James Titcumb's presentation at the PHP unconference 2015 discusses the concept of reflection in PHP and its practical applications using Better Reflection. He explains how to leverage the Abstract Syntax Tree (AST) to modify and inspect PHP classes and methods dynamically. The presentation highlights ongoing work to enhance compatibility and functionality within core reflection in PHP.

1. Mirror, Mirror on the Wall
James Titcumb
PHPem Unconference 2015

2. James Titcumb
www.jamestitcumb.com
www.roave.com
www.phphants.co.uk
www.phpsouthcoast.co.uk
@asgrim
Who is this guy?

3. Reflection

5. © 1937 Disney’s Snow White - disneyscreencaps.com

7. ● Structure
● Metadata
● Values
● Type introspection
● Modification
Reflection

8. How does it work?

9. GET_REFLECTION_OBJECT_PTR(ce);
lc_name = zend_str_tolower_dup(name, name_len);
if ((ce == zend_ce_closure && (name_len == sizeof(ZEND_INVOKE_FUNC_NAME)-1)
&& memcmp(lc_name, ZEND_INVOKE_FUNC_NAME, sizeof(ZEND_INVOKE_FUNC_NAME)-1) == 0)
|| zend_hash_str_exists(&ce->function_table, lc_name, name_len)) {
efree(lc_name);
RETURN_TRUE;
} else {
efree(lc_name);
RETURN_FALSE;
}

10. Okay. What now?

11. github.com/ /BetterReflection
Better Reflection!

13. What?

14. Why?

15. How?

16. Magic of the AST

17. source: http://goo.gl/HORwLQ

18. WTF is AST?

19. use PhpParserParserFactory;
$parser = (new ParserFactory)
->create(ParserFactory::PREFER_PHP7);
print_r($parser->parse(
file_get_contents('ast-demo-src.php')
));

20. <?php
echo "Hello world";

21. AST
`-- Echo statement
`-- String, value "Hello world"

22. <?php
echo "Hello " . "world";

23. AST
`-- Echo statement
`-- Concat
|-- Left
| `-- String, value "Hello "
`-- Right
`-- String, value "world"

24. AST to Reflection

25. Benefits?

26. ReflectionProperty->getDocBlockTypes()
Types!

27. Using Better Reflection

28. $reflection = new ReflectionClass(
'BetterReflectionTestFixtureExampleClass'
);
$this->assertSame(
'ExampleClass',
$reflection->getShortName()
);

29. $reflection = ReflectionClass::createFromName(
'BetterReflectionTestFixtureExampleClass'
);
$this->assertSame(
'ExampleClass',
$reflection->getShortName()
);

30. // In ReflectionClass :
public static function createFromName($className)
{
return ClassReflector::buildDefaultReflector()->reflect($className);
}
// In ClassReflector :
public static function buildDefaultReflector()
{
return new self(new AggregateSourceLocator([
new PhpInternalSourceLocator(),
new EvaledCodeSourceLocator(),
new AutoloadSourceLocator(),
]));
}

31. (don’t try this at home kids!)
Some voodoo...

33. class MyClass
{
public function foo()
{
return 5;
}
}

34. // Create the reflection first
// ***BEFORE*** class is loaded
$classInfo = ReflectionClass::createFromName('MyClass');

35. // Override the body...!
$methodInfo = $classInfo->getMethod('foo');
$methodInfo->setBody(function () {
return 4;
});

36. // Save the class and require it
$classCode = (new CodePrinter())->prettyPrint([$classInfo->getAst()]);
$tmpFile = tempnam(sys_get_temp_dir(), 'br-monkey-patching');
file_put_contents($tmpFile, '<?php ' . $classCode);
require_once($tmpFile);
unlink($tmpFile);

37. // Now create an instance, and call the function...
$c = new MyClass();
var_dump($c->foo()); // will be 4!!!

39. What’s in it for me?

40. The future...

41. ● DONE Currently: rewriting the internals
○ SourceLocators “might” return some code ?!
● DONE Returning AST/Code for method/fn
Ideas/plans - DONE

42. ● WIP More compatibility core reflection
● WIP Reflect core fns with default params
○ This is not currently possible with core reflection
● WIP Modification & exporting
● WIP Reflecting on closures
Ideas/plans - WIP

43. ● Adding a getColumn() function
● PHP 7 compatibility
● @inheritDoc traversal (to inherit type hints)
● Make it faster
Ideas/plans

44. ¯_(ツ)_/¯

45. github.com/ /BetterReflection
Better Reflection

46. Any questions? :)
https://joind.in/15485
James Titcumb @asgrim