PHP AOP

PHP AOP is a PHP library that provides a powerful Aspect Oriented Programming (AOP) implementation for PHP.

Installation

Usage

📖 List of contents

• Terminology
• Implicit Aspects
  • Create a Kernel
  • Create an Aspect
  • Target Classes
  • Initialize the Kernel
  • Result
• Class-Level Explicit Aspects
  • Create an Aspect
  • Target Classes
  • Initialize the Kernel
  • Result
• Method-Level Explicit Aspects
  • Create an Aspect
  • Target Classes
  • Initialize the Kernel
  • Result
• Features
• Limitations
• How it works
• Testing
• Contributing

Terminology

• AOP: Aspect Oriented Programming - A programming paradigm that aims to increase modularity by allowing the separation of cross-cutting concerns.

• Aspect: A class that implements the logic that you want to apply to your target classes. Aspects must be annotated with the #[Aspect] attribute.

• Advice: The logic that you want to apply to your target classes. Advice methods must be annotated with the #[Before], #[Around] or #[After] attributes.

• Join Point: A point in the execution of your target classes where you can apply your advice. Join points are defined by the #[Before], #[Around] or #[After] attributes.

• Pointcut: A set of join points where you can apply your advice. Pointcuts are defined by the #[Pointcut] attribute.

• Weaving: The process of applying your advice to your target classes.

• Implicit Aspects: The aspects are applied without any modification to the target classes. The aspect itself specifies the classes or methods it applies to.

• Class-Level Explicit Aspects: The aspects are applied by modifying the target classes, typically by adding the aspect as an attribute to the target class.

• Method-Level Explicit Aspects: The aspects are applied by modifying the target classes, typically by adding the aspect as an attribute to the target method.

Implicit Aspects

Class-Level Explicit Aspects

Method-Level Explicit Aspects

Features

• Advice types: "Before", "Around" and "After"

• Intercept "private" and "protected" methods (Will show errors in IDEs)

• Access "private" and "protected" properties and methods of the subject (Will show errors in IDEs)

• Intercept "final" methods and classes

• Use Transformers from the "Okapi/Code-Transformer" package in your Kernel to modify and transform the source code of a loaded PHP class (See "Okapi/Code-Transformer" package for more information)

Limitations

• Internal "private" and "protected" methods cannot be intercepted

How it works

• This package extends the "Okapi/Code-Transformer" package with Dependency Injection and AOP features

• The AopKernel registers multiple services

  • The TransformerManager service stores the list of aspects and their configuration

  • The CacheStateManager service manages the cache state

  • The StreamFilter service registers a PHP Stream Filter which allows to modify the source code before it is loaded by PHP

  • The AutoloadInterceptor service overloads the Composer autoloader, which handles the loading of classes

General workflow when a class is loaded

• The AutoloadInterceptor service intercepts the loading of a class

• The AspectMatcher matches the class and method names with the list of aspects and their configuration

• If the class and method names match an aspect, query the cache state to see if the source code is already cached

  • Check if the cache is valid:
  • Modification time of the caching process is less than the modification time of the source file or the aspect file

  • Check if the cache file, the source file and the aspect file exist

  • If the cache is valid, load the proxied class from the cache
  • If not, return a stream filter path to the AutoloadInterceptor service
• The StreamFilter modifies the source code by applying the aspects
  • Convert the original source code to a proxied class (MyClass -> MyClass__AopProxied)
  • The proxied class should have the same amount of lines as the original class (because the debugger will point to the original class)
  • The proxied class extends a woven class which contains the logic of applying the aspects
  • The woven class will be included at the bottom of the proxied class
  • The woven class will also be cached

Testing

• Run composer run-script test
  or
• Run composer run-script test-coverage

Contributing

• To contribute to this project, fire up an aspect in any application that works or has 100% working tests, and match every class and method with '*' with any advice type.
• If the application throws an error, then it's a bug.
• Example:

Show your support

Give a ⭐ if this project helped you!

🙏 Thanks

• Big thanks to lisachenko for their pioneering work on the Go! Aspect-Oriented Framework for PHP. This project drew inspiration from their innovative approach and served as a foundation for this project.

📝 License

Copyright © 2023 Valentin Wotschel.
This project is MIT licensed.