $this->console->line("Hello {$name}");
}

$ php hello.php
Your name: Amine
Hello Amine

• The readLine() method reads a line from the stdin and returns it as string.
• The out() method writes some text to stdout (without a line break).
• The line() method writes some text to stdout and adds a line break.
• The error() method writes some text to stderr and adds a line break.

The Console class provides some tags to control the output:

$this->console->line('<background:15><color:19>Blue text on white background<reset>');
$this->console->line('<background:124><color:15>White text on red background<reset>');

The <background:$number> and <color:$number> tags allows to set the background and foreground colors of the text to be written; the <reset> tag resets the default values. The colors are given as numbers from the 256-color mode.

List of supported tags

• <color:$n>: Sets the foreground text to the color $n in 256-color mode.
• <background:$n>: Sets the foreground text to the color $n in 256-color mode.
• <reset>: Resets the formatting default values.
• <bold>: Makes the text bold.
• <underline>: Underlines the text.

Console allows you also to define styles using aliases:

$this->console->alias('<danger>', '<background:124><color:15><bold>');
$this->console->alias('</danger>', '<reset>');

$this->console->line('<danger>Some text</danger>');
// is equivalent to
$this->console->line('<background:124><color:15><bold>Some text<reset>');

Predefined aliases are:

$this->console->line('<info> information text </info>');
$this->console->line('<warn> warning text </warn>');
$this->console->line('<success> success text </success>');
$this->console->line('<error> error text </error>');
$this->console->line('<tab>'); // prints four spaces "    "
$this->console->line('<br>'); // prints line break  PHP_EOL

Note: tags and aliases can be used in all strings printed to the console, including the command and arguments descriptions.

Defining Arguments and Options

The command syntax is defined using the Syntax library. Let's start with a command that repeats a word a number of times:

class RepeatCommand extends Command {

    protected function init ()
    {
        $this->name('Repeat')
             ->version('1.0.0')
             ->description('Repeats a word a number of times')
             ->syntax('word: string, count: (number: 3)')
             ->options(['--upper'])
             ->describe('word', 'The word to repeat')
             ->describe('count', 'The number of times to repeat the word')
             ->describe('--upper', 'Converts the result to uppercase');
    }

    protected function execute()
    {
        $result = str_repeat($this->args->word, $this->args->count);
        if ($this->option('--upper'))
            $result = strtoupper($result);
        $this->console->line($result);
    }

}

We are using the method syntax() to define the syntax of arguments. The string given to this method follows the rules described here

The describe() method is used to describe an argument.

When you define the syntax of the command; arguments are parsed automatically and available in the execute() method via the args attribute.

The help subcommand shows full description of the arguments and options:

And the result is:

$ php repeat.php foo 5
foofoofoofoofoo
$ php repeat.php bar --upper
BARBARBAR

In the second example, the count argument takes automatically its default value.

Warning: Giving wrong arguments generates an error

Reading Arguments and Options Interactively

Some commands can have long and complicated list of arguments. Defining the syntax of such command is easy thanks to Syntax but typing the arguments in the command line becomes challenging.

Let's take the following command for example:

class ClassGenerator extends Command {
    protected function init()
    {
        $this->name('Class Generator')
        ->version('1.0.0')
        ->description('Generates basic code for a class.')
        ->syntax('
            language: string,
            name: string,
            parents: ([string]:[]),
            interfaces: ([string]:[]),
            attrs: [{
                name,
                type,
                hasGetter: (boolean:true),
                hasSetter: (boolean:true),
                isStatic: (boolean:false)
            }],
            methods: ([{
                name: string,
                type: string,
                args: [{ name, type, default: (string:null) |.}],
                isStatic: (boolean:false)
            }]:[])
        ')
        ->descriptions([
            'language'          => 'The programming language in which the code will be generated.',
            'name'              => 'The name of the class.',
            'parents'           => 'List of parent classes names.',
            'interfaces'        => 'List of implemented interfaces.',
            'attrs'             => 'List of attributes of the class.',
            'attrs.name'        => 'The name of the attribute.',
            'attrs.type'        => 'The type of the attribute.',
            'attrs.hasGetter'   => 'Generate a getter for the attribute.',
            'attrs.hasSetter'   => 'Generate a setter for the attribute.',
            'attrs.isStatic'    => 'The attribute is static.',
            'methods'           => 'List of methods of the class.',
            'methods.name'      => 'The method name.',
            'methods.type'      => 'The method return type.',
            'methods.args'      => 'List of arguments of the method.',
            'methods.isStatic'  => 'This method is static.'
        ]);
    }

    protected function execute()
    {
        $this->console->line("Generate code for the class {$this->args->name} in {$this->args->language}...");

    }
}

if you run the command using the -i flag, it will let you enter the arguments interactively:

After reading all args, the command will show the command line version of the entered args:

>  PHP User  Serializable name:string:true:true:false

which means that running

$ php class.php  PHP User  Serializable name:string:true:true:false

would produce the same result.

Handling The Filesystem

The fs attribute is an instance of Tarsana\IO\Filesystem that you can use to handle files and directories. Read the documentation for the full API.

By default, the Filesystem instance points to the directory from which the command is run. You can also initialize it to any directory you want:

using Tarsana\IO\Filesystem;
// ...
protected function init()
{
	$this->fs(new Filesystem('path/to/directory/you/want'));
}

Loading Configuration

In addition to the command line arguments, the user can provide data to your command via configuration files. This is useful because it lets you define a default configuration file and lets the user change some values with a custom configuration file.

Let's write an example command which have a global configuration file at /home/user/.config.json. It lets the user customize value via the file config.json in the current directory:

class ConfigCommand extends Command {
    protected function init()
    {
        // ...
        $this->configPaths(['/home/user/.config.json', 'config.json']);
    }

    protected function execute()
    {
        // getting a config value
        // assuming that $data is the merged content of the config files
        $this->config('name'); // returns $data['name']
        $this->config('foo.bar.baz'); // returns $data['foo']['bar']['baz']
        $this->config(); // returns $data
    }
}

• The method configPaths take a list of paths, loads them and merges them into one configuration (it use array_replace_recursive internally).

• The method config is used to retreive configuration values.

Note that:

• Only json files are supported as configuration files for the moment. Please open an issue or make a Pull Request to add other formats.

• configPaths will silently ignore paths which does not exist in the filesystem.

• A subcommand will always have the same configuration data as its parent command, unless configPaths is used to override it.

Rendering Templates

The Command class gives also possibility to render templates. The default template engine is Twig but you can use your favorite one by implementing the interfaces TemplateLoaderInterface and TemplateInterface.

Let's make a command which renders a simple template. For this we will create two files:

render-hello.php
templates/
    hello.twig

hello.twig

Hello {{name}}

This is a simple template that print a hello message.

render-hello.php

<?php
require __DIR__.'vendor/autoload.php';

use Tarsana\Command\Command;
use Tarsana\Command\Templates\TwigTemplateLoader;


class RenderHelloCommand extends Command {

    protected function init ()
    {
        $this
            ->name('Renders Simple Template')
            ->description('Renders a simple twig template')
            ->syntax('name: (string:You)')
            ->describe('name', 'Your name')
            ->templatesPath(__DIR__.'/templates'); // defines the path to the templates
    }

    protected function execute()
    {
        $message = $this->template('hello')
            ->render([
                'name' => $this->args->name
            ]);

        $this->console->line($message);
    }

}

(new RenderHelloCommand)->run();

Result

$ php render-hello.php Foo
Hello Foo

$ php render-hello.php
Hello You

Adding SubCommands

You can add subcommands while initializing your command.

// ...
protected function init()
{
    //...
    // Assuming that FooCommand and BarCommand are already defined
    $this->command('foo', new FooCommand)
         ->command('bar', new BarCommand); // this erases the subcommand with key 'bar' if exists
    // Or set all subcommands at once (this will erase any previous subcommands)
    $this->commands([
        'foo' => new FooCommand,
        'bar' => new BarCommand
    ]);

    // Later on you can get subcommands
    $this->commands(); // returns all the subcommands as key-value array
    $this->command('name'); // gets the subcommand with the given name
    // will throw an exception if the subcommand is missing
    $this->hasCommand('name'); // checks if a subcommand with the given name exists
}

Now when you run

$ php your-script.php foo other arguments here

The FooCommand will be run with other arguments here as arguments.

Note: subcommands will always have the attributes console, fs and templatesLoader pointing to the same objects as their parent, as long as you don't change them explicitly in the subcommand's code.

Testing Commands

The class Tarsana\Tester\CommandTestCase extends PHPUnit\Framework\TestCase and adds useful methods to test Tarsana Commands.

Testing the Input and Output

Let's write a test for our HelloWorld command above which reads the user name than shows the hello message.

use Tarsana\Tester\CommandTestCase;

class HelloWorldTest extends CommandTestCase {

    public function test_it_prints_hello()
    {
        $this->withStdin("Amine\n")
             ->command(new HelloWorld)
             ->prints("Your name:")
             ->prints("Hello Amine<br>");
    }

    public function test_it_shows_hello_world_version()
    {
        $this->command(new HelloWorld, ['--version'])
             ->printsExactly("<info>Hello World</info> version <info>1.0.0-alpha</info><br>");
    }

}

withStdin(string $content) : CommandTestCase;

Sets the content of the standard input of the command.

command(Command $c, array $args = []) : CommandTestCase;

Runs the command $c with the standard input and $args then stores its outputs for further assertions.

printsExactly(string $text) : CommandTestCase;
prints(string $text) : CommandTestCase;
printsError(string $text) : CommandTestCase;

• printsExactly asserts that the standard output of the command equals $text. Note that tags are not applied to allow testing them easily.

• prints asserts that the standard output of the command contains $text.

• printsError asserts that error output of the command contains $text.

Testing the Arguments and Options

Let's now test the RepeatCommand above.

class RepeatCommandTest extends CommandTestCase {

    public function test_it_repeats_word_three_times()
    {
        $this->command(new RepeatCommand, ['foo'])
             ->argsEqual((object) [
                'word' => 'foo',
                'count' => 3
             ])
             ->optionsEqual([
                '--upper' => false
             ])
             ->printsExactly("foofoofoo<br>");
    }

    public function test_it_repeats_word_n_times_uppercase()
    {
        $this->command(new RepeatCommand, ['bar', '5', '--upper'])
             ->argsEqual((object) [
               'word' => 'bar',
               'count' => 5
             ])
             ->optionsEqual([
               '--upper' => true
             ])
             ->printsExactly("BARBARBARBARBAR<br>");
    }
}

argsEqual(object $args) : CommandTestCase;
optionsEqual(array $options) : CommandTestCase;

Assert that the parsed arguments and options of the command are equal to the given values.

Testing the Filesystem

Let's take the following command:

class ListCommand extends Command {

    protected function init ()
    {
        $this->name('List')
             ->version('1.0.0-alpha')
             ->description('Lists files and directories in the current directory.');
    }

    protected function execute()
    {
        foreach($this->fs->find('*')->asArray() as $file) {
            $this->console->line($file->name());
        }
    }

}

The test can be written as follows:

class ListCommandTest extends CommandTestCase {

    public function test_it_lists_files_and_directories()
    {
        $this->havingFile('demo.txt', 'Some text here!')
             ->havingFile('doc.pdf')
             ->havingDir('src')
             ->command(new ListCommand)
             ->printsExactly('demo.txt<br>doc.pdf<br>src<br>');
    }

    public function test_it_prints_nothing_when_no_files()
    {
        $this->command(new ListCommand)
             ->printsExactly('');
    }
}

havingFile(string $path, string $content = '') : CommandTestCase;
havingDir(string $path) : CommandTestCase;

The CommandTestCase run the command with a virtual filesystem. The methods havingFile and havingDir can be used to create files and directories on that filesystem before running the command.

What's Next

Please take a look at the examples in the examples directory, and try using the library to build some awesome commands. Any feedback is welcome!

Development Notes

• Version 2.0.0 Tarsana Command now uses PHPUnit 9 and thus requires PHP 7.3 or PHP 7.4.

• Version 1.2.1 The CommandTestCase is now an abstract class to avoid PHPUnit warnings.

• Version 1.2.0 Commands can now load configuration from multiple JSON files.

• Version 1.1.1 Fixed a bug with subcommands not having the default --help, --version and -i subcommands.

• Version 1.1.0 The flag -i added to commands to enable interactive reading of arguments and options.

• Version 1.0.1 Fixed a bug of subcommands having different instances of fs and templatesLoader from their parent.

• Version 1.0.0 The first version is finally out; have fun!