rector/docs/HowToCreateOwnRector.md

4 Steps Create Own Rector

First, make sure your needs is not covered by any existing Rectors.

Let's say you want to prefix private method call names starting with "internal" with _. Not very practical, but it will show the Rector flow.

1. New Class

Create class that extends Rector\Rector\AbstractRector. It has many useful methods for checking node type, name, add nodes or remove one. Just run $this-> and let PHPStorm show you all possible methods.

There 3 methods to implement:

<?php declare(strict_types=1);

namespace App\Rector;

use PhpParser\Node;
use Rector\Rector\AbstractRector;
use Rector\RectorDefinition\RectorDefinition;

final class MyFirstRector extends AbstractRector
{
    public function getDefinition(): RectorDefinition
    {
        // what does this do?
        // minimalistic before/after sample - to explain in code
    }

    /**
     * @return string[]
     */
    public function getNodeTypes(): array
    {
        // what node types we look for?
        // String_? FuncCall?
        // pick any from https://github.com/nikic/PHP-Parser/tree/master/lib/PhpParser/Node
        return [];
    }

    public function refactor(Node $node): ?Node
    {
        // what will happen with the node?
        // common work flow:
        // - should skip? → return null;
        // - modify it? → do it, then return $node;
        // - remove/add nodes elsewhere? → do it, then return null;
    }
}

2. Add Methods

<?php declare(strict_types=1);

namespace App\Rector;

use PhpParser\Node;
use PhpParser\Node\Identifier;
use PhpParser\Node\Expr\MethodCall;
use Rector\Rector\AbstractRector;
use Rector\RectorDefinition\CodeSample;
use Rector\RectorDefinition\RectorDefinition;

final class MyFirstRector extends AbstractRector
{
    public function getDefinition(): RectorDefinition
    {
        return new RectorDefinition('Add "_" to private method calls that start with "internal"', [
            new CodeSample('$this->internalMethod();', '$this->_internalMethod();')
        ]);
    }

    /**
     * @return string[]
     */
    public function getNodeTypes(): array
    {
        return [MethodCall::class];
    }

    /**
     * @param MethodCall $node - we can add "MethodCall" type here, because only this node is in "getNodeTypes()"
     */
    public function refactor(Node $node): ?Node
    {
        // we only care about "internal*" method names
        if (! $this->nameStartsWith($node, 'internal')) {
            return null;
        }

        $node->name = new Identifier('_' . $this->getName($node));

        return $node;
    }
}

3. Register it rector.yml

 services:
+    App\Rector\MyFirstRector: ~

4. Let Rector Refactor Your Code

vendor/bin/rector process src --dry-run

# apply it
vendor/bin/rector process src

If you use rector.yml from another directory or another name, set it with --config option:

vendor/bin/rector process src --config ../custom-rector.yml

That's it!