Mirror, mirror on the wall (Nomad PHP US 2015)
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The document discusses the concept of reflection in PHP, emphasizing its structure, metadata, and type introspection using the Better Reflection library. It includes examples of using Abstract Syntax Trees (AST) for parsing and manipulation of PHP code, showcasing how to modify class methods dynamically. The presentation highlights current achievements and future plans for improving PHP reflection capabilities.
![// 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(),
]));
}](https://image.slidesharecdn.com/mirrormirroronthewallnomadphpus2015-151218012344/85/Mirror-mirror-on-the-wall-Nomad-PHP-US-2015-30-320.jpg)
![// 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);](https://image.slidesharecdn.com/mirrormirroronthewallnomadphpus2015-151218012344/85/Mirror-mirror-on-the-wall-Nomad-PHP-US-2015-36-320.jpg)
Mirror, mirror on the wall (Nomad PHP US 2015)
- 1. Mirror, Mirror on the Wall James Titcumb NomadPHP December 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?
- 13. What?
- 14. Why?
- 15. How?
- 16. Magic of the AST
- 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') ));
- 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"
- 25. Benefits?
- 28. $reflection = new ReflectionClass( '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)_/¯
- 46. Any questions? :) https://joind.in/16523 James Titcumb @asgrim