CallableInvoker

A lightweight PHP callable invoker with smart parameter resolution and execution decoration.

Overview

Frameworks often need to execute user-defined callables — controllers, message handlers, console commands, event listeners, or custom entry points — where the arguments are not known at compile time. Each of these requires the same boilerplate: inspect the callable's parameters, resolve their values from some runtime context, and optionally wrap the execution with cross-cutting behavior.

CallableInvoker extracts this pattern into a single reusable component. Instead of duplicating parameter resolution and decoration logic across your framework or application, you delegate it to the invoker and focus on what each callable actually does.

Installation

$ composer require open-solid/callable-invoker

Usage

The callable invoker accepts any PHP callable — closures, invokable objects, static methods, etc. — and handles the full execution lifecycle:

1. Resolve parameters automatically from a context array, default values, or nullability
2. Decorate the callable with optional layers (logging, validation, caching, etc.)
3. Execute with the resolved arguments and return the result

use OpenSolid\CallableInvoker\CallableInvoker;

class HelloHandler
{
    public function __invoke(string $name, int $age = 30): string
    {
        return "Hello, $name! You are $age years old.";
    }
}

$handler = new HelloHandler();
$invoker = new CallableInvoker();
$result = $invoker->invoke(callable: $handler, context: ['name' => 'Alice']);

echo $result; // Output: Hello, Alice! You are 30 years old.

Documentation

• Automatic Parameter Resolution: Resolves callable parameters from a provided context array, default values, and nullability.
• Execution Decoration: Wraps callables with nested decorators for cross-cutting concerns like logging, validation, caching, or timing. Each decorator can intercept, modify, or short-circuit the execution.
• Grouping: Organizes decorators and resolvers into named groups, allowing different callables to use different sets of decorators and resolvers. Multiple groups can be combined in a single invocation.
• Priority Ordering: Controls the execution order of decorators and resolvers via priority values, ensuring predictable behavior when multiple are registered.
• Support for Any Callable: Works with closures, invokable objects, static methods, named functions, and more.
• Extensibility: Register custom parameter value resolvers (ParameterValueResolverInterface) and decorators (CallableDecoratorInterface) to extend the invoker's behavior.
• Symfony Integration: Ships as a Symfony bundle with autoconfiguration via interfaces and PHP attributes (#[AsCallableDecorator], #[AsParameterValueResolver]), service tagging, and compiler passes.
• Error Handling: Provides specific exceptions for untyped parameters, variadic parameters, unsupported callables, and unresolvable parameters.