05-context.md

Context

For every command that castor run, it uses a Context object. This object contains the default values for the run or watch function (directory, environment variables, pty, tty, etc...).

It also contains custom values that can be set by the user and reused in commands.

The context is immutable, which means that every time you change a value, a new context is created.

Using the context

You can get the initial context thanks to the get_context() function:

use Castor\Attribute\AsTask;

use function Castor\get_context;
use function Castor\run;

#[AsTask]
function foo(): void
{
    $context = get_context();

    echo $context->currentDirectory; // will print the directory of the castor.php file

    $context = $context->withPath('/tmp'); // will create a new context where the current directory is /tmp
    run('pwd', context: $context); // will print "/tmp"
}

There is a variable() function to get a value stored in the Context:

use Castor\Attribute\AsTask;

use function Castor\get_context;
use function Castor\variable;

#[AsTask]
function foo(): void
{
    $foobar = variable('foobar', 'default value');

    // Same as:
    $context = get_context();
    try {
        $foobar = $context['foobar'];
    } catch (\OutOfBoundsException) {
        $foobar = 'default value;
    }
}

Creating a new context

You can create a new context by declaring a function with the Castor\Attribute\AsContext attribute:

use Castor\Attribute\AsContext;
use Castor\Context;

use function Castor\run;

#[AsContext]
function my_context(): Context
{
    return new Context(environment: ['FOO' => 'BAR']);
}

#[AsTask]
function foo(): void
{
    run('echo $FOO');
}

By default the foo command will not print anything as the FOO environment variable is not set. If you want to use your new context you can use the --context option:

$ php castor.phar foo

$ php castor.phar foo --context=my-context
BAR

Note You can override the context name by setting the name argument of the AsContext attribute.

Setting a default context

You may want to set a default context for all your commands. You can do that by setting the default argument to true in the AsContext attribute:

use Castor\Attribute\AsContext;
use Castor\Context;

use function Castor\run;

#[AsContext(default: true, name: 'my_context')]
function create_default_context(): Context
{
    return new Context(['foo' => 'bar'], currentDirectory: '/tmp');
}

#[AsTask]
function foo(Context $context): void
{
    run(['echo', $context['foo']]); // will print bar even if you do not use the --context option
    run('pwd'); // will print /tmp
}